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Short term exposure to elevated pCO2 and hypoxia affects the cellular homeostasis of grass shrimp, Palaemonetes pugio
Citation:
Enzor, L., E. Moso, C. Hankins, AND M. Barron. Short term exposure to elevated pCO2 and hypoxia affects the cellular homeostasis of grass shrimp, Palaemonetes pugio. Society for Integrative and Comparative Biology, San Francisco, California, January 03 - 07, 2018.
Impact/Purpose:
The interactive effects of low dissolved oxygen (hypoxia) and elevated pCO2 (acidification) on estuarine organism physiology are not well understood. This study aims to identify if grass shrimp, Palaemonetes pugio, are sensitive to the combination of hypoxia and acidification in local Pensacola estuaries. Shrimp were exposed to these stressors over 5 days and surveyed for mortality. Tissues were assayed to determine the cellular level effects of oxidative stress and disruption of acid-base equilibrium. This study will provide information on the short-term energetic expense of exposure to acidification and hypoxia.
Description:
Estuarine organisms are adapted to frequent changes in temperature, salinity, pH, and dissolved oxygen (DO) levels. The high productivity of an estuary contributes to large changes in environmental conditions, with organismal respiration enhancing hypoxic zones, and elevating pCO2 levels. The interactive effects of elevated pCO2 and hypoxia remain largely unexplored in estuarine organisms, therefore, we investigated how short term (5-day) exposure to the combined effects of elevated pCO2 (~1300 µatm) and low dissolved oxygen (~2mg/L) impacted the cellular homeostasis of three different life stages of grass shrimp, Palaemonetes pugio. We explored levels of oxidative stress by measuring protein carbonyl formation, and the subsequent antioxidant response using superoxide dismutase and catalase enzyme activities. We combined these values with measurements of carbonic anhydrase activity to discern how exposure to elevated pCO2 and hypoxia can alter acid-base equilibrium and enhance reactive oxygen species formation. The results from this study highlight the short-term energy costs associated with exposure to elevated pCO2 and hypoxia, and provide information on which life stage, embryo, newly hatched larvae, or adult, are the most susceptible to the interactive effects of these environmental stressors.