DOES CHRONIC EXPOSURE TO ENVIRONMENTAL STRESS INCREASE EASTERN OYSTER (CRASSOSTREA VIRGINICA) RESILIENCE TO NEW STRESSORS?

Exposure to environmental stressors can result in alterations to animal physiology, metabolism, microbiome composition, and survival probability. However, we hypothesized that animals with chronic exposure to a multi-faceted stressor like habitat quality degradation may have a lower stress response when exposed to new stressors and harbor microbial symbionts that enhance resilience. To test this, we exposed oysters collected from two Virginia rivers, Hampton (low quality) and Lynnhaven (high quality), to acute thermal stress via rising water temperature in a 14-day aquarium experiment. Oysters (n=54 per river) were divided into control and hot treatments. Control tank water was maintained at 25°C – equivalent to river temperature, and Hot tanks began at 25°C and was raised 1.7°C Day^-1 for 6 days to reach a final temp of 33.3°C. Cortisol—a stress-related hormone—was quantified using an ELISA assay. Oysters from hot treatments, especially Lynnhaven, had higher cortisol concentrations indicating increased stress. Clearance rate, how quickly an oyster filters the water (a proxy for metabolic activity), was higher in Lynnhaven-Hot than Hampton-Hot oysters. Preliminary microbiome data shows that oysters living in degraded habitat (e.g., Hampton) maintain a more stable microbiome composition when exposed to a new stressor. Together our preliminary results suggest that chronically-stressed oysters may develop metabolic and microbiome strategies to increase their resilience to new stressors providing hope that oysters can persist as habitat quality decreases and temperatures rise.

Presentation Preference: Poster

Primary Presenter: Rebecca Goldman, Washington and Lee (rgoldman@mail.wlu.edu)

Authors:

Estelle Fisher, Washington and Lee University  (fishere25@mail.wlu.edu)

Joseph Reustle, Hampton University  (joseph.reustle@hamtonu.edu)

Kelly Bezold, Washington and Lee University  (bezoldk@wlu.edu)

Alicia Reigel, Washington and Lee University  (areigel@wlu.edu)