Spring Student Research Symposium 2022
Permanent URI for this communityhttps://hdl.handle.net/1969.6/90409
The purpose of the symposium is to provide students (undergraduate, graduate, postbac) from participating colleges (Science and Engineering, Education and Human Development, Nursing and Health Sciences) with an opportunity to present their research and obtain feedback in preparation for participation in national and international conferences.
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Browsing Spring Student Research Symposium 2022 by Author "Bahr, Keisha"
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Item 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, KeishaCoral 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.Item Cryptic corals: Coral polyp size and biometry are indicators of feeding mechanisms(2022-04) Gates, Maryssa; Epps, Ashleigh M.; Bahr, KeishaReef-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.Item Impact of ocean acidification on montipora capitata growth(2022-04) TenBrink, Eleanor; Tripler, Abigail; McNicholl, Conall; Bahr, KeishaIn 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.Item Oysters holding their breath: Comparing methodology for measuring the physiological response of Crassostrea virginica(2022-04) Gomez-Rangel, Kate D.; Good, Alexandra; Matt, Joseph; Hollenbeck, Christopher; Bahr, KeishaIn 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.Item A risk assessment of genetically divided oyster populations in South Texas(2022-04) Good, Alexandra; Gomez-Rangel, Kate; Matt, Joseph; Hollenbeck, Christopher; Bahr, KeishaThe 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.