Meeting Abstract

91.11  Wednesday, Jan. 7  Surviving global change in polluted environments: Metal-temperature interactions in metabolic physiology of a marine ectotherm SOKOLOVA, I.M.; University of North Carolina at Charlotte isokolov@uncc.edu

The thermal environment plays a key role in the distribution of marine ectotherms through the direct effects on their physiology and indirectly affecting their susceptibility to other stressors. Our studies show that exposure to a trace metal, cadmium (Cd) sensitizes eastern oysters Crassostrea virginica to temperature stress, and vice versa. Cd exposure results in a significant increase in metabolic costs of basal maintenance in oysters, mostly due to the elevated costs of protein synthesis and expression of stress proteins. Combined Cd and temperature stresses lead to the reduced aerobic capacity of oysters due to the limitation of oxygen delivery systems, higher Cd sensitivity of mitochondrial function and a decrease in mitochondrial abundance. At moderate temperatures cell protection capacities are sufficient to minimize the negative effect of Cd exposure on oxygen supply systems, and the oxygen supply is sufficient to provide for elevated maintenance costs. With rising temperature, the synergistic effects of elevated temperature and metal exposure on aerobic metabolic machinery on one hand, and elevated costs of basal maintenance on the other, result in progressive hypoxemia and a mismatch between energy demand and supply. As a result, energy-dependent protective mechanisms (e.g., antioxidants, metallothioneins and heat shock proteins) fail leading to elevated mortality and whole-organism physiological stress. Such interactive effects of temperature and pollution stress can have important implications for survival of ectotherms in the face of the global climate change and anthropogenic pollution and must be taken into account in environmental risk assessment. Supported by NSF CAREER (IBN-0347238).