2022 Spring Student Research Symposium

Department of Curriculum, Instruction, and Learning Sciences, College of Education and Human Development, Texas A&M University - Corpus Christi

Online learning affects students, instructors, and higher education administration differently. The 24/7 access to course materials, the flexibility of attendance and schedules, increased access to up-to-date information and resources, an abundance of multimedia, availability of open educational resources, and the development of mobile technology are named as significant benefits of online education for both faculty and students (Allen & Seaman 2017; Anderson, 2004; Chute et al., 1999; Colak, 2018). With all the benefits, fewer than 50% of instructors embrace digital strategies. The valid reasons for such avoidance include the need for different set of competencies and proficiencies required for successful online teaching as well as lack of adequate preparation, lack of administrative structures and policies, pressure from the administration, perceived lack of course interactions, perceived lack of quality, the increased amount of preparation time, inability to sustain academic rigor of online courses, legal issues such as accessibility and copyright, lack of instructor compensation, among others. The ability to transition to online teaching came to the forefront in Spring 2020 during the COVID-19 pandemic. Faculty had to adopt digital pedagogies with minimum time and opportunities to prepare (Lee et al., 2021; Tugend, 2020). The numerous challenges and successes of COVID-19-mandated transition to online learning will be analyzed in this phenomenological study aiming to explore one university faculty's transformative digital teaching experiences while transitioning to online teaching during the COVID-19 pandemic and identify essential motivational factors, knowledge, and competencies that impacted faculty's transition. Information can be collected through interviews exploring the views, experiences, beliefs, and motivations of individuals on a specific subject to provide a deeper understanding of phenomena (Gill et al., 2008; Silverman, D, 2013). Data will be analyzed through several re-iterating coding cycles to identify the primary themes of the research. Preliminary findings will be reported.

Keywords: ONLINE TEACHING, DIGITAL PEDAGOGY, DIGCOMPEDU.

¹ Department of Science and Engineering, College of Electrical Engineering, Texas A&M University - Corpus Christi

The use of location and instruction markers for path planning in any set of unmanned aerial system's tasks is crucial to the effectiveness of the individual unmanned aerial vehicles (UAVs). This research implements OpenCV algorithms that allow a UAV to use ArUco markers to receive data related to location and instruction for the purposes of operation. OpenCV algorithms are utilized to develop vision-based solutions to enhance the capabilities of the UAV. The goal for the UAV's operation includes image capture and image processing of objects using ArUco markers for instruction. The use of ArUco markers also increases the effectiveness of object detection for image capture by guiding the UAV. Some image processing techniques included in the experimentation are line contouring, erosion, and dilation where object detection and isolation are possible. This project utilizes OpenCV and Python libraries for the UAV's instructional operation where image processing techniques are implemented on images that are transmitted over the network infrastructure as an application of Internet of Things (IoT).

Keywords: MORPHOLOGY, STRUCTURAL DAMAGE INSPECTION, TELLO SDK, MICROSOFT AZURE, IOT HUB

Department of Engineering, College of Science and Engineering, Texas A&M University – Corpus Christi

Anterior Cruciate Ligament (ACL) injuries are undoubtably some of the hardest injuries to recover from on the lower extremity. Patients report up to 75% degradation in knee quality of life within 20 years post-surgery, however, conventional rehabilitation methods are limited to non-immersive equipment and mostly unquantifiable data to track someone’s recovery progress. Those factors along with the extended recovery time of an ACL injury (8-12 Months) decrease the patient’s adherence to rehabilitation plans. The present study is intended to validate the use of a fully instrumented Bertec Corporation Treadmill along with an immersive virtual reality (VR) motion capture system, to enhance and objectify targeted feedback and biofeedback from motor control as well as sensorimotor performance data. The rehabilitation system components include three PCs which connect a large 270-degree screen, a projector, nine motion capture cameras, and a treadmill with arm supports and force plates. With such a system in place, the process of rehabilitating an ACL injury can be optimized and quantified using motion capture markers to measure range of motion (ROM) in a customizable environment that simultaneously activates sensorimotor functions in a patient by providing a fully immersive experience.

Keywords: ACL RECOVERY, BERTEC TREADMILL

¹ Department of Life Sciences, College of Science and Engineering, Texas A&M University - Corpus Christi

The use of autonomous unmanned aerial vehicles (UAVs) for applications such as exploration and surveillance have grown in popularity with the increase in UAV availability. With applications of exploration and surveillance in mind, and the knowledge of path finding and data exchange in a multi-UAV system, the focus of this research will be to use fiducial marks for path planning and data exchange. Binary square fiducial markers such as ArUco or AprilTag, alongside OpenCV algorithms, will be used to allow the UAV’s camera to detect fiducial markers and plot a course of navigation according to the data related to the identified marker. Structural damage inspection (Fig1) will be another application of this research where OpenCV and image processing techniques will be implemented to collect real-time valuable data. The data collected by the multi-UAV system will be collected and transmitted in real-time to the user as an application of Internet of Things (IoT).

Keywords: UAV, IOT, OPENCV, PATH-PLANNING, FIDUCIAL MARKERS

¹Department of Engineering, Texas A&M University-Corpus Christi ²Collaborator, Coastal and Marine Systems Science, Texas A&M University-Corpus Christi ³Faculty mentor, Department of Engineering, Texas A&M University-Corpus Christi

Limpets are bioindicators of their environment as their growth patterns and physical attributes are related to the conditions in their surroundings. Limpet shell attributes, such as shell volume, length, height, width and thickness, provide an indication of the limpet’s environmental conditions, as the animal spends its resources accordingly to either grow and/or to strengthen its shell, or how the shell is weathered. This research focuses on determining the physical attributes of limpet shells obtained from Hawaii to provide an accurate tool for scientists to compare different shell characteristics within and across multiple shell locations. Multiple physical measures are captured through 3D scanning data and computations through the MATLAB programming tool. These measurements include inner shell volume, outer shell volume, solid shell volume, major axis, minor axis, height, peak shift, and surface area. The 3D measurements are compared to physical measurements, when feasible. For example, solid shell volume is measured using water displacement method. Major and minor axes as well as height are also measured with a ruler for comparison. The characteristics of the shells collected from two different locations, one from Makalawena and the other from Puanwi are presented. The listed physical attributes of the limpet shells are analyzed to establish correlations between the region where the animal grows and the shell characteristics themselves. The focus of this presentation is the development of the engineering tool that is capable of 3D measurements with high accuracy to achieve the scientific goals of the project.

Keywords: ENGINEERING TOOL, IMAGE PROCESSING, IRREGULARLY-SHAPED OBJECTS

¹ Department of Engineering, College of Science and Engineering, Texas A&M University - Corpus Christi

Through the years, Unmanned Autonomous Systems (UAS) such as ground robots and aerial robots, a.k.a. drones, have gained increasing popularity within the Science and Engineering field. They can be used for exploration and data acquisition over areas that are difficult to access and/or for wide variety of missions. UAS have proven to be useful in terms of human-risk reduction and time consumption. Previous studies have shown the feasibility for one operator to control one robot, as well as one operator to control multiple robots via a joystick or a predefine waypoint navigation. However, when it comes to controlling a multi-robot system, in real-time, by a single operator, several challenges arise, e.g., it is difficult to control the direction of a team of robots or a swarm, the right timing for the execution of tasks, or simply selecting certain robots within the team. In this research project, we propose the development of an intuitive way to control multi-robot system via Human Body Language. We have defined a Human-Machine interaction where body posture and gestures will be used to control the drone in a more intuitive manner, this is called semi-autonomous mode. Programs such as MATLAB and VICON Nexus are used to obtain and analyze data, and to control the Tello drone. The focus of this research is to broaden the capabilities of UAS and their integration within our everyday lives. This type of project can easily be applied to other fields such as the medical field (e.g., search and rescue operators), the military (e.g., exploration of unknown territory), and even private companies.

Keywords: PROGRAMMING, UNMANNED AUTONOMOUS SYSTEMS, ROBOTICS

Digital Data Processing Laboratory, Department of Engineering, College of Science and Engineering, Texas A&M University - Corpus Christi

Internet of Things, or IoT, has emerged as a method for cloud-enabled data collection and sharing by connecting everyday objects to the internet. Further, by allowing the interconnection of transmitted data, IoT devices create a network of communication among objects, sensed data, and users. This work uses an IoT development board equipped with a microcontroller to perform sensor data collection, fusion, and processing to assess simulated data that represents a muscle, perform signal processing on the data, and based on results determine the optimal frequency with which vibrations can be adjusted for improving the state of the source of stimulus. The initial work focuses on simulated signals from IMU and pressure sensors. In this work, the preliminary results from setting up the IoT systems, sensor data acquisition and transmission, signal processing, and vibration frequency identification will be presented.

Keywords: INTERNET OF THINGS, SIGNAL PROCESSING, SENSORS, SENSOR FUSION

1 Department of Life Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi

When creating an algorithm to control a swarm of drones to complete the same or different tasks in unison, it is important to have maximum control and minimal safety risks during operation. The purpose of this research will be to test and evaluate how several different types of drones fly in order to calibrate the range that they may be able to react to one another and avoid collision. The term to determine the range at which a drone will sense an obstacle and react will be referred to as a ‘safety bubble’. The test and evaluation of flight parameters of each drone will be done using the Vicon Motion Capture Systems in the Collaborative Robots and Agents Lab (CORAL) to record values as several types of drones complete the task of taking off, flying to a destination, and landing. These values will be graphed and compared in MATLAB in order to determine the safety bubble size of each drone. If a drone is a newer model is will likely react with less time than an older model, therefore, it will likely have a smaller safety bubble. Sensor fusion will be used to determine the size of a safety bubble by having multiple layers of sensor arrays that will detect an object so the drone will have time to change course. When the drone senses an object it will react similarly to how a gas particle does during collision. The sensors will detect the obstacle and the drone will react by flying in the opposite direction, preventing collision.

Keywords: DRONE, TEST, SWARM

1 Department of Engineering, College of Science and Engineering, Texas A&M University – Corpus Christi

Recent studies have found that many basic mental abilities, like motivation, attention, problem-solving skills, and sensorimotor skills such as body coordination, seem to deteriorate in space, particularly during long-duration space missions. The main objective of this work is to develop a methodology that will assist in evaluating astronauts' performance and identify parameters or key indicators that can be used to monitor decrements in users' performance. The goal is that through the implementation of this methodology, we should be able to detect at early-stage potential sensorimotor problems or mental problems. For this work, we are combining a body-tracking system named VICON with sensor technologies named K-Invent Forces. Vicon Nexus is a modeling and processing system used for movement analysis, while K-Invent wireless devices can assess subject forces in real-time. The user's performance will be supervised by executing a set of interactive activities. If key indicators can be identified during subject interaction, a set of aspects can be identified and used to improve crew members' immersion, motivation, attention, and body coordination. Using MATLAB, a numeric computing environment, we will analyze data or variables imported from Vicon Nexus (e.g., joint angles and positions, accelerations, etc.) and K-Invent (e.g., forces, position, etc.) in real-time and offline. We expect to create a methodology that will assist in identifying and detecting key indicators to decrements in user's performance, which can also be used as a platform to mitigate the problem by generating detection, prevention, and treatment programs that target sensorimotor skills and mental abilities.

Keywords: SENSORIMOTOR SKILLS, SPACE APPLICATION, AUTOMATION, HEALTH INFORMATICS

¹ Department of Engineering, College of Science and Engineering, Texas A&M University - Corpus Christi; ² NASA JSC

During long-duration space missions, astronauts have to face different challenges such as adapting to micro-gravity environments, performing scientific experiments, completing maintaining tasks, performing extravehicular activities, etc. Whether crewmembers are inside or outside the spacecraft, they require to have a suitable lighting system to assist in the missions. Unexpected challenges can arise for astronauts traveling to interplanetary locations, causing the need to adjust and adapt the spacecraft’s lighting system for interior and exterior exploration activities. Current lightning systems are directly installed into the infrastructure of the vessel, which makes them hard to fix, sometimes impossible due to its complexity of repairing, and not portable at all. To address this problem, we present the design of a Modular Reconfigurable Lighting System (MRLS) for spacecraft habitats beyond low earth orbit, that attempts to bring a solution to this challenge. The MRLS is composed of three main modules, i.e., the LED (L) module consisting of the LED circuit and a thermal cooling system to elongate the lifespan of the LEDs; the battery (B) module consisting of a regulator, rechargeable 12V battery and control panel; and the lens and diffuser (LD) module consisting of 3D printed interchangeable lenses and diffusers for different optics and beam control options. The MRLS provides both, a portable solution by means of the rechargeable 12V battery and a fixed solution through a connector mechanism. The regulator controls the voltage output of the battery which in turn, controls LED illumination levels from 100-1000 lux. The L module can be operated via switches to change the color temperature lighting in the L module (options: 4000 K, 6000 K or their combination). All components are designed in Autodesk Inventor to develop proper housing for each of the three modules. Velcro and handles can be attached and detached from the housing for flexibility, portability and hard mount to vehicle structures.

Keywords: LED, CIRCADIAN RHYTHM, ISS, TSGC

¹ Department of Life Sciences, College of Science and Engineering, Texas A&M University - Corpus Christi; ² The Rockefeller University, New York, New York; ³ Hunter College, City University of New York, New York, New York

Bottlenose Dolphins (Tursiops truncatus) are commonly found in the waters of Turneffe Atoll, Belize, where they inhabit areas that vary in physical features. Variables such as water depth, prey abundance, and location are related to the spatial dispersion of bottlenose dolphins. The spatial dispersion (areas within a pod) and orientation (line abreast, parallel, scattered, facing inward) of bottlenose dolphin pods have yet to be examined in relation to pod size, substrate type, and behavioral state. We explore how abiotic and biotic factors may affect bottlenose dolphin movement. Video recordings of free-swimming bottlenose dolphins were taken by drone in Turneffe Atoll, Belize and transformed into a series of screenshots for data extraction. Pod size (3-15), substrate type (boundary, seagrass, mixed), and behavioral state (forage, social, rest, travel) were categorized from the screenshots. Spatial dispersion and orientation were measured in ImageJ and data were averaged per video. Spatial dispersion of dolphin pods was significantly related to pod size, substrate type, and behavioral state (F = 3.375, P < 0.05). Pods were most dispersed when engaged in social activities, suggesting frequent events of separation. When swimming over a mixed substrate, spatial dispersion was also high, potentially indicating a lack of predators or an abundance of non-schooling prey. Small pods (n < 15) showed low spatial dispersion, suggesting a potential defensive strategy against predators. Assessment of dolphin activity researched using non-invasive techniques yield insights to how dolphins use their habitat when exposed to minimal human encroachment.

Keywords: DRONE, TURNEFFE ATOLL, IMAGEJ

Department of Life Sciences, College of Science and Engineering, Texas A&M University - Corpus Christi

Packery Channel is a eutrophic environment in a small jetty system that allows plankton migration between Corpus Christi Bay and the Gulf of Mexico. Plankton are marine organisms that play a critical role as primary food sources for many animals, such as corals. Recently, corals have been found surviving in the dynamic conditions of Packery Channel. However, there has been limited research conducted on plankton abundance and diversity due the channel recently reopening. Therefore, this project aims to identify and quantify the abundance of plankton present in Packery Channel by collecting samples at various tides during the full moon cycle over a year-long period. Plankton nets were towed (phytoplankton = 63 μm and zooplankton = 243 μm) along a 50-meter transect alternating between the North and South sides of Packery Channel to encompass the whole channel. It is hypothesized that the highest abundance will occur during summer and night periods and the lowest abundance will occur during winter and daytime periods. This is due to the difference in light availability, tide flow, and temperature which has been found to make an impact on plankton. Results from this study indicate the corals within Packery Channel potentially have resources available when under stressful conditions such as limited sunlight. Understanding the seasonal dynamics of plankton within Packery Channel is necessary to expand research within estuarine systems and aid in understanding how corals survive in extreme conditions.

Keywords: HETEROTROPHY, PLANKTON ECOLOGY, CORALS, ADAPTATION

¹ Department of Life Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi

The budgeting of defensive and appetitive behaviors triggered in response to aversive stimuli modulates an imperative learning process pertinent to both humans and animals alike (Shields-Johnson et al. 2013). Aplysia possesses similar, yet simplified neural networks to humans, presenting a unique opportunity to expand the knowledge about long-term memory (LTM) formation (Kandel, 2001) and even manipulate the methods of administration at a behavioral level to possibly maximize LTM (Zhang et al. 2012). A standard aversive training protocol, consisting of trials of electric stimuli delivered at a constant 30-min inter-trial interval (ITI), is known to induce two behavioral modifications at 24, but not at 72 hours: long-term sensitization (LTS), which manifests as enhancement of defensive reflexes, and long-term feeding suppression (LTFS, Shields-Johnson et al. 2013). An enhanced learning protocol (ELP), derived from a computational algorithm based on a biochemical model with variable ITIs (10, 10, 5, 30 min), is known to induce an augmented LTS lasting for several days (Zhang et al. 2012). Because the effects of ELP on LTFS remains unknown, this project aimed to determine if this method of training enhances LTM by prolonging not only LTS, but also LTFS. Defensive reflexes and feeding were measured before and 24, 38, 48, 62, and 72 hours after ELP delivery, while untrained animals were used as controls. Data was analyzed with two-way repeated measures ANOVA followed by Fisher LSD tests. Although preliminary, the results of this study indicate the presence of LTFS at all time points, and even showed a trend of an increase in LTFS as time progressed. Data on defensive reflexes demonstrate a trend attributable to LTS formation, corroborating the findings of Zhang et al. (2012). Current data suggest that the ELP prolongs LTM duration and therefore exhibits encouraging evidence of a paramount learning method that may enhance LTM.

Keywords: PLASTICITY, COGNITION, NEUROSCIENCE

¹ Department of Life Sciences, College of Science and Engineering, Texas A&M University– Corpus Christi

Industrial activity can alter environmental conditions in a variety of ways that affect seagrass communities and associated fauna. Seagrass beds near Ingleside On The Bay, TX are potentially impacted through increased sedimentation and reduced light penetration. A habitat quality assessment aimed to compare seagrass and animal indicators along an expected gradient of shipping disturbances which affect sedimentation. Seagrass metrics including species composition, shoot morphology, and biomass described the seagrass meadow condition at each sample site. Epiphytic biota and biomass data provide additional seagrass condition context. Higher trophic level organisms, and predation intensity (presence or absence of higher trophic level organisms) are observed using squid pops, comprised of squid pieces (~1cm^2 in size) tied along trot lines deployed in a cardinal direction pattern at each sample site. Preliminary observations found seasonal variation in predation activity, observed as a sudden decline in feeding activity with decreasing water temperature. Sites in disturbed areas displayed higher feeding activity, particularly in areas with mixed composition of seagrass species relative to monotypic seagrass species sites in undisturbed areas. Feeding activity is expected to increase with seasonally warmer water temperatures. More intensive feeding is expected in areas with dense seagrass beds away from potential disturbance gradient. Identification of epiphytic biota through DNA barcode sequencing will provide more detailed understanding of the faunal diversity in disturbed and undisturbed areas.

Keywords: SEAGRASS, SEAGRASS INDICATOR, EPIBIOTA, ANIMAL INDICATOR, SQUID POP

¹ Department of Life Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi; ² Texas A&M AgriLife Research Mariculture Laboratory – Corpus Christi

In Texas, the Eastern Oyster, Crassostrea virginica, is an ecologically and economically valuable benthic organism and has been shown to adapt to a variety of environmental changes. However, measuring oyster physiology has proven difficult due to the oyster’s response of closing their shell for long periods of time as a defense mechanism. Therefore, this project aims to test various methods of measuring oxygen consumption rates to determine oyster tolerance thresholds under changing environmental conditions to inform place-based management of oyster farming and restoration. This project will test two methods, the procedure of notching the oyster with a Dremel and a blocking procedure that uses a plastic wedge to prevent the oyster valves from closing shut completely. However, with both these procedures, there is the potential of the oysters becoming stressed which could alter their physiological response during experimentation. Therefore, these techniques will be compared to help researchers understand the impact of additional stress when conducting physiological measurements, with the goal of successfully opening the valves of the oysters to measure oxygen consumption rates over set periods of time. The results of this work will assist in retrieving data on dissolved oxygen consumption rates and oyster shell calcification when exposed to multiple, interacting stressors (i.e., salinity and temperature). Understanding the oyster’s organismal response and tolerance threshold to changing environmental conditions will provide data that supports policy and management of Texas oyster ecosystems.  

Keywords: NA

Department of Life Sciences, College of Science and Engineering, Texas A&M University - Corpus Christi

Studies of copulatory fit, the interaction of the genitalia during intromission, provide insights on the biomechanics of mating. Past studies on copulatory fit have primarily used insects as model species, although a recent approach has been developed to understand how genitalia interact during copulation in larger taxa. In this study, the copulatory fit of sexually mature post-mortem southern sea otters (Enhydra lutris nerei) was examined. Frozen-thawed excised penises were inflated with melted Vaseline to simulate erection. Silicone endocasts were made of the vaginal lumen of frozen-thawed female reproductive tracts. Each penis (n = 3) and vaginal endocast (n = 3) was 3D scanned to create digital models. Each digitized penis was positioned on each digitized vaginal endocast in simulated copulation and rotated 90, 180, and 270 degrees to determine the angle of best fit. The most surface contact and optimal fit occurred in a dorsal-ventral position. If sea otters mate in a non-dorsal-ventral position, it is hypothesized that pre-copulatory sexual conflict will ensue.

Keywords: MARINE MAMMAL, CALIFORNIA

¹ Department of Life Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi; ² Smithsonian Environmental Research Center

In Winter 2021, Uri brought historically low temperatures to Texas. Avicennia germinans mangrove populations in the salt marsh/mangrove ecotone were heavily impacted; damage varied from loss of exterior canopy leaves in Boca Chica, to death of above ground tissue in many shrubs as far south as Laguna Atascosa. There has been some above ground biomass recovery, but mangrove population density is drastically reduced and at many sites, there has been no recovery of adults. Recolonization of Avicennia will require establishment by the propagule life stage. Both biotic and abiotic factors and their interactions will play an important role in recovery. In general, Uca (fiddler crabs) are considered to have a facilitative relationship with Avicennia, burrowing oxygenates sediment in the rootzone of trees/shrubs. Herbaceous salt marsh species facilitate establishment and growth of mangroves in Florida and Belize. However recent findings indicate that in the unique Texas arid salt marsh habitat, Uca bury many of the Avicennia propagules that strand within the protective salt marsh habitat. Avicennia propagules consist of photosynthetic cotyledons that remain above the sediment and an embryonic root that anchors in the sediment. Burial often results in mortality of propagules and newly established seedlings. In contrast, nitrogen increases growth in height and leaf production in Avicennia seedlings in salt marsh ecotones. Understanding how Uca and soil nutrients impact propagule establishment will help us to predict the rate of recovery of Avicennia in Texas. We will study the direct effects and interactions of Uca and nitrogen on Avicennia propagules that strand in the salt marsh ecotone in a fully crossed experiment. We hypothesize that 1) a greater percentage of propagules will survive and establish when Uca when is excluded 2) nitrogen will allow for greater survival and establishment of propagules and 3) nitrogen will ameliorate the negative effect of Uca.

Keywords: DISTURBANCE ECOLOGY, SPECIES INTERACTION, EUTROPHICATION

¹ Department of Life Sciences, College of Science and Engineering, Texas A&M University - Corpus Christi; ² Department of Biological Sciences, Old Dominion University

The genomes of organisms stored in museums hold a wealth of information that is challenging to sequence. Recent success in sequencing desiccated museum insects involved using whole genome amplification (WGA) and enzymatic repair (NEBNext FFPE Repair Mix) of DNA damage, but these techniques have not been tested on fishes. The Smithsonian Museum currently hosts one of the largest single collections of fishes which was conducted over a century ago on board the RV Albatross and consists of over 27,000 jars, or `lots`, of marine fishes from the Philippines alone, and all were preserved in rum distillates and stored in 70% EtOH which should enable DNA sequencing. Here, we use factorial treatment combinations to test for the effects of WGA, enzymatic repair, and amount of DNA input on whole genome shotgun sequencing of RV Albatross and contemporary samples (preserved in 95% EtOH) of three species of Philippine marine fishes. A total of 74 libraries (30 WGA, 44 NoWGA) were sequenced (2 x 150bp) using one individual per era and species when possible. After adapter trimming, quality filtering, and removal of contaminant sequence reads, contemporary libraries were assembled de novo, and all libraries were mapped to the longest 100 contigs from the best genome assembly of each species according to n50 and BUSCO analysis. Contrary to expectation, WGA had a negative effect on depth of coverage and number of informative positions for historical libraries (p < 0.05). For both contemporary and historical libraries, neither enzymatic repair nor DNA concentration had a consistent effect on number of SNPs or depth of coverage (p > 0.05). Overall, we were able to successfully recover enough DNA to meaningfully test for differences between contemporary and historical libraries and perform downstream population genomic analyses, using a standard shotgun library preparation protocol and $75 of sequencing per library.

Keywords: MUSEOMICS, NEXT GENERATION SEQUENCING, SHORT READ ASSEMBLY, BIOINFORMATIC PROCESSING, REEF HABITAT CONSERVATION

¹Department of Life Sciences, College of Science and Engineering, Texas A&M University-Corpus Christi; ²Center for Coastal Studies, Texas A & M University-Corpus Christi

Pomacea maculata is the largest freshwater snail in the world. This native of Brazil was introduced to the southeastern United States in 1989. A documented voracious consumer, it continues to spread and threaten wetlands in this region, where it happens to overlap with two highly invasive aquatic macrophytes that also hail from Brazil: Salvinia minima and Eichhornia crassipes. This invasive community poses a great threat to native wetland ecosystem structure and function, but also presents a unique opportunity to examine multi-species interactions with shared evolutionary histories. The primary objectives of this study are threefold: 1) to determine whether P. maculata diet reflects a preference for native Louisiana macrophytes over the co-evolved invasive plants; 2) to determine whether P. maculata can be a viable biocontrol agent for S. minima and E. crassipes in their invaded range; and 3) to compare P. maculata herbivory in its invaded and native range. Project objectives will be addressed through a series of controlled feeding trials using snails and plants from local populations in Louisiana and Mato Grosso (Brazil).

Keywords: AQUATIC, EXOTICS, GASTROPOD, NONINDIGENOUS, PANTANAL, SWAMP

1 Department of Life Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi

Coral reefs are one of the most biodiverse and valuable ecosystems on the planet, and healthy reef systems can sustain a multitude of marine species, defend coastlines from storm surges, and provide employment for people in local communities. The health and prosperity of reef-building corals is largely attributed to the partnership with their algal symbiont, zooxanthellae. A large body of research contributes to understanding how corals and zooxanthellae respond to individual stressors. However, fewer articles clarify how multiple interacting stressors may threaten these ecosystems and disturb corals’ relationship with zooxanthellae. Therefore, this research aims to quantify changes in zooxanthellae density in corals that have been subjected to the interactive effects of thermal stress and nutrient loading. Corals were collected from two sites in Kāneʻohe Bay, Hawaiʻi, encompassing a gradient of temperature and nutrient influence. For one month, corals were subjected to four experimental treatments (Control, Heated, Nutrient, Heated + Nutrient). Fragments were collected at the beginning and end of the experiment, flash frozen in liquid nitrogen, and shipped back to TAMU-CC for subsequent analysis. Coral experimentation began with airbrushing the coral tissue to remove it from the skeleton, yielding tissue slurry used for the biological assay. The organic matter was lysed using a tissue homogenizer and then centrifuged to create coral pellets. The biological pellets were then resuspended in the phosphate-buffered saline (PBS) and vortexed to create an aliquoted subsample which could then be counted under a microscope using a hemocytometer. Upon analyzing the experimental results, it is hypothesized that the corals that underwent the Heated + Nutrient treatment may be more susceptible to bleaching due to the combined stressors. This study will aid our understanding of how corals in Kāneʻohe Bay respond physically to interacting stressors.

Keywords: RESILIENCE, ANTHROPOGENIC, PHENOTYPE

Department of Life Sciences, College of Science and Engineering, Texas A&M University - Corpus Christi

In Aplysia, in vivo exposure to aversive stimuli (i.e., electrical shocks) causes feeding suppression and a reduction in excitability of B51, a neuron linked to biting decision-making (Shields-Johnson et al. 2013). A short-term (15 min) decrease of B51 excitability can be induced in a preparation of the isolated Aplysia nervous system in which electrical stimulation of afferent nerves is used as in vitro training (Weisz et al. 2017). Previous studies have revealed that the gaseous neurotransmitter nitric oxide (NO) is necessary for short-term B51 decreased excitability (Farruggella et al. 2019). However, when the downstream targets of NO modulation guanylyl cyclase (sGC) and protein kinase G (PKG) are pharmacologically blocked, short-term B51 decreased excitability is only partially prevented, suggesting the contribution of another NO-dependent biochemical cascade. In this ongoing study, we are examining the role of S-nitrosylation in the expression of training-induced short-term B51 decreased excitability by blocking this process with the selective inhibitor TEMPOL. Four groups of preparations are being used: untrained/vehicle (artificial seawater), trained/vehicle, untrained/TEMPOL, and trained/TEMPOL. Each preparation is initially incubated for 30 minutes with either TEMPOL or vehicle. Following incubation, the excitability of B51 is measured before (pre-test) and 15 minutes (post-test) after the training or untraining protocol. For each excitability measurement, the percent change is calculated as

, and the Kruskal-Wallis test, followed by the Dunn’s post-hoc comparisons, are conducted to isolate the sources of significance. Although statistical significance has not been achieved yet, current results show a trend that short-term B51 decreased excitability is partly blocked in the trained group incubated with TEMPOL. If confirmed, this result would demonstrate a contribution of S-nitrosylation in short-term B51 decreased excitability and would indicate that two NO-dependent biochemical cascades sustain this learning-induced plasticity: one mediated by a sGC-PKG pathway, and one regulated by a S-nitrosylation process.

Keywords: NEUROTRANSMITTER, NEUROBIOLOGY, MEMORY

Department of Life Sciences, College of Science and Engineering, Texas A&M University - Corpus Christi

Long-term memory formation is known to generally require gene transcription (Kandel 2001). Previous research within the marine mollusk Aplysia revealed that repeated exposure to aversive stimuli induces a lasting enhancement of defensive responses, known as long-term sensitization (LTS). LTS is mediated, at least in part, by long-term increased excitability (LTIE) of sensory neurons (SN), which is known to depend on gene transcription (Byrne and Hawkins 2015). Repeated exposure to aversive stimuli also induces long-term feeding suppression (LTFS) via a long-term decreased excitability (LTDE) of decision-making neuron B51 (Shields-Johnson et al. 2013). However, it is unknown whether B51 LTDE depends on transcription processes like those in the defensive circuits. Therefore, this study examines the molecular requirements for LTFS by determining whether B51 LTDE is transcription dependent. Actinomycin D (ACT-D) is being used to selectively inhibit gene transcription (Montarolo et al. 1986). This project utilizes a previously established in vitro preparation that includes the neural circuits responsible for LTS and LTFS. Electrical stimulation of afferent nerves from the body wall to mimic aversive training in vitro co-induces SN LTIE and B51 LTDE lasting 24 h (Weisz et al. 2017). Ongoing experiments utilize 4 groups: trained/vehicle, trained/ACT-D, untrained/vehicle, and untrained/ACT-D (Weisz et al. 2017). Statistical analysis is being conducted using the Kruskal-Wallis test (Farruggella et al. 2019). Current results indicate that ACT-D is effective in blocking the expression of SN LTIE, as previously shown (Montarolo et al. 1986). Regarding B51, although overall statistical significance across groups has not been reached yet, current findings show a trend that LTDE expressed in the trained/vehicle group is blocked in the trained/ACT-D group. If these results are confirmed statistically, they will demonstrate that ACT-D inhibits B51 LTDE, thus indicating that B51 LTDE requires transcription processes for long-term memory formation analogous to SN LTIE in the defensive circuits.

Keywords: ELECTROPHYSIOLOGY, LEARNING, PROTEIN SYNTHESIS

1Department of Life Sciences, College of Science and Engineering, Texas A&M University-Corpus Christi, TX, USA; 2University of Hawaiʻi, Hawaiʻi Institute of Marine Biology, Kāneʻohe, HI, USA

In Kāne’ohe Bay Hawai’i, the second most dominant coral species, Montipora capitata is an ecologically important reef building coral that has shown to be resilient to environmental changes. However, ocean acidification may compromise the structural integrity of the coral's skeleton threatening the species’ resiliency. Therefore, this project will analyze various biological response variables of M. capitata under the stress of ocean acidification (OA). OA is a change in ocean water chemistry due to an increase in atmospheric carbon absorption, which decreases the pH and aragonite saturation state. This also increases the amount of hydrogen ions in the water, which will impact the total alkalinity, or the ability of the water to neutralize ions. Previous research has stated that a lower aragonite saturation state negatively impacts the coral’s ability to calcify under OA conditions. Contrarily, the Proton Flux Hypothesis states that the increase in hydrogen ions limits coral calcification under OA. To better understand coral growth under OA conditions, corals were exposed to a control and 3 experimental treatments varying in pH and total alkalinity levels, over a month-long experiment. Following experimentation, individual biological response variables from each coral will be measured. These variables include the concentrations of chlorophyll and symbiodinium, along with the protein content and changes in the skeletal density of the coral host. It is hypothesized that the combination of low pH and total alkalinity will have a synergistic effect on the coral's skeletal density. However, the symbiodinium and chlorophyll will experience an antagonistic effect from the changes in water chemistry. The result of this work aims to determine the driving forces behind the dissolution of coral skeletons under OA conditions in order to support the Proton Flux Hypothesis.

Keywords: SYMBIOSIS, CALCIFICATION, CHLOROPHYLL A, CHLOROPHYLL C2, ZOOXANTHELLAE

Department of Life Sciences, College of Science and Engineering, Texas A&M University-Corpus Christi

Computed tomography (CT) has been an essential tool for imaging anatomy in a clinical setting. CT scans can provide insights on genital interactions between the sexes during intromission and is a valuable tool for species with internal fertilization as copulatory biomechanics can be discerned during penile penetration. We use CT scans of orcas (Orcinus orca) in simulated copulation to increase understanding of genital co-evolution and copulatory fit between the sexes. The penis of a postmortem sexually mature orca was inflated with pressurized saline to simulate erection and inserted in a ventral-ventral positioning into the vagina of a postmortem sexually mature female orca. The specimens were CT scanned in simulated copulation and resulting image slices were segmented by tissue type to create a 3D visualization of the genitalia interacting and determine significant landmarks in contact between the sexes. The ventral-ventral positioning produced a tight fit between the genitalia. One major vaginal fold was located cranially in the vagina. The integument of the penis maintaining contact throughout the vagina until tapering at the cervix, maintaining contact with the right distal wall of the vaginal tissue. Understanding of contact points between the sexes yields insights into possible stimulatory functions of genital contact in cetaceans (whales, dolphins, and porpoises) and sexual selection forces driving reproductive morphological co-evolution.

Keywords: MAMMAL, KILLER WHALE, IMAGING, TECHNOLOGY

¹ Department of Life Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi; ² Department of Ecology and Conservation Biology, College of Agriculture and Life Sciences, Texas A&M University – College Station

Many freshwater fishes endemic to spring-fed tributaries of the lower Rio Grande within Texas exhibit small, highly fragmented distributions and are a priority for conservation. The five target species (Dionda diaboli, D. argentosa, Cyprinella proserpina, Etheostoma grahami, and Notropis megalops) in this study have distributions that lie almost entirely within two native fish conservation areas, deemed important for maintaining the state’s native fish diversity. Previous research reported low levels of haplotype and microsatellite diversity of D. diaboli and D. argentosa as well as a sympatric species of Notropis. Due to the extreme vulnerability of these species, assessing levels of standing genetic diversity at the genome level is essential for conservation. Each target species will be collected across multiple sites in the Pecos and/or Devils Rivers. Double digest restriction-site associated DNA (ddRAD) sequencing will be used to characterize single nucleotide polymorphisms (SNPs) for each species across the genome, and patterns of genetic variation within and among sampling localities will be assessed. Additional museum samples (>30 for each species) will be used to facilitate comparisons of contemporary diversity with that of the recent past. This project will provide information on standing genetic diversity (neutral and putatively adaptive) and connectivity among sampling localities within species, allowing managers to prioritize actions on areas harboring vulnerable populations.

Keywords: GENETIC DIVERSITY, WILDLIFE MANAGEMENT, POPULATION GENETICS, RIO GRANDE, TEXAS

¹Department of Life Sciences, College of Science and Engineering, Tidal Hall Life Science Research Laboratory, Texas A&M University-Corpus Christi; ²Department of Kinesiology, College of Education and Human Development, Exercise Physiology and Biochemistry Laboratory (EPBL), Texas A&M University-Corpus Christi

Type 2 Diabetes (T2D) is among the chronic diseases increasingly affecting the human population. This disease potentially results in the interruption in the production of insulin and/or the dysregulation of insulin signaling which may facilitate skeletal muscle mass loss. Exercise is a known stimulus of muscle mass gain or retention. During exercise, skeletal muscle temperature increases (~39°C), however, it is unknown if this increase in temperature alone may influence the transcriptome related to skeletal muscle growth. PURPOSE: The aim of this study was to identify if thermotherapy (heat stress mimetic) may influence genes related to muscle growth and atrophy. METHODS: Human Skeletal Muscle Myoblasts (HSMM) and Diabetic Type 2 Human Skeletal Myoblast (D-HSMM) were purchased from Lonza Inc. (Lonza Inc, Walkersville, MS). HSMM and D-HSMM were cultured until reaching a confluency of 70-80%. Both D-HSMM and HSMM were exposed to an acute bout of thermotherapy (40°C) in experimental well plates. All well plates were treated at a one-time for 30 min. Control well plates were kept at 37°C. The experimental well plates were treated for 24 hours following an initial 48-hour incubation at 37°C. Post-thermotherapy treatment consisted of cell observation, cell viability, and preparation for gene expression. To perform gene expression, RNA was isolated from D-HSMM and HSMM, converted to cDNA, and a real-time polymerase chain reaction (qRT-PCR) was used to assess Activin-A Receptor Type 2B (ACVR2B) and b-catenin (CTNNB1) to a housekeeping gene (GAPDH). RESULTS: Following gene expression analysis, it was determined that ACVR2B yielded the highest change (~1-fold) in D-HSMM. For HSMM, CTNNB1 yielded the highest change (~1-fold). CONCLUSION: These preliminary results suggest that ACVR2B expression, which is the prime myostatin receptor during thermotherapy could potentially facilitate greater muscle atrophy in T2D skeletal muscle. However, the thermotherapy-induced increase in CTNNB1 expression in the normal, healthy skeletal muscle cells may suggest greater androgen receptor (AR) activation and a role in skeletal muscle growth due to the reported actions of b-catenin on AR activation.

Keywords: TYPE II DIABETIC MUSCLE CELLS, HEAT-STRESS, MUSCLE HYPERTROPHY, THERMOTHERAPY, GENE EXPRESSION

Department of Life Sciences, College of Science and Engineering, Texas A&M University - Corpus Christi

The Corpus Christi Bay sea-surface microlayer (SML, air-water interface) has been impacted periodically by harmful algal blooms (HABs), an accumulation of micro or macro algae toxins. SML, a thin surface layer that exchanges energy and matter between the ocean and atmosphere, is commonly enriched in organic compounds relative to the rest of the water column. Algae are rich in short-chain normal alkanes (n-alkanes). The expansive proliferation of HABs cause depletion in oxygen content of the bay’s water and exerts stress on several terrestrial and marine life forms. In this study, algal n-alkane variations of the microlayer throughout the year will be analyzed. Studying variations in its chemical composition throughout the year may enlighten our knowledge on the occurrence of HABs in the Corpus Christi Bay SML. Efforts will be concentrated on sea-surface microlayer sampling using the glass plate method, the extraction of organic compounds from samples in preparation of microlayer extracts for GC/MS analysis, and the interpretation of GC/MS data. Once composition data is obtained, results will be used to investigate the possibility of using variations in microlayer composition to predict the onset of HABs in Corpus Christi Bay.

Keywords: HARMFUL ALGAL BLOOMS, MICROLAYER, AQUATIC / TERRIGENOUS RATIO (ATR)

1Department of Life Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi

Reef-building coral species are found in relatively stable environments with specific environmental conditions such as water temperatures ranging from 25^◦C-29^◦C. However, two cryptic coral species (non-reef building), Astrangia poculata, and Oculina diffusa were recently documented in a shipping channel in Corpus Christi, TX. However, there is little information regarding these coral colonies in Corpus Christi, TX. Therefore, this study aims to investigate the primary feeding mechanism of the cryptic coral species to understand the survival strategies. To do this polyp sizes and abundance were compared per colony, seasonally over a 100-meter transect. Coral colony samples were collected from Packery Channel, Texas seasonally over a year, and each of the polyps was counted and sized for area. Polyps were significantly smaller during the Fall season compared to the Winter colonies. The change in the average polyp size over the year suggests that these corals adjust their feeding mechanisms in response to their fluctuating environmental conditions. In addition, there was also a significant difference in the mean area of the polyps between the two locations of the colonies on the shipping channel (bay side or gulf side), with the bay side being larger overall. The significantly larger size of the bay side suggests that cryptic coral species adjust their feeding mechanisms based on location within the shipping channel. These findings provide insight into how the cryptic coral species survive in the dynamic conditions present in Corpus Christi, TX.

Keywords: CORAL SURVIVAL, DYNAMIC ENVIRONMENTS, POLYP LENGTHS, OLIGOTROPHIC, HETEROTROPHY

¹ Department of Mathematics and Statistics, College of Science and Engineering, Texas A&M University – Corpus Christi; ² Laboratory of Computational Technologies for Modeling Multiphysical and Multiscale Permafrost Processes, Institute of Mathematics and Information Science, North- Eastern Federal University; ³ Department of Mathematics and Statistics, College of Science and Engineering, Texas A&M University – Corpus Christi

This presentation deals with the spatial-temporal dynamical models of two-species competition in 1D and 2D spaces. We have applied factor analysis to the results of tens of thousands of simulations with different combinations of parameters and initial conditions. Firstly, we have found that initial populations, if they are not too small, don’t affect equilibriums. Secondly, we have discovered that the diffusion rate has an impact on whether one or both species survives. Thirdly, the ratios of birthrates to competition parameters play significant role in which of two species survives.

Keywords: COASTAL SPATIAL-TEMPORAL SYSTEMS, SPATIAL-TEMPORAL DYNAMICAL MODELS, POPULATION DYNAMICS, FACTOR ANALYSIS

Department of Mathematics and Statistics, College of Science and Engineering, Texas A&M University - Corpus Christi

Differential equations (DEs) play a key role in modeling the physical, chemical, and biological processes. Virtually every phenomenon occurring in nature can be described by an equation with dependent variable(s), more than one in some instances, and an independent variable(s). Only in some special circumstances, the DEs are tractable to certain well-known analytical techniques. In other instances, the solutions are approximated by prominent collocation methods such as finite elements, finite differences, finite volume techniques etc. Unfortunately, for certain Boundary Value Problems (BVPs) devising a proper approximation method is both challenging and difficult.  In this work, we study a feed-forward multilayer perceptron Artificial Neural Network (ANN) framework to approximate the solution to varieties of two-point BVPs. The trail solution is the sum of two parts: the first part satisfies the boundary conditions while the second approximates the solution which is obtained by the inputs to the number of hidden layers. The mean-squared loss function is minimized by a class of gradient descent optimization methods to obtain the desired output. Our plan is to employ the proposed deep-learning architecture to a variety of DEs and report the convergence of the ANN output.   

Keywords: MACHINE LEARNING, PYTHON, TENSORFLOW, NUMERICAL OPTIMIZATION, UNSUPERVISED TRAINING.

Department of Mathematics and Statistics, College of Science and Engineering, Texas A&M University – Corpus Christi

In this work we consider temporal-spatial models of one species population distribution in heterogeneous domain. Mathematical models of such problems are described by a nonlinear parabolic equation in the two-dimensional domain D: ∂u∂t−∇(ε(x)∇\ u)=r(x)(1−u)u,  x ∈D,  ∂u∂t−∇(ε(x)∇\ u)=r(x)(1−u)u,  x ∈D,  where u is the function of 2D coordinates xx and time t, r is the rate of reproduction and ε is the diffusion. This equation has certain initial and boundary conditions pending on the specifics of the problem. Here we have used a finite element method to solve this problem in the complex geometry with heterogeneous inclusions and implicit-explicit time approximation. Numerical implementation is performed by using python and finite-element library FEniCS. We have done numerical investigation of the influence of the geometry and heterogeneous properties on the solution.

Keywords: PARTIAL DIFFERENTIAL EQUATIONS, NONLINEAR EQUATION, FINITE ELEMENT METHOD, FENICS, NUMERICAL SIMULATION.

1 Department of Physical and Environmental Sciences, College of Science and Engineering, Texas A&M University- Corpus Christi

This study focuses on surfactants that contain hydrophobic tails based upon undecylenic acid and an amino acid such as alanine, S-aminobutyric acid, Norvaline and Norleucine as a hydrophilic headgroup. For these amino acid-based surfactants, various physical properties such as surface pressure and critical micelle concentration (CMC) are measured. In addition, thermodynamic parameters associated with micellization such as change in Gibbs free energy and change in entropy are calculated. Because the surfactants’ amino acids’ carboxyl groups are deprotonated at the studied pH, each surfactant is negatively charged; as such, counterions such as 1,2 Diaminopropane, 1,3 Diaminopropane, Ethylenediamine, and Sodium bicarbonate are added to stabilize the solution. The physical and thermodynamic properties for each surfactant are also measured and calculated with respect to each of these counterions. This is part of a broader study examining the physical properties of amino acid-based micelles.

Keywords: CONDUCTIVITY, TENSIOMETER, UNDECANOYL, MICELLIZATION

Department of Physical and Environmental Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi

Amphiphilic surfactants are the principal components of soaps and detergents which are responsible for their ability to lower the surface tension of water to and solubilize hydrophobic agents. Their actions in aqueous solutions are due, in part, to their ability to undergo a concentration dependent self-assembly process which leads to the formation of larger molecular ensembles called micelles. The self-assembly of these micellar aggregate superstructures is driven by the hydrophobic effect. In the case of charged amphiphiles, the size of the micelles formed is limited by the electrostatic repulsion that builds among contiguously assembled molecules that comprise the micelle itself. It is possible however to design amphiphile systems which employ molecular recognition motifs to order the self-assembly of molecules in a programmed manner. Towards this end, we have constructed a series of alkyl-bridged (5, 7, and 9 hydrocarbon chain) and glycol-bridged (tetraethylene glycol chain) bis-bipyridinium-based gemini amphiphiles. The bipyridinium units of these amphiphiles are strongly π-electron deficient and can form donor-acceptor π-π stacked charge transfer (CT) complexes with π-electron rich molecules in aqueous solution, in this case, the neurotransmitter melatonin. In this system, the π-electron rich donor molecular template, melatonin, serves as “molecular glue”, capable of decreasing the electrostatic repulsion among the charged assembled amphiphiles. The addition of the melatonin molecular template to solutions of the bipyridinium-based amphiphiles resulted in: 1) the formation of larger micelles; 2) a more thermodynamically favorable self-assembly process; and 3) an overall increase in the efficiency and effectiveness of the amphiphile to lower the surface tension of water. This supramolecular system was characterized by ¹H-NMR, ¹³C-NMR, UV-Vis spectroscopy and various 2D NMR techniques. The formation of CT complexes was confirmed by UV-Vis, 2D DOSY, and 2D ROESY NMR spectroscopies. This work augers well for further investigation into soft matter capable of undergoing template-directed self-assembly.

Keywords: HOST-GUEST INTERACTIONS, SUPRAMOLECULAR ASSEMBLIES, Π-ELECTRON DONOR-ACCEPTOR INTERACTIONS, STRUCTURE-PROPERTY RELATIONSHIP, VIOLOGEN DERIVATIVES.

¹ Department of Physical and Environmental Sciences, College of Science and Engineering, Texas A&M University- Corpus Christi; ², Department of Pharmacology and Molecular Sciences, School of Medicine, Johns Hopkins University; ³ Department of Chemistry, Carthage College

In this study, the critical micelle concentrations (CMCs) for 18 unique amino acid-based surfactant-counterion systems were determined using molecular modeling in silico. Two surfactant tails (undecanal, 10-undecenal) and three amino acid headgroups (the (L)-configurations of alanine, glutamic acid, and 2-aminobutyric acid) were combined using the AMBER 20 suite, creating a total of 6 unique monopeptide amino acid-based surfactants. These were combined with a set of three organic diamine counterions (1,2-diaminoethane, 1,3-diaminopropane, 1,2-diaminopropane) to form a total of 18 surfactant-counterion systems, which were solvated in water. The surfactant tails and counterions were defined by the general organic GAFF2 force field, the amino acid headgroups were defined by the specialized protein FF14SB force field, and the water molecules were defined by the specialized TIP3P water force field. For each surfactant-counterion system, the Packmol software package was used to create three cubic simulation boxes with a random distribution of surfactant, water, and counterion molecules beginning at a surfactant concentration of 60 mM, with a surfactant concentration decrement of -5 mM. For each surfactant-counterion system, three MD simulations are carried out at each surfactant concentration until micellar surfactant aggregation is observed. This concentration is reported as the CMC for each system.

Keywords: SURFACE ACTIVE AGENTS, PROTEIN SURFACTANTS, COMPUTATIONAL CHEMISTRY, THEORETICAL CHEMISTRY

1 Department of Physical and Environmental Science, Texas A&M University-Corpus Christi Life

Surfactants are being examined for many different fields such as chemical, medical, cosmetics, and pharmaceutical applications. Surfactants consist of two regions a hydrophobic and a hydrophilic region. The hydrophobic region is the head in most surfactants, while the hydrophilic region is the tail. Surfactants are dynamic molecules and able to form micelles. The micelles form when the hydrophobic region aggregates together and forms different shapes. The concentration at which micelles are formed is called the critical micelle concentration (CMC). The CMC is the lowest concentration needed for the surfactants to form micelles. Many different types of surfactants can be created. The surfactants that were examined consisted of dicarboxylated amino acid groups (glutamic and aspartic) with a 11 and 13 caron chain hydrophobic tails. The CMC of these surfactants were measured in presence of 1,2 diamino ethyl, 1,3 diaminopropane, 1,4 diaminobutane, 1,5 diaminopentane and 1.6 diaminohexane.  The effects of the different amino acids, tail structures, and counterions were tested by comparing the CMC values of the solution. The CMC was measured using the change in solution conductivity at different surfactant concentrations.  Preliminary results indicated that the hydrophobic chain length and the counterion type significantly effects aggregation behavior of the dicarboxylated amino acid surfactants in solution.   

Keywords: AMINO ACID, SURFACTANT, COUNTERIONS, CRITICAL MICELLE CONCENTRAION, CONDUCTIVITY, GLUTAMIC, ASPARTIC, AGGREGATION

Department of Physical and Environmental Sciences, College of Science and Engineering, Texas A&M University - Corpus Christi

With the increase of renewable wind and solar energy, there is a need for long-term, low-cost energy storage systems to buffer their variable output. Redox flow batteries (RFBs) have the potential to store large amounts of energy for on-demand power generation and long-duration discharge. RFBs consist of two soluble redox couples stored in separate tanks that are flowed through a stack during charge/discharge, decoupling the battery's power and energy capacity to meet custom scaling requirements. Despite this flexibility, RFBs currently have low energy densities compared to rechargeable lithium-ion batteries due to poor aqueous solubility of the active species and/or low voltage outputs. Robust, high voltage catholytes are needed in RFBs. The catholyte iron (II/III) tris-2,2’-bipyridine,

^2+/3+, has abundant elements, a high redox potential (~1 V vs. SHE), and is trivial to synthesize. However, its aqueous solubility is low (~0.1 M) and its charged form,

³⁺, dimerizes into a species,

²⁺, that delivers a low discharge voltage. In previous work, we boosted the solubility of

^2+/3+ with the use of isopropanol as a cosolvent. The research question addressed in this presentation is: how can the voltage output be increased? We discovered that the additive activated carbon cloth (ACC) increases the voltage output by up to 0.26 V. We hypothesize that the performance improvement is due to a catalytic mechanism. This presentation will demonstrate RFB battery performance using aqueous

^2+/3+ catholytes as a function of ACC loading, as well as half-cell electrochemical and spectroscopic experiments interrogating the apparent catalytic mechanism of ACC towards dimer reduction. Significantly, the findings show that activated carbon is a low-cost additive that makes redox flow batteries using abundant chemistries up to 12% more efficient.

Keywords: ELECTROCHEMISTRY, CATALYSIS, ORGANOMETALLIC CHEMISTRY

1 Department of Physical and Environmental Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi; 2

Marine dissolved organic matter (DOM) is a major carbon pool comparable to the atmospheric carbon pool and serves important roles in long term carbon storage. Elucidating the chemical composition of DOM is necessary to improve our understanding of its roles in global biogeochemical cycles. Most studies utilize solid-phase extraction (SPE) to concentrate and desalinate samples, followed by high-resolution mass spectrometry to characterize DOM composition. The conventional SPE method achieves up to 70% dissolved organic carbon (DOC) extraction efficiency; however sample acidification prioritizes the extraction of organic acids creating an incomplete chemical profile. Although a robust methodology, many compounds are not retained by the non-polar SPE resin constraining the analytical window creating a hidden fraction of DOM. This study aims to generate a method to elucidate the DOM fraction previously uncharacterized by targeting DOM constituents with basic functional groups. Surface seawater samples were processed by two distinct SPE procedures; the conventional acidified SPE procedure and the modified acid-free procedure. Extracts were analyzed with ion chromatography and liquid chromatography coupled to a high resolution, mass accuracy Orbitrap Fusion Tribrid mass spectrometer. Samples were analyzed by data-dependent acquisition in negative and positive modes, and databases were used for tentative structural identification of Individual DOM compounds. DOC extraction efficiencies of the acid-free SPE method were around 40%, even though it recovered lower DOC; still, it shows significant chemical composition differences relative to the conventional SPE procedure, indicating it extracts a distinct DOM fraction. These results suggest that utilizing both the conventional SPE procedure and the acid-free SPE procedure on seawater samples provide a more comprehensive chemical profile of marine DOM, overcoming the current bias towards acidic constituents. This method better represents marine water samples and has the potential to become a routine method for future marine DOM characterization.

Keywords: HIGH RESOLUTION MASS SPECTROMETRY, UNTARGETED MS, EXOMETABOLOMICS, SOLID PHASE EXTRACTION

¹ Department of Physical and Environmental Sciences, College of Science and Engineering, Texas A&M University - Corpus Christi; ² Department of Earth System Science, University of California – Irvine; ³ Department of Life Sciences, College of Science and Engineering, Texas A&M University - Corpus Christi

Radiocarbon (14C) measurements have been used to provide reliable age estimates extensively in the fields of climatology, atmospheric science, biogeochemistry, and paleoceanography. However, most radiocarbon data is generated by measuring a bulk sample (e.g., bulk sediments), averaging 14C content of all carbon (C)-containing organic compounds (after inorganic C removal) rather than the specific organic compound produced by the organisms of interest during their life. Compound-specific radiocarbon analysis (CSRA) of amino acids (AA) can thus be a useful tool to precisely determine the age when the AAs were produced by the organisms. Robust methods for CSRA-AA are not yet widely available, partly due to the relatively small amount of C in AAs. Here we present a new approach of CSRA-AA combining semi-preparative ion-exchange chromatography (IC) and Accelerator Mass Spectrometry (AMS). Phenylalanine (Phe), glutamic acid (Glu), and methionine (Met) with their corresponding blanks were separated and collected using the IC as individual fractions from a commercial AA mixture, followed by graphitization and AMS analysis for 14C measurements. Current blank contribution was 5.2 and 16.6 μg C with corresponding yields of 132 and 71.1 μg C for Phe and Glu respectively. The obtained fraction modern (FM) with blank subtraction and error propagation was 0.9937±0.0065 for Phe and 1.1362±0.0271 for Glu, which is in line with the modern origins of the AA standards (Phe: 1.0276±0.0017; Glu: 1.0293±0.0005). Initial result for 14C-free Met standard was 0.0108±0.0062 (FM) with a blank contribution of 12.3 μg C, consistent with its origin (0.0024±0.0005). The next step is to include additional AA standards and test real samples. Our ultimate goal is to conduct multiple-isotope measurements (13C, 14C, and 15N) of AAs preserved in sediments and separate the N cycling signals produced by surface plankton community from influences induced by diagenesis, microbial reworking, and horizontal transfer.

Keywords: CARBON ISOTOPE ANALYSIS, RADIOMETRIC DATING, AMINO ACID ISOLATION, CHEMICAL BIOMARKERS,ARCHEOLOGY

Department of Physical and Environmental Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi

The Boreal Summer Intraseasonal Oscillation (BSISO) is one of the most intense subseasonal atmospheric variations in the tropics. It is characterized by northward propagation over the northern Indian Ocean and western North Pacific, unlike the eastward propagating boreal winter Madden-Julian Oscillation (MJO). Previous studies indicate that the BSISO generates prominent anomalous surface winds and air-sea fluxes, particularly over the South China Sea (SCS). This study investigates the intraseasonal variability of the upper ocean in the SCS using satellite observations and high-resolution (1/12°) ocean reanalysis. Composite evolutions of Sea Surface Temperature, Salinity and Height (SST, SSS, SSH), and near surface currents associated with BSISO are constructed. Consistent with previous results, large intraseasonal SST variability associated with the BSISO is evident over the entire SCS in the satellite derived SSTs, which agrees well with those derived from high-resolution ocean reanalysis. In addition, the composite analysis of ocean reanalysis reveals prominent variability near the coast which is not well resolved by the satellite data. These include significant SST variability along the west coast of the Philippines and northwest coast of Borneo, which are associated with anomalous surface currents along the coasts. The subsurface variability associated with these SST anomalies is further discussed based on the analysis of ocean reanalysis.

Keywords: NA

¹Department of Physical and Environmental Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi

Dissolved organic matter (DOM) is a heterogeneous mixture of water-soluble chemical compounds. It contains organic carbon, nitrogen, and phosphorus from various biotic and abiotic sources with a wide range of chemical reactivities. DOM plays a vital role in many biogeochemical processes in estuarine sediments and is the largest reactive organic carbon reservoir across the Earth’s aquatic ecosystems. Even though coastal marine sediments are globally a significant source of DOM to the water column, their role in the marine DOM cycle is unclear because the transformation of porewater DOM that diffused to the water column remains largely unexplored. In this study, we investigate the changes in porewater DOM chemical structures during irradiation experiments. The samples were collected from six different stations from a semi-arid bay (Baffin Bay, Texas) on four different seasons. DOM sources of Baffin Bay are more dominated by phytoplankton/microbes and benthic fluxes than terrestrial sources. During all the irradiation experiments, we observed ammonia photoproduction (2-6µM). We analyzed porewater DOM using a state-of-the-art Orbitrap Fusion Mass Spectrometer coupled with both Ion chromatography and Liquid Chromatography. Preliminary structural elucidation results indicate that specific peptides and deaminated peptides with conjugated double bonds systems could lose their terminal amine functional groups as ammonia and break down into organic acids and free amino acids during irradiation experiment. This work highlights the critical connections between the marine water column and sedimentary carbon and nitrogen cycles. It will provide a better estimate of the nitrogen (N) loading to the coastal regions.

Keywords: MARINE SEDIMENTS, UV-VIS ABSORBANCE, LIQUID CHROMATOGRAPHY, ION CHROMATOGRAPHY, MASS SPECTROMETRY.

¹ Department of Physical and Environmental Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi, Corpus Christi, Texas, 78412; ² Department of Chemistry, Carthage College, Kenosha, Wisconsin, 53140

In this study, the effects of counterion type and surfactant-to-counterion ratio on the chiral selectivity of several binaphthyl derivatives with L,L- undecanoyl leucine-valinate was examined by use of Micellar Electrokinetic Chromatography (MEKC). The chiral separations of

by the dipeptide surfactant varied widely in the presence of three counterions, 1,2 diaminoethyl, 1,2 diaminopropyl, and 1,3 diaminopropyl and with surfactant-to-counterion ratios of 1-to-1 and 1-to-0.5. The results of this study have shown that the selection of 1,2 diaminoethyl in a 1-to-1 surfactant-counterion-ratio provides enhanced baseline separation for enantiomers of BOH in comparison to its 1-to-0.5 counterpart, though no significant difference in separation can be observed for enantiomers of BNP under the same conditions. Despite the observation that every one of the three included counterions engendered some degree of separation for each analyte, enantiomers of BNP exhibited heightened separation in the presence of 1,2 diaminoethyl and 1,2 diaminopropyl at a pH level of 8. Conversely, the comparative Na counterion separates enantiomers of BOH and BNA significantly better than the counterions examined.

Keywords: CHIRALITY, MICELLES, CAPILLARY ELECTROPHORESIS, ENANTIOMERIC SEPARATION

Department of Physical and Environmental Sciences, College of Science and Engineering, Texas A&M University-Corpus Christi

Seagrass populations are declining considerably due to anthropogenic pressures, such as nutrient loading into coastal waters. Excessive nutrient availability in these environments can induce eutrophication events that ultimately generate anoxia in marine sediments. This promotes the activity of anaerobic sulfate-reducing bacteria, which reduce sulfate (SO₄^2-) to hydrogen sulfide (H₂S) for energy production. When high levels of this bacterial activity persist, H₂S accumulates in the sediment. This small molecule can be highly toxic to living cells; yet, seagrasses appear to withstand relatively high concentrations of H₂S in their environments. The purpose of this study is to assess sulfide intrusion in the seagrass Halodule wrightii from various locations along the Texas Gulf Coast, and determine whether the uptake and distribution of sulfide-derived sulfur in H. wrightii vegetation differs between locations. Vegetation, sediment, and seawater samples were collected from three H. wrightii meadows within two estuaries near Corpus Christi, TX: two from the Upper Laguna Madre and one from Oso Bay. Root, rhizome, and leaf tissue from vegetation samples were separated, lyophilized, and homogenized into a fine powder. Sediment samples underwent a distillation procedure capable of liberating H₂S gas, which was precipitated as Ag₂S. Seawater samples were acidified and treated with BaCl₂ to precipitate seawater sulfate as BaSO₄. Tissue, Ag₂S, and BaSO₄ samples were analyzed for their sulfur stable isotopic composition by EA-IRMS. δ³⁴S values of H. wrightii samples taken from the Upper Laguna Madre, for all tissue types, were lower than those obtained for vegetation from Oso Bay, suggesting that the Upper Laguna Madre populations sourced more sulfur from sedimentary sulfide compared to the Oso Bay population. Results interpreted to date suggest a difference between H. wrightii populations from these two locations in sulfide uptake and assimilation, and allows for future research into the effects of local conditions on seagrass sulfur metabolism.

Keywords: SEAGRASSES, STABLE ISOTOPES, GULF OF MEXICO, MARINE SEDIMENT GEOCHEMISTRY

Department of Physical and Environmental Sciences, Texas A&M University - Corpus Christi

Solar and wind energy generation and their grid-scale integration are growing rapidly, however their efficient utilization is impeded by the intrinsic intermittency of these renewable energy sources. Aqueous organic redox flow batteries (AORFBs) employing synthetically tailorable organic electroactive compounds composed of earth-abundant elements have received significant attention for energy storage technologies for their low cost, safety, and tunable properties. A redox flow battery (RFB) stores its energy in redox-active materials dissolved in liquid electrolytes circulating between external reservoirs and the battery stack, gives rise to their main advantages of decoupled energy and power, and excellent scalability. Regardless of this, they are facing daunting challenges such as low utilization ratio, high system complexity, low solubility, insufficient lifetimes, and scale-up difficulties. Therefore, to achieve high-energy-density flow batteries, electrolytes with electroactive materials that have high concentrations, high redox potentials, and ultra-low-capacity fade need to be developed. The nitroxyl radical 4-hydroxy-2,2,6,6-tetramethyl­piperidin-1-oxyl (4-HO-TEMPO) and its derivatives has been evaluated as a cost-effective catholyte for AORFBs in pH-neutral supporting electrolytes. TEMPO compounds can operate at high current density (up to 100 mA cm⁻²) and deliver impressive cycling performance due to its considerable positive redox potential. However, imperfect chemical stability and capacity decay, which are exacerbated at high concentrations, are still unacceptably high for TEMPO species. The presented research highlights the possibility to enhance the longevity of (4-HO-TEMPO) at high concentrations when paired with 1,10-bis(3-sulfonatopropyl)-4,4′-bipyridinium (SPr)₂V anolyte. Moreover, this research is focused specifically how pH impacts redox reversibility, diffusion coefficient and kinetic rate constant by inducing or suppressing disproportionation of TEMPO and other side reactions. Herein we build upon recent progress with this promising catholyte species and improve performance by using buffers to maintain the pH of electrolytes to avoid degradation and thus high-capacity fade rates of TEMPO.

Keywords: ELECTROCHEMISTRY, ELECTROCHEMICAL REVERSIBILITY, ELECTROACTIVE COMPOUNDS, CHARGE-DISCHARGE CYCLE, ION EXCHANGE MEMBRANE

College of Science and Engineering, Texas A&M University-Corpus Christi

In the current global transition to renewable energy sources, large scale of energy storage technologies are needed. Solar and wind energy are available intermittently, thus there is a mismatch between energy production and societal demand. Redox flow batteries (RFBs) are an attractive energy storage option, as they can decouple capacity (tank size) and power (stack size) for installation at any scale. Furthermore, RFBs offer long operational lifetime and higher safety than other batteries such as lithium-ion devices. RFBs using earth-abundant elements (carbon, iron, etc.) are being explored as new, inexpensive active species, but these new materials require compatible electrolytes, long-term stability, high solubility and optimal reaction kinetics. This work studies RFBs using different supporting electrolytes to understand their effect on performance of the battery. In RFBs all active species are dissolved in liquid electrolytes which can affect their performance. Specifically, RFBs contain two electrolytes, anolyte and catholyte, which are comprised of the solvent (e.g. water), the redox active compound (e.g., Fe(bpy)₃²⁺ or anthraquinone-2,6-disulfonate AQDS), and a supporting electrolyte containing cations (Li⁺, Na⁺, K⁺, or NH4⁺) and anions (Cl^- or NO^3-). The electrolyte is pumped through an electrochemical stack where the active species are oxidized or reduced to charge or discharge the battery. This research project be quantifies achievable current densities, long-term capacity fade rates, as well as diffusion coefficients and reaction kinetics as a function of supporting salt identity.

Keywords: ELECTROCHEMISTRY, BATTERY LIFETIME.

¹ Department of Physical & Environmental Sciences, College of Science and Engineering, Texas A&M University - Corpus Christi; ² WB Ray High School, Corpus Christi, TX

The seagrass Halodule wrightii is a vital part of Texas Gulf Coast ecosystems. Genetic diversity is associated with many positive traits, and a decrease could result in a decline in the viability of the overall plant population. We examined genotypic diversity (R) in a population of Halodule wrightii from Oso Bay, Tx, and compared the results to those collected in 2017 and 2019 from the same location. Past results indicated low to moderate genotypic diversity in this population and a lack of an evident seed bank. In 2021, we were only able to collect samples from 25 out of 48 positions, representing a 49% loss of seagrass coverage since 2019. We found that, over this time period, 11 genotypes were lost, and 9 new genotypes were gained. The genotypic diversity estimate for 2021 (R = 0.25) was similar to that of 2017 and 2019 (0.22 and 0.24, respectively). Our results indicate that Halodule wrightii is able to maintain genotypic diversity over time, despite a significant decline in population size and lack of an evident seedbank.

Keywords: SEAGRASS, GENOTYPIC DIVERSITY, HALODULE WRIGHTII

¹ Department of Physical and Environmental Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi; ² Department of Life Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi

As a result of climate change induced stressors, such as changing weather patterns and frequency and intensity of disturbance, many ecosystems are experiencing regime shifts. Coastal saltmarshes along parts of the Gulf of Mexico are being encroached upon and associated plant species are outcompeted as populations of Avicennia germinans (L) L, the black mangrove, expand due to a decrease in freeze events. This study has two main goals: to investigate the difference in macroinvertebrate community composition, diversity, richness, and abundance in litter habitat between two dominant vascular plant species – the marsh forb Batis maritima L and the mangrove A. germinans – across a temperature and salinity gradient, and to investigate the effect of macroinvertebrate colonization on litter decomposition rates across a temperature and salinity gradient. We also aim to determine individual species that are key contributors to litter decomposition. We hypothesize that community composition, diversity, richness, and abundance will vary among litter type and sites, with the greatest difference between sites at each end of a thermal gradient. Additionally, we hypothesize that macroinvertebrate colonization will increase decomposition rates in high salinity areas. To test this, we will deploy mesh bags containing leaf and stem litter at multiple sites of varying temperatures and salinities along the Texas Gulf coast. Bags will be placed near the waters’ edge of the intertidal zone and will be retrieved at different time intervals and returned to the lab where litter dry mass loss will be determined, and macroinvertebrates sorted and identified to the lowest practicable taxonomic level. This study will take place from March 2022 – January 2023 and is significant due to the limited number of studies on shallow water macroinvertebrate communities in saltmarsh-mangrove ecotones as well as understanding the impact of regime shifts on macroinvertebrate communities.

Keywords: CLIMATE CHANGE, COMMUNITY ECOLOGY, MACROINVERTEBRATES, INTERTIDAL ZONE, MANGROVES

¹ Department of Life Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi; ² Fundación In-nova Castilla la Mancha, Toledo, España; ³ Fisheries and Oceans Canada, French Village, New Brunswick, Canada

The dispersal of individuals between populations is a foundational process to understand at the interface of ecology and evolution. Natal habitat is theorized to strongly influence the degree of dispersal expected. However, understanding the interaction between habitat and dispersal is difficult to study empirically, particularly in a single location where other environmental factors are held constant. Understanding how habitats influence dispersal is important not only for the foundational understanding of ecological and evolutionary processes but also as they relate to the design of marine protected area networks. Here we seek to understand how heterogeneity in habitat quality influences the dispersal dynamics of the common Caribbean reef goby Coryphopterus hyalinus as a model for other species with similar life histories. To understand the influence of habitat heterogeneity on dispersal first it is important to establish what features of the reef equate to greater habitat quality from the perspective of the previously presumed habitat generalist C. hyalinus. Adult C. hyalinus live in large shoals distributed across shallow coral reef ecosystems in greater densities in more complex, deeper reef areas at the margin of large sand patches. In Turneffe Atoll, C. hyalinus have an average dispersal distance of 3.1 ± 0.3 km with 95% of individuals dispersing less than 7.7 ± 0.65 km. However, spatially heterogeneous habitats are characterized by shorter mean dispersal distances, smaller dispersal spreads, and higher propensity for rare dispersal events. This observation has conservation implications for the design and futureproofing of network-based conservation designs which depend upon dispersal between individual nodes of the network for proper functioning. As anthropogenic climate change alters habitats and in the short-term leads to increasingly fragmented and heterogeneous landscapes these networks may no longer be sustainable given the shrinking of the dispersal spread of the species these networks are designed to protect.

Keywords: DISPERSAL KERNEL, HABITAT HETEROGENEITY, CORYPHOPTERUS HYALINUS, STRUCTURE-FROM-MOTION, MARINE PROTECTED AREA NETWORKS

¹ Department of Life Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi, ² Harte Research Institute for Gulf of Mexico Studies, Texas A&M University – Corpus Christi

Tidal inlets play an essential role in estuarine-dependent nekton recruitment by providing access to nursery habitats (e.g., seagrass meadows) from spawning grounds in the Gulf of Mexico. The Corpus Christi Bay region includes Aransas Pass, a historically large inlet, and Packery Channel, a smaller natural tidal inlet permanently reopened in 2005. The purpose of this study was to (1) determine whether there is a seasonal difference in species diversity between the Aransas Pass (large) and Packery Channel (small) inlets and (2) determine if the distance from the inlet has an effect on species diversity. Shannon diversity indices were calculated from juvenile nekton (fish, shrimp, and crab) species collected using epibenthic sled tows from eight seagrass meadow sites near Aransas Pass and four sites near Packery Channel across three primary recruitment seasons (fall, winter, and spring). There was no significant difference in species diversity between the Aransas Pass and Packery Channel inlet, though there was a significant difference among seasons. Diversity was significantly higher during the winter and spring recruitment seasons at both inlets compared to the fall. In addition, distance (2-10 km) from the inlet had no significant effect on species diversity regardless of the season. These findings demonstrate that despite differences in size and age, Aransas Pass and Packery Channel support equally diverse nursery habitats across a range of distances for estuarine-dependent nekton species.

Keywords: FISHERIES, LAGUNA MADRE, POST-LARVAL SETTLEMENT, ESSENTIAL FISH HABITAT, INGRESS

¹ Department of Physical and Environmental Sciences, College of Science and Engineering, Texas A&M University-Corpus Christi; ² Harte Research Institute, Texas A&M University-Corpus Christi

Tidal streams are dynamic, transitional systems that provide key habitat to many ecologically and economically important species. Currently, the Texas Commission on Environmental Quality (TCEQ) monitors tidal streams in Texas using only physicochemical parameters and lacks a standardized biomonitoring protocol. To address this gap in management tools, a multi-metric index of biotic integrity (IBI) was created to assess the condition of tidal stream nekton and benthic macroinfauna assemblages along the lower Texas coast. By identifying biotic metrics that are differently sensitive to anthropogenic impairment, the IBI synthesizes complex biological data into a practical management tool. To create the IBI, 15 sites were classified as having high (reference) or low (test) anthropogenic impairment based on surrounding land-use land cover, watershed population density, and historical conventional parameter concentrations for each tidal stream. During 2020 and 2021, sites were sampled for nekton, via seine hauls, and benthic macroinfauna, via benthic cores. Water quality, conventional parameter, and habitat measurements were also assessed during these sampling periods. Results show distinction between reference and test communities based on multivariate analyses. IBI metrics were derived from historical IBI studies and community analyses based on their ability to discriminate between test and reference conditions. Selected metrics included abundance of certain nekton taxa, abundance and biomass of benthic macroinfauna taxa, measures of diversity, and faunal functional groups. Refinements to the IBI should consider further regionalization based on coastal climate zone, assessing multiple sites per stream along the upstream-downstream salinity gradient, and incorporating long-term monitoring data. Once validated, the tidal IBI will enhance the TCEQ’s monitoring and management program by providing a standardized protocol to evaluate the biological communities in tidal streams and identify areas most in need of management attention.

Keywords: COMMUNITY ECOLOGY, ESTUARIES, RESOURCE MANAGEMENT

¹ Department of Life Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi; ² Texas A&M AgriLife Research Mariculture Laboratory – Corpus Christi 

The eastern oyster, Crassostrea virginica, is a valuable foundational species providing critical ecosystem services and an economically valuable fishery and aquaculture industry for the state of Texas. However, Texas' top commercial fishery will be threatened by population growth, coastal development, pollution, and flooding. In addition, these local threats will interact with global environmental changes, so it is vital to understand the species' specific stress tolerances and adaptive capacities. This Texas oyster population is divided into two genetically different sub-species found in the Northern and Southern regions of the state, with Corpus Christi Bay acting as the transition zone between the divergent populations. However, few scientific conclusions have been made regarding why there is such vast genetic variation between the two populations of oysters in Texas. Therefore, this project will characterize the individual tolerance thresholds of the genetically different sub-populations to a range of salinities under high temperature using an intermittent flow respirometry technique. The results of this work aim to help predict future risk and resilience of the South Texas oyster population dynamics, aquaculture production, and restoration of ecosystem services. The risk assessment created will contribute to the resiliency of Texas' coastal oyster reef habitats to climate change by filling the knowledge gap surrounding stress tolerances to dramatic salinity fluctuations and evaluating how the genetically different oyster populations will respond to interacting local and global stressors. 

Keywords: STRESSORS, RESILIENCE, ANTHROPOGENIC INFLUENCE, ECOSYSTEM SERVICES, CLIMATE CHANGE

¹ Department of Life Sciences, College of Science and Engineering, Texas A&M University - Corpus Christi; ² University of Florida; ³ C-Image, GoMRI

The king snake eel (Ophichthus rex), is a large, long-lived demersal predator and their distribution is limited to the Gulf of Mexico (GoM). King snake eels, like other ophichthids are data deficient, little is known about the O. rex biology. Eels were sampled throughout GoM (2011-17); eel tissues were prepared for sequencing using new molecular techniques resulting in robust ddRADseq SNP libraries. Genetic differentiation was estimated and new multidisciplinary approaches were used to explore large and fine-scale patterns of observed genetic connectivity. Previous studies of genetic connectivity in the Gulf of Mexico, have been limited to a few commercially important species and have been spatially limited to northern GoM (US). This study is unique, as it encompasses the entire species distribution and utilizes Gulf-wide fisheries-independent survey data (GoMRI 2011-2017). In this study we present evidence of large-scale population structure as reported in previous GoM connectivity studies and discuss potential drivers of fine-scale differentiation patterns within and among populations. Finally, this study explores potential implications for other fisheries-affected species and increases overall understanding of the underlying biology that drives observed patterns of genetic connectivity.

Keywords: ANGUILLIFORMES, FISHERIES MANAGEMENT, NEXT GENERATION SEQUENCING, GENE FLOW, AND CONNECTIVITY

Department of Mathematics and Statistics, College of Science and Engineering, Texas A&M University – Corpus Christi

The cyclical relationship of the Lotka-Volterra predator-prey model is a critical base component for expansion in the research field of mathematical modeling. Our study focusses on a species relationship, the blue striped fang blenny, and the lizardfish, that has not yet been analyzed in this capacity. Fang blenny are interesting as they have a distinct character of changing colors and are able to mimic different species of fish by changing color. Fang blenny as a predator mimics harmless cleaner wrasse, consumes a bite from its larger prey and retreats the safety of its den. Unfortunately for the Fang blenny, the lizardfish is not fooled, and a would-be predator can itself become the prey. This species relationship is being observed through modeling.

Keywords: PREDATOR PREY MODEL, MIMICRY, FANGBLENNY, CLEANER WRASSE, LIZARD FISH

Department of Life Sciences, College of Science and Engineering, Texas A&M University-Corpus Christi

During their early life stages, larval fish are vulnerable to a variety of physical, biological, and environmental processes. The ability of larval fish to successfully capture prey items affects their body condition, growth rates, and ultimately survivorship. Previous studies on the larval diets of M. undulatus collected from October to November 2017 at two distinct locations Galveston, TX and Corpus Christi, TX showed significantly different diets at the two locations at the family level taxonomic resolution of prey items. The goal of this study was to determine if the M. undulatus between the two locations also have a difference in condition and growth rates that may be related to differences in diets and localized prey availability. Larvae for this study were collected approximately two to two and a half months following Hurricane Harvey, which may have changed the water quality which affects the growth of larval fish. Therefore, this study will also assess differences in environmental parameters between the two locations to determine the potential effects of the Hurricane. For that otoliths were extracted from larval M. undulatus and use otolith increment growth analyses to investigate the differences in their growth rates. The samples were divided into different categories including catch date, size class, and catch site. The two size classes that the study focuses on are 5.0-6.99 mm and 7.0-8.99 mm. By extracting, mounting, polishing, and measuring the otoliths from the collected samples, we are able to determine the growth rate and the age of the fish and expect to see differences between locations that may be caused by diet differences and water quality.

Keywords: MARINE, LIFE SCIENCE, NUTRITION, OCEAN, FITNESS

¹ Department of Life Sciences, College of Science and Engineering, Texas A&M University-Corpus Christi; ² Harte Research Institute for Gulf of Mexico Studies, Texas A&M University-Corpus Christi

Sharks are vital predators that keep the ocean ecosystems balanced; yet the potential impacts of improper handling during recreational shark fishing can increase their vulnerability. Successful conservation includes the education and implementation of proper handling practices, which are known to greatly influence the survival of sharks after release. However, factors associated with handling practices in the shore-based recreational fishery, such as landing locations along the surf-beach gradient, have not been well studied. Texas has one of the largest shore-based shark fisheries in the United States and catch-and-photo release tournaments like Texas Shark Rodeo (TSR), provide a unique opportunity to collect long-term data on sharks landed in this fishery. The purpose of this study was to characterize landing locations of sharks in the recreational fishery to help inform mortality after release. From photos submitted by TSR by participating anglers, landing locations, which may serve as a surrogate metric for air exposure time, were classified into three different categories based on the sharks’ gill position in relation to the waterline: (1) shark landed on dry sand (no water near the gills); (2) shark landed in the surf zone (gills might be somewhat aerated with wave action); and (3) shark landed mostly in the water (gills mostly underwater and aerated). A total of 8,697 landed shark photos were submitted to TSR from 2014-2021, of which 36.2% were landed on dry sand, 60.5% were in the surf zone, and 3.3% were landed with gills remaining mostly underwater. The relatively high percentage of sharks landed on dry sand may increase shark mortality after release. These findings have important implications for conservation-oriented organizations like TSR, that encourage the best catch-and-release practices to maximize shark survival and highlight the need for accurate mortality estimates based on landing location.

Keywords: CITIZEN SCIENCE, ELASMOBRANCH, POST-RELEASE MORTALITY, LAND-BASED, GULF OF MEXICO

¹ Department of Life Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi; ² Department of Biology, College of Science, UTRGV – Brownsville

Vibrio parahaemolyticus is the leading cause of gastroenteritis worldwide, partly as a result of clonal expansion of the highly pathogenic O3:K6 serotype. Genomic analysis of environmental V. parahaemolyticus O3:K6 strains isolated from the Pacific Northwest (PNW) led to the discovery of a novel ecotype harboring a deletion of seven genes (VP1884 through VP1890), all of which have been found previously to be upregulated upon bacterial culture at cold temperatures. This is noteworthy because, in the PNW, the virulent O3:K6 has been displaced by the O4:K12 serotype as the principal cause of V. parahaemolyticus gastroenteritis, perhaps as a result of its inability to survive on ice upon seafood harvest. Allelic exchange with the lacZ reporter gene from V. cholerae and the tetR selection marker from pBR332 was employed to generate VP1884-VP1890 null clones in clinical V. parahaemolyticus RIMD 2210633 and BAA-238 strains to test the hypothesis that this set of genes affects bacterial viability at cold temperatures. The VP1884-VP1890 mutants grown at 10°C displayed impaired growth kinetics compared to their WT counterparts. Similarly, survival of the mutant strains at 4°C was severely affected compared to WT counterparts. The rationale for undertaking these experiments is to uncover the molecular underpinnings that reveal the comparative lack of gastroenteritis caused by O3:K6 serotype in the PNW compared to other locations worldwide. The significance of the project is global because favorable selection for temperature sensitivity in Vibrios is likely caused by environmental conditions but also by public health measures and seafood handling practices characteristic of the PNW.

Keywords: PACIFIC NORTHWEST(PNW),GASTROENTERITIS, COLD SHOCK

¹ Department of Life Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi; ² Department of Estuarine and Ocean Sciences, School for Marine Science and Technology, University of Massachusetts, Dartmouth; ³ Instituto Politécnico Nacional-Centro Interdisciplinario de Ciencias Marinas; ⁴ Laboratorio de Genética para la Conservación, Centro de Investigaciones Biológicas del Noroeste; ⁵ Department of Physical and Environmental Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi.

Photosynthesis by phytoplankton at the surface ocean fixes atmospheric carbon dioxide into organic matters that sink to the deep ocean in the form of particles. The composition and flux of particles could be affected by microbial degradation and consumption and repackaging by zooplankton. Within the oxygen deficient zones (ODZs), the zooplankton abundance is greatly reduced and oxygen is absent as electron acceptors for aerobic degradation of organic matters. Elevated biomass of zooplankton was found just below the lower ODZ boundary, presumably due to the higher availability of sinking particles for feeding. However, there is a lack of observations that could establish the link between sinking/suspended particles and zooplankton in the ODZs. A better understanding of sinking/suspended particles and zooplankton dynamics through ODZs is essential for evaluating the carbon export to the deep ocean, as ODZ is expected to expand due to the current warming climate. Sinking/suspended particles and zooplankton samples were collected at the eastern tropical north Pacific ODZ (14N, 104W) at various depths in December 2020. δ¹⁵N of phenylalanine (δ¹⁵N_Phe) and glutamic acid (δ¹⁵N_Glu), the canonical source and trophic amino acid, are analyzed to assess the N isotope baseline and trophic positions (TP_Glu-Phe) of these samples. δ¹⁵N_Phe and δ¹⁵N_Glu of surface suspended particles were 3.50‰ and 10.57‰ respectively, yielding a TP_Glu-Phe of 1.48 that indicates the input of both phytoplankton and zooplankton materials to the suspended particle pool. Little enrichment in ¹⁵N of Glu was found between the suspended particles collected from the surface and below the lower boundary of ODZ (~1‰). This suggests limited trophic processing of sinking particles through the ODZ before zooplankton disaggregates them into suspended particles below the ODZ, which is in agreement with the slower sinking flux attenuation rate previously observed in ODZs.

Keywords: BIOLOGICAL PUMP, ZOOPLANKTON, PARTICULATE ORGANIC MATTER, AMINO ACIDS, NITROGEN ISOTOPES

¹ Department of Physical and Environmental Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi; ² Department of Engineering, College of Science and Engineering, Texas A&M University – Corpus Christi

Recent studies reveal that biofilm can develop under severe flow shear (e.g. >10,000 s-1) and eventually becomes resistant to shear erosion. Additional anecdotal evidence suggests clear correlation between biofilm structure and its underlying substrate energy landscapes. In this study, we are to investigate systematically the effects of these two environmental factors on formation of SR-biofilm. Here, we present experimental techniques that combine a long-term ecology-on-a-chip (eChip) milli-/micro-fluidic platform to grow a live SR-biofilm and a digital holographic microscope (DHM). The newly improved eChip platform not only provides long-term well controlled environments to a live SR-biofilm but also allow DHM to track thousands of individual bacteria as they interact with the substrate. New milli-fluidics also enables the interchange of substrates (bottom wall) containing different energy landscapes (e.g. alternating hydrophilic-hydrophobic patterns). Model bacteria include E.coli.(AW405), P. aeruginosa (PAO1) and its 12 mutants. Apart from homogeneous hydrophobic and hydrophilic substates, six patterned substrates (i.e. hydrophilic micro-patches, microscale squares and stars, of 20um, 50um, 100um over hydrophobic background) are used. Interactions of bacteria with these substrates are conducted under two shear flow rates (0 &10ul/min). During each experiment, bacteria will be cultured in eChip platform and flow over the patterned substrates for observation. Thousands of individual bacteria are tracked simultaneously in 3D over 20min at 14.5 frames per seconds at 20X and subsequently 3D trajectories, from which changes of cell motility (swimming speed, reorientation motility, and their translational/angular dispersions) as well as their attachment rates, will be obtained. In this talk, we will first present the novel microfluidic approach and robust digital holography technique (recording & analysis) in measuring microbial motilities/particle mobilities, then followed by a kernel study of P. aeruginosa in quiescent fluid interacting with substrates.

Keywords: DIGITAL HOLOGRAPHIC MICROSCOPY, SR-BIOFILM, CELL-WALL INTERACTIONS

Department of Life Sciences, College of Science and Engineering, Texas A&M University - Corpus Christi

Vibrio vulnificus is a Gram-negative mesophilic bacterium that is halophilic and asporogenous. It belongs to the gamma Proteobacteria phylum and family Vibrionaceae. It lives in coastal and estuary environments, and between April and October, it reaches peak levels in the Gulf of Mexico. Various environmental conditions, such as temperature, salinity, and pH, influence the activation of virulence genes in Vibrio vulnificus bacteria. Some literature reports state that antibiotic resistance is increasing in Vibrio vulnificus. Curanderismo, a popular alternative medicine derived from Mexican culture, has been overlooked by scientific investigation and may be used in lieu of pharmacologic antimicrobial agents. This study looked at the antibacterial capabilities of 10 typical herbal treatments used to treat wounds and infections in south Texas. This study investigated the effects of active plant extracts on strains of Vibrio vulnificus by Kirby-Bauer disk diffusion susceptibility testing; and whether active plant extracts affected on quorum-sensing-regulated virulence traits which manifests as biofilm formation against strains of Vibrio vulnificus. Each plant's ethanolic tinctures were made and applied on blank diffusion disks, which were then dehydrated and tested for susceptibility to four strains of Vibrio vulnificus bacteria using Kirby-Bauer disk diffusion susceptibility tests: VV27562 ATCC (type strain) and three strains isolated from the Coastal Bend region, VVARA0040407-40, BS0607-5 and NB0507-7, were then analyzed in triplicate. In addition, cultures of the four strains were grown for 96 hours in minimal medium in vitro, then cultures were grown in the absence or presence of plant tinctures. Cultures were then stained with 0.4% crystal violet to determine biofilm formation. Among selected plants, six plant tinctures exerted significant antimicrobial effect against the four Vibrio vulnificus strains. Preliminary evidence suggested that there may be some effect of certain plant tinctures on biofilm formation. This project suggests a new alternative in Vibrio vulnificus treatment for potentially increasing antibiotic resistance against Vibrio vulnificus bacterial strains.

Keywords: ANTIMICROBIAL RESISTANCE, PLANT TINCTURES, ZONE OF INHIBITION, CRYSTAL VIOLET ASSAY

1 Department of Physical and Environmental Sciences, 2Center for Water Supply Studies College of Science and Engineering, Texas A&M University – Corpus Christi

NO_x (NO + NO₂) emission decreases urban air quality and its subsequent deposition can be a significant source of excess nitrogen loading to coastal waters. Photochemical reactions between volatile organic compounds, and NO_x in the atmosphere creates ozone (O₃). Previous studies suggest that the City of Corpus Christi is in a NO_x limited zone, so an increase in NO_x would lead to an increase in O₃. The first step to NO_x emission mitigation is to quantify the contributions of NO_x sources. This study uses stable isotope techniques to measure point and nonpoint NO_x sources in order to quantify three main NO_x sources in the Corpus Christi air shed: vehicular, biogenic, and industrial sources. Each of these sources have unique isotopic compositions or “source signatures”, specifically δ¹⁵N-NO_x values, which are different for each source and allow the use of isotope mixing models to determine source contribution. NO_x and NO₂ passive air samplers will be deployed at three City of Corpus Christi NO_x and ozone monitoring stations each month for one year and the nitrogen and oxygen isotopic composition (δ¹⁵N, δ¹⁸O) of each sample will be measured. The δ¹⁵N-NO_x value in ambient air, and the δ¹⁵N-NO_x values of the NO_x sources, will be applied to a Bayesian isotope mixing model to quantify source contributions. Limited preliminary data suggests that vehicular emissions is the main contribution, followed by industrial emissions, then biogenic. Results will help aid in the creation of an ozone action plan for the City of Corpus Christi.

Keywords: AIR QUALITY, AIR POLLUTION, EMISSION, ATMOSPHERIC CHEMISTRY, PHOTOCHEMICAL, AIRSHED

Department of Physical and Environmental Sciences, College of Science and Engineering, Texas A&M University –Corpus Christi

Humans over the years have contributed to the changes in sea water chemistry. These changes stem from human caused carbon dioxide (CO₂) releasing activities related to burning of fossil fuels, cement production, and land use changes associated with agricultural activities among others. From the beginning of the industrial revolution atmospheric CO₂ has increased from 280 ppm to the current 419 ppm. In the same period, global oceans have taken in 30% of the global emissions as dissolved CO₂ therefore playing a role in climate change mitigation. Increase in dissolved CO₂ causes ocean acidification (OA). In the northwestern Gulf of Mexico (nwGOM), a decadal acidification has been observed in the shelf-slope region. For coastal areas the short term and long-term changes in the carbonate chemistry vary by location and can be influenced by river input, water stratification, ocean currents, and biogeochemical processes (photosynthesis, respiration, carbonate formation and dissolution). Despite its ecological and economic significance, the Gulf of Mexico and its current OA conditions are still misunderstood. This preliminary master’s thesis research will focus on spatial and temporal changes of carbonate chemistry trends of the nwGOM with a goal to understand the regions carbon dioxide sequestration over the past 5-10 years. Open access data from the Gulf of Mexico and East Coast Carbon (GOMECC) cruises-2007, 2012, 2017 and 2021 have been employed to explore this question. These expeditions have supplied comprehensive measurements of all primary inorganic carbon system parameters in these coastal waters. In addition, automated devices such as gliders equipped with sensors also collected additional measurements.

Keywords: GLOBAL WARMING, ENVIRONMENT, COASTAL, MARINE LIFE

1 Department of Life Sciences, College of Science and Engineering, Texas A&M University - Corpus Christi; 2 Department of Physical and Environmental Science, College of Science and Engineering, Texas A&M University- Corpus Christi; 3 Department of Estuarine and Ocean Science, School for Marine Science and Technology, University of Massachusetts - Dartmouth

Glutamine (Gln) and glutamic acid (Glu) provide the first step of incorporating inorganic nitrogen (N) into cellular organic N in photoautotrophic primary producers. Both are present at higher concentrations than other amino acids (AAs). The N atom in cellular ammonia forms the amide group of Gln, which is subsequently used in producing Glu. Although Glu supplies the N for most other amino acids via transamination reaction, Gln and Glu interconvert with each other via α-ketoglutarate. We hypothesize that the δ15N of Gln’s amino-N (δ15N_Gln-amino), amide N (δ15N_Gln-amide), and intracellular ammonium have the same values under equilibrium conditions due to fast turnover. In addition, the amide-N of Gln provides N for the nucleobases and one of the sidechain N atoms in histidine. Thus, position-specific N isotope analysis of Gln will provide key information on AA and nucleotide biosynthesis in organisms.  To analyze the amino and amide N’s, intracellular Gln was extracted from lysed phytoplankton cells, separated, and collected by Ion-exchange Chromatography, then divided into two fractions. One sub-fraction was oxidized by hypochlorite, converting the amino-N to nitrite. All the nitrogen in the second fraction were oxidized to nitrate using persulfate with UV radiation. The nitrite or nitrate produced in the two sub-fractions will then be converted to nitrous oxide and analyzed using Purge-and-Trap Isotope Ratio Mass Spectrometry, yielding both δ¹⁵N_Gln-amino and δ¹⁵N_Gln-total. Using the mass balance, we then can calculate the δ15N_Gln-amide by subtracting the δ15N_Gln-amino from δ¹⁵N_Gln-total. We will compare the δ¹⁵N_Gln-amino and δ¹⁵N_Gln-total with the δ¹⁵N of intracellular ammonium in cultured phytoplankton to verify our hypothesis. This study will shed light on the δ¹⁵N patterns of Gln and other amino acids in different phytoplankton phylogenetic groups under various metabolic conditions, which will further advance the use of δ¹⁵N-AA patterns in trophic ecology and paleo-N cycle reconstructions.

Keywords: OCEAN CHEMISTRY, NITROGEN ISOTOPE RATIOS, AMINO ACIDS, TROPHIC ECOLOGY

1Department of Engineering, College of Science and Engineering, Texas A&M University – Corpus Christi, 2Department of Life Science, College of Science and Engineering, Texas A&M University – Corpus Christi

Atomic Force Microscopy (AFM) is a powerful tool that can resolve nanoscale cell surface features (e.g. receptors, channels) as well as perform the mechanical characterization of living cells and tissues. Anecdotal observations suggest that metastasized tumor cells bear their phenotypical “telltale” signatures in their membrane characteristics, i.e prostate cancer cells are often stiffer and more elastic than breast cancer. In this talk, we present a new methodology allowing us to quantify mechanical properties of cells through force-deformation relations (F-D curves) by nano-indentation, as well as develop a novel mathematical framework to quantify cell membranes’ viscoelasticity by performing Ting's integral over F-D measurements to differentiate cancer phenotypes. We have developed a custom-made flow cell that enables simultaneous microscopic observation and AFM experimentation. Three cell lines, prostate cancer (PC3), breast carcinoma (T47D), and lung a-carcinoma (A549), are used for this kernel study. Cells are split once reaching a confluence of 70% and a 10% dilution of cells are plated on 12 mm diameter wafer. After 24-hour growth, the plated slides are transferred to in-house flow cell containing the corresponding culture medium. With an integrated LED illuminator sealed within a polydimethylsiloxane matrix underneath the wafer, simultaneous observation of live cells can be achieved by an integrated upright microscope. Indentation measurements are conducted with a “wet” AFM. Gold coated probes (k=0.03N/m) are used to allow measurement on soft cell membrane. Differing from past studies, we probe the membrane with large indentation. Standard Linear Solid model are fitted over measurements to obtain viscoelasticity parameters. Preliminary results show distinctive hysteresis between loading and unloading of the membrane. It is also found that multi-power law model is more suitable for cancer characterization. Model parameters of three phenotypes show clear distinction and great potential to develop membrane viscoelasticity as a biomarker for cancer cell diagnostics and characterization.

Keywords: ATOMIC FORCE MICROSCOPY, CANCER DIAGNOSTICS, CELL MEMBRANE VISCOELASTICITY, NANO-INDENTATION, CIRCULATING TUMOR CELL, MULTI-POWER LAW RHEOLOGICAL MODEL

¹Department of Life Sciences, College of Science and Engineering, Texas A&M University-Corpus Christi; ²Department of Biology, College of Science and Engineering, Boston University

The coastal waters of Texas have dynamic environmental conditions and are heavily influenced by anthropogenic stressors, which are not conducive for corals. However, cryptic coral species (Astrangia poculata and Oculina diffusa) have been documented in this ecosystem, particularly within manmade channels on jetty rocks connecting the Gulf of Mexico and Corpus Christi Bay. This research explored the strategies that these corals utilize to survive with varying fluctuations in environmental conditions. Extensive in-water-field surveys were conducted in Packery Channel over one year to 1) identify observed corals 2) biologically characterize observed corals, 3) document environmental variability, 4) quantify zooplankton abundance, and 5) conduct coral tissue stable isotope analyses. Physical environmental data (e.g., turbidity, temperature, salinity, etc.) was measured weekly during each season (e.g., winter, spring, summer, and fall). Additionally, plankton abundance and diversity measurements were assessed within each season at the highest tide and the lowest tide of the full moon cycle. Corals were collected seasonally (total n=64). Results of this work revealed the species present are Astrangia poculata and Oculina diffusa and that these corals utilize both heterotrophy and autotrophy year-round to withstand extreme environmental conditions including large temperature (9.4-31.5°C) and turbidity (0-95.3 NTU) ranges. Stable isotope analyses suggest heterotrophy to be the dominant feeding mechanism year-round and autotrophy secondarily. Specifically, autotrophic contribution is more prominent during the summer and fall seasons than in the spring and winter seasons which correlates with the environmental data fluctuating the least in the summer and fall. Understanding the nutritional sources of corals in extreme environmental conditions could provide insights into potential phenotypic plasticity and adaptability to anthropogenic influence. Therefore, corals thriving in dynamic environments could provide researchers with the insight they need to understand coral adaptation amid rapidly changing environmental conditions. 

Keywords: AHERMATYPIC, INVERTEBRATE, MIXOTROPHY, SYMBIOSIS, APOSYMBIOSIS

¹ Department of Life Sciences, College of Science and Engineering, Texas A&M University - Corpus Christi; ² Texas State Aquarium, Corpus Christi TX 78402; ³ Cincinnati Zoo and Aquarium, Powell, OH 43065

Coral reefs are one of the most biodiverse and productive ecosystems on Earth and various methods are utilized to monitor and assess coral health. But there is not a standardized method for quantifying coral health for corals held in captivity in zoos and aquariums. Therefore, a health assessment card using coral color to non-invasively monitor coral health was developed with the Texas State Aquarium (TSA). To quantify coral health, individual corals of each species were photographed in a controlled environment to develop color profiles. Simultaneously, nondestructive measurements of “health” were assessed using Pulse-Amplitude Modulation Fluorometry. These photosynthetic efficiency measurements determine how efficiently the symbiotic algae provides energy to the coral host. This project successfully corresponded photosynthetic efficiency to coral color to develop a Coral Health Assessment Card for all species at TSA. By implementing a standardized assessment of coral health, TSA can effectively and rapidly assess the health of their corals improving overall coral wellness. Consequently, the results of this work support TSA’s mission to support wildlife conservation by promoting education and conservation of coastal and marine ecosystems through their interactive exhibits.

Keywords: PHOTOSYNTHETIC EFFICIENCY, SYMBIOSIS, CORAL WELLNESS

Department of Life Sciences, College of Science and Engineering, Texas A&M University-Corpus Christi

Bottlenose dolphins (Tursiops truncatus) are the only species of marine mammal residing in the Texas Coastal Bend and have been specifically identified as imperiled by the National Oceanic and Atmospheric Administration. It has been almost 40 years since research has been published on the local population of bottlenose dolphins. In recent decades, the Texas Coastal Bend has substantially expanded in industrial growth and the Port of Corpus Christi is the third largest port in crude oil exportation in the U.S.A. The Corpus Christi Shipping Channel is also undergoing continual dredging to widen and deepen the channel to attract more commercial and industrial developments. With increasing and rapid changes and associated threats, it is important to monitor the local population of bottlenose dolphins and quantify how they are impacted by anthropogenic disturbance to inform policymakers for conservation mitigation. The population abundance of dolphins inhabiting the Texas Coastal Bend was determined by counting the number of animals based on unique markings. Photographs were captured of the individually distinctive dorsal fins of dolphins from a research vessel during 45 survey days since 2018. Photographs were subjected to quality control checks, cropped, matched by a minimum of two researchers, and scored based on quality. Preliminary results show that the current population of bottlenose dolphins consists of over 1,300 individuals, indicating a substantial population growth from the 593 dolphins reported in 1983. Findings from this study and additional photo-identification surveys will provide insights on the stability of the population that can be used as baseline data for conservation, including if dolphins are year-round residents and frequently inhabit areas of high vessel traffic.

Keywords: POPULATION ABUNDANCE, BOTTLENOSE DOLPHINS, PHOTO-IDENTIFICATION, TEXAS

¹ Department of Life Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi; ² Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida

Artificial insemination is an important tool for conservation of endangered species and is highly reliant on access to high-quality sperm. Unfortunately, artificial insemination has had mixed success in different species, which may be due to collection and insemination of poor-quality sperm. Therefore, development of a novel technique to promote ejaculation of high-quality sperm is necessary to improve the success of future conservation efforts through artificial insemination. The purpose of this study is to develop an innovative tool that will function to improve the quality of sperm at the time of collection from animals in managed care. This biomimetic artificial vagina (BAV) is the first artificial vagina designed to mimic the natural shape and elasticity of biological tissue. Our BAV is designed to collect ejaculates from common bottlenose dolphins (Tursiops truncatus), which exhibit complex genital morphologies that have coevolved between the sexes. We hypothesize that the morphology of the vagina may play a role in stimulating the penis during ejaculation and will result in the production of higher quality ejaculates compared to traditional manual collection techniques. BAVs are created by coating vaginal molds made from post-mortem female dolphins with a soft, skin-like silicone. Ten adult male common bottlenose dolphins housed at aquaria around Florida and Texas are currently being trained to ejaculate into the BAV. We will assess sperm quality through examining the morphology and movement patterns of the sperm using computer-assisted sperm analysis software. The integrity of the sperm will be assessed using basic histochemical and microscopy techniques. We will compare the properties of the sperm collected using the BAV with sperm collected using traditional collection techniques to determine the impact of collection method on sperm quality. Our research has wide applications to conservation of terrestrial and marine endangered species through improving artificial insemination success.

Keywords: GENITAL EVOLUTION, REPRODUCTIVE BIOLOGY, REPRODUCTION

¹ Department of Life Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi

Texas tortoises are the only North American tortoise not receiving federal protection and due to life history traits of low fecundity and limited dispersal they are particularly susceptible to anthropogenically-mediated decline, such as the oil and gas exploration throughout their range. Not only do these disturbances fragment the habitat of the Texas tortoise and restrict their range, but they may also suppress immune function increasing their susceptibility to disease. Upper respiratory tract disease (URTD) has been detected in all desert tortoise species and may cause morbidity and mortality in infected individuals. However, there is limited data on the presence of URTD in Texas tortoises and whether anthropogenic stressors or biological factors influence disease dynamics, hindering development of informed management strategies and actions. Therefore, we propose to 1) test for presence of URTD casual agents across the range of the Texas tortoise in the U.S.A. and 2) assess whether tortoises are more susceptible to URTD based on biological characteristics and anthropogenic stressors. To ensure our survey efforts are as widely representative as possible, we have established a network of biologists and citizen scientists to aid in our efforts. We have created an outreach and communication system with protocols for submitting observation data and assistance with obtaining biological samples. We will collect blood samples from Texas tortoises and send plasma samples to test for both URTD causal agents (Mycoplasma agasizzi and M. testudineum). We will further collect geographic variables, such as distances to oil/gas operations and distances to road, biological data (age, sex, size, any clinical URTD signs) to understand if certain anthropogenic stressors increase the prevalence of URTD. This knowledge will aid in relocation efforts of Texas tortoises in proximity to oil/gas operations and increase our understanding of disease prevalence in the species.

Keywords: TESTUDINES, DISEASE ECOLOGY, MYCOPLASMOSIS, GOPHERUS BERLANDIERI

Department of Life Sciences, College of Science and Engineering, Texas A&M University - Corpus Christi

Common bottlenose dolphins (Tursiops truncatus) are an important bioindicator species of ecosystem welfare and sustainability and generate critical economic capital annually through ecotourism in the Texas Coastal Bend (TCB). The TCB stock of dolphins has specifically been identified as imperiled by the National Oceanic and Atmospheric Administration due to the number of anthropogenic and natural disturbances they encounter, and proactive monitoring of TCB dolphins is a current management priority. Recent economic growth has supported large-scale coastal infrastructure initiatives, including the imminent construction of desalination plants within the TCB. Because common bottlenose dolphins are highly vulnerable to salinity changes, which can lead to infectious disease and mortality, it is critical to determine baseline health and stress levels before the construction of desalination plants in order to monitor physiological changes post-construction and to inform policymakers of environmental impact. In this study, we will assess physiological stress and health conditions in TCB bottlenose dolphins using a novel approach system. A drone will be flown over dolphins to measure the prevalence and severity of skin lesions, which are an indicator of compromised epidermal integrity, for the first time from an aerial perspective. Blubber samples will be collected from the same dolphins using a remote biopsy technique to measure stress hormone levels; this study will be the first to validate aldosterone in the blubber of bottlenose dolphins. The baseline health and stress data collected will be used to directly measure bottlenose dolphin susceptibility to environmental disturbances and will assist in the preservation of marine life in the TCB.

Keywords: CROSSBOW, HYPERSALINITY, MARINE MAMMAL, STEROID HORMONE, UAV

¹ Department of Mathematics and Statistics, College of Science and Engineering, Texas A&M University – Corpus Christi

According to a previous study, wild pigs were responsible for over a billion dollars in damage to property and farmland. With high reproduction rates, wild pigs will continue to grow rampantly if no predator is able to control the population. Unfortunately, the mountain lion, an important predator for the wild pig, has been trophy hunted despite laws being in place against it. Because of how often they are hunted and their low reproduction rates, mountain lions have had their population growth stunted and cannot maintain the wild pig population. It is important to educate farmers and hunters of this to ensure that the wild pig population does not continue to get out of hand. With less hunting of mountain lions, the population can recover, and wild pigs will return to a sustainable level, decreasing the amount of property damage done. This research illustrates the mathematical modeling of both species and study various factors that impact the population.

Keywords: NA

1 Department of Life Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi; 2 Veterinary Education, Research, and Outreach Program, Texas A&M University; 3 Department of Physical & Environmental Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi

Coral reefs are the foundation to the social, cultural, and economic life in Hawaiʻi; however, these reefs have not escaped the conditions that have ravaged coral reefs worldwide. Along the east coast of Oʻahu lies Kāneʻohe Bay, which serves as a living laboratory with distinct difference in environmental gradients due to variation in circulation and residency times. Landward, there is a distinct gradient of cesspool presence and therefore a gradient of potential effluent intrusion and nutrient loading to these reefs. Together, these provide a unique opportunity to explore the impact of water quality and ongoing ocean warming on coral health, susceptibility and tolerance. This research investigates how temperature and nutrients influence the coral holobiont across a spatial and temporal environmental gradient. Pairs of known bleached/non-bleached corals were collected at two sites within Kāneʻohe Bay which encompass this spatial gradient in temperature and nutrient influence. Corals were then subjected to experimental treatments (Control, Nutrient, Heated, Heated + Nutrient) for one month. Measurements of bleaching were collected at the beginning, middle, and end of the experiment and coral subsamples were collected at the beginning and end of the experiment for subsequent metagenomics analysis. I hypothesize that (A) coral subjected to a combined increase in temperature and nutrients will experience higher levels of bleaching and lower levels of survivorship, (B) historically non-bleached phenotypes will show higher levels of survivorship than their historically bleached counterparts, and (C) there will be an observed shift in microbial community composition across corals due to these stressors. If validated, these findings will support that coral bleaching susceptibility is manifested throughout the coral holobiont and the physiological response to stressors such as temperature and nutrient loading can be better understood and potentially mitigated, therefore supporting reef resiliency and restoration in the face of climate change.

Keywords: SYMBIOSIS, ZOOXANTHELLAE, GENE SEQUENCING

¹ Department of Physical and Environmental Sciences, College of Science & Engineering, Texas A&M University-Corpus Christi; ² Harte Research Institute for Gulf of Mexico Studies, Texas A&M University-Corpus Christi; ³ Cooperative Institute for Marine and Atmospheric Studies, University of Miami

The Gulf of Mexico (GOM) is home to large shellfish populations, and the northernmost tropical coral reefs in the contiguous US. Despite this, the progression of Ocean Acidification (OA) in the GOM is still poorly understood as historical carbonate chemistry measurements are scarce. Based on carbonate chemistry and hydrographic data collected from 2007, 2017, and 2021, we derived multilinear regression models built upon relationships between commonly measured hydrographic properties (salinity, temperature, pressure, depth, or oxygen) and aragonite saturation state (Ω_aragonite) and pH. The resulting models robustly predict Ω_aragonite with R²>0.92, RMSE<0.07 and pH with R²>0.66, RMSE<0.30 for four different scenarios including different subsets of the data based on area and depth.

Keywords: CARBON CYCLE, MLR, DATA SCIENCE

1 Department of Physical and Environmental Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi, Harte Research Institute for Gulf of Mexico Studies; 2Texas A&M University – Corpus Christi, Harte Research Institute for Gulf of Mexico Studies

Urban and agricultural runoff, changes to land use patterns and other anthropogenic sources of pollution affect water quality. Water quality is a key factor in ecosystem health. While physical and ecological models of pollution have been widely used to determine water quality, there is a significant gap in the use of socioeconomic metrics in these models. Numerous studies have explored the effects and/or trends of impaired water quality on socioeconomic factors. However, less information is available on the impact of socioeconomic factors on surface water quality. This study conducted a literature review of commonly assessed human activity and socioeconomic variables associated with water quality and assessed the availability of data to quantify these variables. The intent of this review is to apply available evidence-supported data to two case studies in the Texas Coastal Bend: Baffin Bay and San Antonio Bay. From the literature, commonly used socioeconomic metrics include land use/land change, community type, demographics, and population density. Possible point sources of pollution that relate to socioeconomic factors identified were wastewater treatment facilities, stormwater drainage, mining and oil extraction operations, and product manufacturing/ chemical production. Furthermore, this presentation will provide a preliminary assessment of data sources, data gaps, and recommendations.

Keywords: IMPAIRED WATER, HUMAN BEHAVIOR, NONPOINT SOURCE POLLUTION, CLEAN WATER ACT 303(D)

¹ Department of Computing Sciences, Texas A&M University-Corpus Christi; ² Conrad Blucher Institute for Surveying and Science, Texas A&M University-Corpus Christi; ³ Department of Physical and Environmental Sciences, Texas A&M University-Corpus Christi

The combined effect of absolute sea-level rise (ASLR) and coastal subsidence has been long monitored via tide gauges (TGs), which measure sea-level rise relative to land-fixed benchmarks, referred to as relative sea-level rise (RSLR). The importance of TG observations lies in dynamically reflecting land-water interaction which also is shaping the coastal living environment. However, TGs are usually sparsely distributed along coastline, providing limited information about the spatial patterns and variability of RSLR. Thanks to emerging satellite geodesy technologies such as satellite radar altimetry (SRA) and interferometric synthetic aperture radar (InSAR), changes of sea surface height can be measured in the ocean and largescale high-accuracy land deformation can be estimated. This study combines ASLR data derivied from SRA with coastal land deformation derived from InSAR to estimate and map RLSR along coastline near Galveston, Texas, one of leading subsidence hotspots in the United States. Specifically, the radar altimetry product “MEaSUREs” from NASA’s Jet Propulsion Laboratory (JPL) was used to extract the time series of sea surface height anomalies for estimating ASLR rate. Meanwhile, the persistent scatter (PS) InSAR technique was utilized to generate land subsidence from Sentinel-1 data between 2017 and 2021. The RSLR map is generated by combining ASLR and InSAR data via designed grid pattern defined by geographic information system (GIS) analysis near the coastline. The performance of the RSLR grid map is validated through comparing against results obtained by TG measurements. This study hopes to provide improved capability for monitoring RSLR along coastline in response to increased demands for coastal resilience and sustainable development.

Keywords: COASTAL SUBSIDENCE, RELATIVE SEA-LEVEL RISE, TIDE GAUGE, RADAR ALTIMETRY, INSAR

¹ Department of Life Sciences, College of Science and Engineering, Texas A&M University-Corpus Christi

Port Corpus Christi and Port Aransas, Texas, have undergone considerable infrastructure and oil exportation growth over the past 40 years. As humans continue to transform and exploit these coastal marine habitats, understanding dolphin and vessel interactions in the area is vital to improve conservation and management practices. As dolphins increased diving intervals and avoidance behavior in the presence of vessels, protecting marine mammals in areas of high vessel activity is urgent. To test the hypothesis that the movement patterns and behaviors of free-swimming bottlenose dolphins (Tursiops truncatus) are altered by vessel presence and size

near Port Aransas, a shore-based digital theodolite is being used. Dolphin behavioral state

and movement

are analyzed in response to vessel activity. Distance between dolphin positions and habitat features

are being calculated in ArcGIS Pro. Large vessels may elicit social and travel behavioral states as dolphins rode on the bows of most large tankers and cargo carriers. Dolphins mill and forage along channel banks and near the ferry crossing, suggesting that physical structures of concrete seawalls and mixing currents from vessel activity are utilized by dolphins to capture prey. In the morning and afternoon, dolphins oriented along the channel perimeter against the current flow with no positional changes in movement, indicating that tides may influence this population’s movement and behavior patterns. Understanding behavioral associations with diverse microhabitats in the Port Aransas area is crucial to conserve critical environments utilized by dolphins.

Keywords: TURSIOPS, VESSEL ACTIVITY, BOW-RIDE, THEODOLITE

¹ Department of Life Sciences, College of Science and Engineering, Texas A&M University – Corpus Christi; ² Veterinary Education, Research, and Outreach Program, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University; 3 Harte Research Institute, College of Science and Engineering, Texas A&M University – Corpus Christi

Aureoumbra lagunensis forms persistent brown tide algal blooms that disrupt ecosystem processes through light attenuation, decreased oxygen availability, and reduced sediment stabilization. These disruptions have negative, cascading effects on the ecology and economy of coastal regions. Nearly four decades of research has explored the environmental and anthropogenic drivers of A. lagunensis blooms, yet previous research has not explored a bloom’s microbiome. Here, we present a holistic study wherein we characterized the water quality parameters and microbial consortia associated with a recurrent brown tide bloom, utilizing nearby non-bloom waters as comparison. Bloom waters were characterized by higher oxygen, pH, salinity, water temperature, chlorophyll a, and organic nitrogen and carbon concentrations. Variation in algal cell concentrations were explained largely through dissolved organic nitrogen, organic carbon, and oxygen. Several bacterial taxa were significantly more abundant in bloom samples: Alphaproteobacteria (Rhodobacterales; 8.41%), Gammaproteobacteria (Chromatiaceae; 2.11% & Alcanivoracaceaewere; 1.73%), and Cyanobacteria (Nostocales; 4.50%). Alphaproteobacteria and Gammaproteobacteria have the potential to mediate B-vitamin acquisition and supply of sulfur compounds, respectively, in addition to the supply of reduced carbon and nitrogen compounds through cyanobacterial bloom co-dominance. Additionally, conditionally rare taxa that comprised nearly 15% of the bloom community

may mediate organic compound degradation, vitamin acquisition, and algal pathogenesis. Collectively, these results confirm and expand understanding of bloom drivers and demonstrate that A. lagunensis blooms are colonized by a unique microbial consortium that likely plays a significant role in bloom dynamics. Although a small percentage of the bloom’s community, these low abundance organisms can contribute disproportionate effects to the ecosystem and therefore play an important role in regulating bloom dynamics.

Keywords: MICROBIAL ECOLOGY, 16S RRNA, HARMFUL ALGAE BLOOM, EUTROPHICATION

¹ Department of Life Sciences, College of Science and Engineering, Texas A&M – Corpus Christi

Since the last freeze in 1989, populations of black mangroves (Avicennia germinans) have rapidly increased throughout coastal Texas. Some sites are dense shrub thickets that reduce light penetration, lowering salt marsh abundance; large-scale ecological regime shifts along segments of the Texas coast. Two consecutive nights of below-freezing temperatures in Feb. 2021 provided an opportunity to study the effects of a catastrophic disturbance on the regime shift in Corpus Christi Bay. The freeze caused substantial adult Avicennia mortality. We are using observational data to test two hypotheses: 1) that recovery of mangroves will be faster on Mustang Island than on Ward Island because Mustang is nearer the Gulf of Mexico which may provide for more mangrove propagule colonizers from locations outside the bay and also may have been a little warmer due to thermal buffering by the Gulf. We established paired 3x3 m plots on each Island near the seaward edge of the intertidal vegetation and 5-10 m further inland. We quantified shrub mortality, survivor resprouting, seedling recruitment, and marsh cover by species. Data from October 2021 shows that there was adult shrub recovery via epicormic resprouting (34% on Mustang and 13% for Ward) and seedling recruitment in all plots, while marsh cover expanded in most plots possibly because of mangrove canopy reduction. Nine months post freeze Ward had mean = 1.16 (2.6 SD) total seedlings per m² and Mustang had a mean = 40.8 (22.8 SD) seedlings. In 2019, Ward had a mean = 5 (1.1 SD) seedlings per m² and Mustang had a mean = 4.3(1.1 SD) seedlings per m².

Keywords: FREEZE, MANGROVE, SALTMARSH, DISTURBANCE, CLIMATE CHANGE

Socio-Economics Group, Department of Physical and Environmental Sciences, College of Science & Engineering, Harte Research Institute for Gulf of Mexico Studies, Texas A&M University – Corpus Christi

Urbanization is a complex socio-economic process that transforms formerly natural areas into urban settlements. As of 2018, 55% of the world's population reside in urban areas. Urban expansion contributes to climate change by increasing the rate of greenhouse gas emissions and at the same time reducing carbon sinks. However, cities can be part of the solution to this global crisis, through adaptation and mitigation actions. The effects of climate change can be differentiated between coastal zones and inland. The impacts of it on coastal plains, such as exists in the Gulf of Mexico (GMx), might be especially harsh. Although coastal plains represent only 2% of the total land area in the world, approximately 13% of the world's urban population lives in these areas. Finally, there are various taxonomies of climate hazards for cities; among them hydrological. This work is focused on identifying what adaptation and mitigation strategies urban planners are using in the Gulf of Mexico cities in the face of climate change, specifically hydrological threats. A literature review on the relationship between climate change and coastal cities in the GMx is presented as part of the current doctoral project.

Keywords: URBAN PLANNING, PUBLIC POLICY, ECOSYSTEM SERVICES, NATURAL-BASED SOLUTIONS, MIXED METHODS