Research at CCS

Marine turtles are found across oceans worldwide and are important keystone species for marine ecosystems. They provide many essential benefits to seagrass beds, coral reefs and dune environments. Being a highly migratory species, they transport nutrients across vast distances, connecting ocean and coastal ecosystems. Sea turtles moving locations tend to accumulate diverse communities of micro- and macro-epibionts on their skin and carapace because of the large surface area and unique microhabitats. Microbial taxa and overall community composition may be indicators of the host's health and the health of the marine environment in which they have travelled. This research project aims to characterize and compare the microbial communities present on the skin and carapace of sea turtles admitted to participating rehabilitation facilities in coastal Texas. This non-invasive sampling will be done on patients admitted between spring/summer 2026, and later in the year if there are any cold-stun events, during the standardized intake procedure. Using the DNA/RNA Shield Collection Tube with Swab (2 mL), sterile swabs will be rubbed across designated areas of the carapace and skin for consistency. These swabs will be analyzed using DNA sequencing techniques to identify and profile microbial taxa as operational taxonomic units (OTUs). The two regions targeted are the 16S rRNA gene, used to identify bacteria, and the 18S rRNA gene, used to identify eukaryotic microbes such as fungi and protists. Sequencing will be carried out using an Illumina platform, and resulting sequences will be grouped and compared to known databases to determine the types and diversity of microbes present. Microbial community composition will be compared across turtle species, geographic region, and disease status (fibropapillomatosis (FP) positive or negative). If sampling permits, bacterial communities from turtles with visible FP will be compared to those without to evaluate any potential microbial indicators of disease. Multivariate statistical analyses will be conducted to test for differences in composition among groups. Results are expected to reveal distinct microbial community differences across turtle species, geographic region, and disease status. By examining variation in turtle-associated microbiomes across health conditions and environments, this study aims to improve understanding of host–microbe relationships in marine turtles and explore the potential of microbial communities as indicators of turtle health and marine ecosystem condition.

Coastal wetlands only make up 5-8% of the Earth’s surface, but they play a disproportionately important role in ecosystem services such as biogeochemical cycling, nurseries for marine species, and protection from storm surge. Fiddler crabs (Uca spp.) are a dominant component of marine wetland benthic fauna found in coastal wetlands around the globe. Fiddler crabs are intertidal detritivores that increase plant productivity by allowing water and oxygen to move down into the sediment when they burrow for shelter and mating, a process called bioturbation. Previous studies have found that they increase greenhouse gas emissions, such as carbon dioxide (CO₂) and methane (CH₄), when they move through the sediment. This study aims to quantify greenhouse gas fluxes released from individual fiddler crab burrows in relation to burrow size (volume and surface area) and activity (occupied versus unoccupied). Single PVC enclosures will be pushed into the sediment over a burrow opening and next to a burrow opening, acting as a control. Gases will be syringe-extracted from the burrow enclosure and stored for processing. Following this, a RALCAM borescope will be inserted into each burrow to identify whether a crab is active inside. Finally, polyester resin will be poured into each burrow, and once set, the burrow will be dug out to measure volume and surface area. CH₄ and CO₂ concentrations will be obtained in the lab using a 7810 LI-COR Trace Gas Analyzer. The biotic conditions that stimulate these emissions and the extent to which they offset carbon storage are poorly understood; I aim to fill this knowledge gap by quantifying the greenhouse gas emissions from the individual burrows. The expected outcome is that emissions will be positively related to burrow activity/size, but these releases will be limited by organic matter and decomposition rates.