Invertebrate Lab

I study Atlantic horseshoe crabs, Limulus polyphemus, and the effect of blood volume reduction on their physiological behavior. This project reflects the blood harvesting that occurs to hundreds of thousands to over a million specimens per year for biomedical testing. This study aims to provide valuable insights into the sustainability of this practice and its potential impact on horseshoe crab populations.

My project is focused on understanding the driving factors of benthic invertebrate biodiversity patterns on urban structures around Tampa Bay. I am interested in filling in the gaps in knowledge surrounding urban marine communities and the interface between humans and nature.

For my thesis research, I will be studying the post-hatching life stages of cephalopods (paralarval and juvenile) in the Gulf of Mexico. I’ll identify specimens collected by the Southeast Area Monitoring and Assessment Program, then conduct statistical analysis to examine their distribution and how environmental factors affect their abundance. To analyze vertical distribution, I’ll split the paralarvae into groups based on the depth at which they were collected and use multidimensional scaling to test for the presence of unique species assemblages. I’ll repeat this process with the latitudinal collection locations to examine any differences between shelf and offshore species assemblages. The second portion of my research will use stepwise regression to determine which environmental factors have the greatest impact on paralarval abundance. For both aspects, I’ll also be calculating measures of biodiversity such as the Shannon-Weiner diversity index.

Despite the ecological importance of mesopelagic animal communities, little is known about their ecology. The hammerjaw (Omosudis lowii) is a mesopelagic fish found in temperate and tropical waters worldwide, including the Gulf of Mexico. Hammerjaws have distensible jaws and stomachs, allowing them to capture extremely large prey relative to their body size. They are severely understudied but are often observed with squids in their stomachs. To date, no scientific study has been done to determine their feeding patterns. To fill this knowledge gap, I will conduct a stomach content analysis (SCA) study using preserved hammerjaw specimens collected by Gulf of Mexico research cruises from 2011 to 2021. Using various statistical methods, I will combine the SCA findings with life stage, environmental, spatial, and temporal data to provide a better understanding of the distribution and feeding ecology of Gulf of Mexico hammerjaws throughout their lifecycles. Ultimately, my research will describe diet as a function of ecology and set a baseline for further research on hammerjaws and mesopelagic trophic interactions.

My master’s research will focus on Eastern oysters (Crassostrea virginica). I plan to collect samples from various coastal areas around Tampa Bay, particularly those that may see heavier boat traffic, bringing in more debris and theoretically more pollutants. I want to examine the amount of microplastics found in these animals and measure the overall water quality of the area (temperature, salinity, dissolved oxygen, nitrogen, turbidity, pH, etc.) I would also like to gather samples both in the summer and winter to compare seasonality. I would like to compare my findings to similar coastal areas with less traffic to see if there is a difference in micro-pollutants and overall water quality.

Chemical compounds related to oil spills such as polycyclic aromatic hydrocarbons (PAHs) and persistent organic pollutants (POPs) like pesticides such as DDT can accumulate and persist for long periods of time in the Gulf of Mexico. Exposure to these organic compounds can be harmful to organisms and humans. They can also bioaccumulate in higher trophic levels within the ecosystem. And since squid are a prey item for many species it’s important to discover to what level chemical compounds may or may not contribute to bioaccumulation in their consumers. The focus of my research is to investigate this question through the predator/prey relationship between squid and tuna in the Gulf of Mexico. I will identify and quantify PAH and POP levels in mid-water cephalopods (squid) and tuna from the Gulf of Mexico. Tissue samples of squid collected from research cruises as well as those found within the stomach contents of tunas and the tunas they were found in will be used for this study. Additionally, I hope to assist in the development of a method to identify toxic compounds related to microplastics in the tissues of these animals. My research will contribute to baseline data for selected cephalopod species in the region.

My master’s research is focused on studying the movement of the coastal fisheries squid Doryteuthis pealeii in the eastern Gulf of Mexico throughout its lifespan. I hope to be able to better define the migration patterns of this species through analysis of the carbon and nitrogen isotopes in its eye lenses. These isotopes are deposited within thin, concentric layers of crystallin proteins around the outside of the eye lenses as the squid ages. δ13C isotope ratios tend to show a correlation with depth and supporting primary producers, while δ15N isotope ratios can show a correlation with distance from the coast due to the type of nitrogen source to the food source. I also hope to be able to determine the ages of D. pealeii specimens through examination of their statoliths. Statoliths are small, hard components of the statocyst within cephalopods that form growth increments throughout the specimen’s lifetime. By comparing the age of each specimen to the number of eye lens layers they have, I will be able to determine how often this species deposits a new eye lens layer. The joint analysis of stable isotopes within each eye lens layer and the age of each specimen should allow me to analyze the migration patterns of D. pealeii throughout different stages in its life.

The purpose of my Master’s research is to compare the behavior of sea turtles in captivity. I am collaborating with aquariums in Florida to determine how species type, health condition, size of enclosure, length of rehabilitation, and time of day affect how turtles behave. The tool required for this type of study is an ethogram, which is a list of behaviors seen in an animal with detailed descriptions. My ethogram includes general states of the sea turtles including rest, swim, respirate, groom, and aggression with more specific behaviors within the states such as rubbing on rocks, sleep, diving, surfacing, and scratching face with flipper. The turtles range from one that has been in captivity for 45 years to several very short term turtles that have only been in rehabilitation for several weeks. The goal of my project is to see how differences between turtles can affect their behavior, and how that can be applied to future sea turtle rehabilitation.

In collaboration with the USF College of marine science and Texas A&M Harte Research Institute, my master’s project is researching PAH exposure on red snapper in artificial and natural reef sites found in the northwestern Gulf of Mexico. The objectives for this study are to measure and compare PAH concentrations between gender, tissues or matrices (liver, gonad, muscle, and bile samples), and habitat type (natural vs. artificial reef systems) from red snapper collected in the Gulf of Mexico. With the growing amount of oil rigs in the Gulf of Mexico, it is important to understand if these rigs are creating negative affects for surrounding marine life. Polycyclic aromatic hydrocarbons (PAHs) are environmentally persistent pollutants that are both anthropogenically and naturally derived. These pollutants are known to be associated with oil rigs with potentially negative effects due to increased exposure to the organisms that utilize these structures. Since red snappers have been known to be an important part of the fisheries due to their high abundance rate, understanding the potential affects of PAHs is important to help better manage these affects and protect the natural marine environment.

My Master’s research project is focused on Pteropods (pelagic marine snails) collected from the Gulf of Mexico by the DEEPEND project. Pteropods play an important role in the food web of the pelagic ecosystem and they are a good indicator for ocean acidification. My research will provide valuable information on their identification, diel vertical migration patterns, shell thickness, distribution and abundance in the Gulf of Mexico (GoM). Pteropods are sensitive to environmental changes, such as temperature, pH and salinity, and these environmental stressors affect their ability to produce their shell. The aim of this research is to examine and understand how they are affected by these environmental stressors in the GoM.

In collaboration with The Florida Aquarium’s Center for Conservation (CFC), my research is focused on the microbial community makeup, and the establishment of an average growth rate for Dendrogyra cylindrus, commonly known as the pillar coral. D.cylindrusis the only species in its genus and is classified as vulnerable by the IUCN Red List. This large scleractinian coral species forms tall vertical pillars, reaching up to 3 meters if undisturbed. Coral nurseries, such as the CFC “coral ark”, are progressing conservation and restoration efforts by growing and transplanting coral fragments. By looking at the resident microbiota of multiple D.cylindrusgenotypes this study can contribute to the establishment of a core microbiome for the species to be used as a baseline to determine if bacterial clade shifts occur during restoration efforts. This will also aid future efforts for the mitigation of coral disease as well as contribute to the continued development of conservation management and reef restoration practices.

As a research assistant in Dr. Heather Judkins’ lab, my efforts are focused on understand the pelagic ecosystem of the Gulf of Mexico (GoM) through the vertical migration and distribution of the highly important biomass of cephalopods and heteropod species (pelagic marine snails). Species of heteropods vertically migrate day and night from the mesopelagic (200-1000 m depth) to the epipelagic depths (0-200 m) to escape predation and feed. By considering the data collected from net catches we gain knowledge of species abundance, behavior, and impacts from the environment. These efforts will further establish means of evaluations of deep-ocean ecosystems to disturbance impacts and recovery estimations. I continue to become familiar with cephalopods of the GoM and western central Atlantic by identifying species, pulling tissue samples for genomic DNA sequencing, taking organism measurements, record photographs of specimens, and preserving samples for these and future projects.

My Master’s project is focused on the stable isotope analysis of squid eye lenses. The use of stable isotope analysis (SIA) can be used as a tool to identify trophic and migratory histories of animals. Stable isotope ratios of carbon and nitrogen trace pathways of organic matter among organisms. The variation of nitrogen isotopes (δ15N) is an indicator of the animals’ trophic level and prey while the variation of carbon isotopes (δ13C) can be used to identify a primary producer at the base of a food chain. More recently, eye lenses have been used as a successful means for identifying the stable isotope ratios of certain squid species. Squid lenses exhibit a layering of thin tissue. There is a chronological deposition of concentric layers to the lens as the squid ages. The center of the lens contains the oldest layer, and the youngest layers are on the outermost surface. The lens is made up of crystallin proteins, which are rich in both carbon and nitrogen, making the eye lens a suitable source for isotopic analysis of both δ15N and δ13C. The goal of my research is to identify the geographic migrations of Doryteuthis plei in the Gulf of Mexico. I plan to distinguish the migratory and spawning patterns of this species by comparing the variations of stable isotope ratios from their eye lenses.

My Master’s research is focused on intraspecies variation and population connectivity in deep-sea cephalopods, as well as linking taxonomic diagnoses with DNA barcodes. My objectives include: determining genetic diversity in deep-sea cephalopods at the species level, determining genetic connectivity in deep-sea cephalopods at the regional level across different stations in the Gulf of Mexico (GoM), and at the population level across disjunct basins (GoM and Northwest Atlantic Ocean). By studying these patterns in deep-sea cephalopods, my research will lend insights on gene flow patterns among cephalopod species in the GoM and Northwest Atlantic Ocean. It is imperative to understand the gene pool and genetic exchange of deep-sea cephalopods to determine if demographic independence exists among populations, and subsequently, assess their vulnerability to impact and recovery after disturbance.