Coastal Oceanography
Characterizing cyanobacteria and toxin presence along the Pamlico River Estuary and Sound: water, oysters and blue crab.
The transfer of cyanobacterial toxins, specifically microcystins, to oysters and blue crabs has been verified at several sites across NC’s estuarine habitats, raising concerns about human shellfish consumption. Microcystins have been associated with liver toxicity and liver cancer in humans who may consume contaminated seafood. Research Project 1 aims to advance our understanding of harmful algal bloom dynamics and microcystin contamination in seafood, combining state-of-the-art in situ observing technologies and targeted field surveys. Determining the spatiotemporal extent of blooms, cell dispersal, and linkages to seafood contamination is meant to guide mitigation efforts, inform risk assessment and prediction, and aid animal and human health studies.
Sampling the Pamlico Estuary
We are characterizing the environmental conditions that lead to increased microcystin and cyanobacterial presence in Pamlico Sound to test the hypothesis that increases occur due to site-specific shifts in environmental and hydrological conditions (e.g., salinity, temperature), and will primarily be associated with increased hydrologic transport upriver following severe weather events. To document bloom events in real-time and guide toxin testing in water and animals in relation to freshening events and potential downstream transport we will deploy An Imaging Flow Cytobot (IFCB). This automated submersible imaging flow cytometer generates images of particles and algal cells in-flow taken from the aquatic environment and will be deployed in combination with in situ water quality sondes and in situ toxin tracking approaches to complement monthly sampling.
Quantifying Microcystin Contamination
We are quantifying microcystin contamination in shellfish to test our hypothesis that microcystin transfer to oysters and blue crabs is widespread and linked to downstream transport of cells and toxins. Shellfish from Pamlico Sound will be analyzed for microcystin body burdens and relationships with cyanobacterial abundance and toxin patterns in the surrounding environments and pertinent physicochemical conditions.
Characterizing Microcystin Transfer
We are characterizing the temperature-dependent kinetics of microcystin transfer and detoxification in oysters and co-occurring predator the blue crab. We will test the hypothesis that microcystin transfer from lower trophic levels (oysters) to higher trophic levels (blue crabs) represents a balance between bioaccumulation and detoxification (i.e., dilution) and that climate or weather-induced changes in temperature will affect future risks related to shellfish body burdens and hepatotoxic shellfish poisoning.
