2022 Spring Student Research Symposium Oral Presentation Materials

Permanent URI for this collectionhttps://hdl.handle.net/1969.6/90412

Browse

Now showing 1 - 20 of 30

Characterizing a live shear-resistant (SR-) biofilm and its interaction with substrates of varying energy landscapes by digital holographic microscope in eChip microcosm
(2022-04) Yi, Wenjun; Jalali- Mousavi, Maryam; Sheng, Jian
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.
Sinking/suspended particles and zooplankton interactions in eastern tropical north pacific oxygen deficient zone revealed by δ15n-amino acids
(2022-04) Lee, Charlotte; Mnich, Alanna; Catala, Fernando Contreras; García de León, Francisco Javier; Sánchez-Velasco, Laura; Baca, Jesus; McMullan, Esme; Mcallister, Marysa; Tran, Dat; Shaws, Catherine; Altabet, Mark; Zhang, Lin
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. 15N of phenylalanine ( 15NPhe) and glutamic acid ( 15NGlu), the canonical source and trophic amino acid, are analyzed to assess the N isotope baseline and trophic positions (TPGlu-Phe) of these samples. 15NPhe and 15NGlu of surface suspended particles were 3.50‰ and 10.57‰ respectively, yielding a TPGlu-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.
Comparing diversity of estuarine-dependent nekton between Aransas Pass and Packery Channel inlets
(2022-04) Kuntz, Joseph; Coffey, Daniel; Kaiser, Jeffrey; Williams, Jason; Stunz, Gregory
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.
Fingerprinting circulating tumor cell with characteristic membrane viscoelasticity by atomic force microscopy
(2022-04) Lopez, Kimberly; Tamuno, Sophia; Brzezinski, Molly; Martin, Leisha; Xu, Wei; Sheng, Jian
Atomic Force Microscopy (AFM) is a powerful tool that can resolve nanoscale cell surface features (e.g. re- ceptors, 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 mem- brane 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 differen- tiate 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 hys- teresis 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.
Corals in crisis: How temperature and nutrient fluctuations affect physiological responses of corals and their microbiome in Kāne’ohe Bay, Hawai’i
(2022-04) Ruben, Zoe; Pinnell, Lee; Abdulla, Hussain; Turner, Jeffrey; Bahr, Keisha
Coral reefs are the foundation to the social, cultural, and economic life in Hawai i; however, these reefs have not escaped the conditions that have ravaged coral reefs worldwide. Along the east coast of O ahu lies Kāne ohe 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 Kāne ohe 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.
Mapping relative sea-level rise with satellite geodesy along subsiding coast near Galveston, Texas
(2022-04) Qiao, Xiaojun; Chu, Tianxing; Tissot, Philippe; Louis, Jason
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.
Holistic investigation of a recurrent aureoumbra lagunensis brown tide bloom: Water quality parameters and microbial consortia
(2022-04) Bachand, Paxton; Powers, Nicole; Haye, Kenneth C.; Pinnell, Lee; Tominack, Sarah; Turner, Jeffrey; Wetz, Michael S.
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 con- centrations 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 Cyanobacte- ria (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 (𝑃 ℎ𝑦𝑐𝑖𝑠𝑝ℎ𝑎𝑒𝑟𝑎𝑒(2.02) 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.
Climate change adaptation and mitigation in cities of the Gulf of Mexico
(2022-04) Urrea Mariño, Ulsía; Yoskowitz, David
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.
Intramolecular N isotope analysis of glutamine in phytoplankton
(2022-04) Schiereck, Samantha; Lee, Charlotte; Mnich, Alanna; Baca, Jesus; Shaw, Catherine; McMullan, Esme; Mcallister, Marysa; Tran, Dat; Altabet, Mark; Zhang, Lin
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 subse- quently 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 -ketoglutarate. We hypothesize that the 15N of Gln’s amino-N ( 15NGln-amino), amide N ( 15NGln-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 hypochlo-rite, 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 15NGln-amino and 15NGln-total. Using the mass balance, we then can calculate the 15NGln-amide by subtracting the 15NGln-amino from 15NGln-total. We will compare the 15NGln-amino and 15NGln-total with the 15N of intracellular ammonium in cultured phytoplankton to verify our hypothesis. This study will shed light on the 15N patterns of Gln and other amino acids in different phytoplankton phylogenetic groups under various metabolic conditions, which will further advance the use of 15N-AA patterns in trophic ecology and paleo-N cycle reconstructions.
Responses of mangrove and salt marsh in Corpus Christi Bay after the Feb. 2021 hard freezes
(2022-04) Rivera, Phillip; Proﬀitt, Edward; Devlin, Donna
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 consecu- tive 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 Avi- cennia 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.
Carbonate chemistry trends in the northwestern gulf of Mexico
(2022-04) Kumbula, Nicole; Hu, Xinping
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.
A preliminary assessment and subsequent data evaluation of socioeconomic indicators of water quality
(2022-04) Kramer, Mary; Yoskowitz, David
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.
A study on effects of mountain lion predation on wild pigs
(2022-04) Trigo, Mariah; Shankara Narayana Rao, Bheemaiah Veena
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.
Physiological stress and health of dolphins in the Texas coastal bend
(2022-04) Guinn, Makayla A.; Orbach, Dara N.
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.
Can a multi-metric bioassessment tool be used to assess faunal communities in tidal streams along the lower Texas coast?
(2022-04) Neﬀinger, Lexie; Beseres Pollack, Jennifer; Palmer, Terry; Breaux, Natasha
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.
NOx source apportionment in a coastal urban air shed using stable isotope techniques
(2022-04) Shealy, Kaiya; Felix, J. David
NOx (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 com- pounds, and NOx in the atmosphere creates ozone (O3). Previous studies suggest that the City of Corpus Christi is in a NOx limited zone, so an increase in NOx would lead to an increase in O3. The first step to NOx emission mitigation is to quantify the contributions of NOx sources. This study uses stable isotope techniques to measure point and nonpoint NOx sources in order to quantify three main NOx sources in the Corpus Christi air shed: vehicular, biogenic, and industrial sources. Each of these sources have unique iso- topic compositions or “source signatures”, specifically 15N-NOx values, which are different for each source and allow the use of isotope mixing models to determine source contribution. NOx and NO2 passive air samplers will be deployed at three City of Corpus Christi NOx and ozone monitoring stations each month for one year and the nitrogen and oxygen isotopic composition ( 15N, 18O) of each sample will be measured. The 15N-NOx value in ambient air, and the 15N-NOx values of the NOx 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.
Use of multilinear regression for prediction of PH and aragonite saturation in the northwest Gulf of Mexico
(2022-04) Jundt, EvaLynn; Hu, Xinping; Barbero, Leticia
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 (Ωaragonite) and pH. The resulting models robustly predict Ωaragonite 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.
An innovative approach to improving artificial insemination success
(2022-04) Rich, Jacquline; Cowart, Jonathan; Orbach, Dara
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.
Determining the effect of variability on habitat quality on dispersal in a marine fish
(2022-04) Selwyn, Jason D.; Usseglio, Paolo; Hogan, J. Derek; Bird, Christopher E.; Magnuson, Sharon Furiness
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, partic- ularly 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 aver- age 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.
Texas tortoise task force: Collaborative networks to increase surveillance of disease in tortoises
(2022-04) Tleimat, Jacquelyn; McCracken, Shawn
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.

Browse

Recent Submissions