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ALTERATIONS IN THE ENERGY METABOLISM OF AN ESTUARINE MYSID (MYSIDOPSIS BAHIA) AS INDICATORS OF STRESS FROM CHRONIC PESTICIDE EXPOSURE
Citation:
McKenney, Jr., C. AND E. Matthews. ALTERATIONS IN THE ENERGY METABOLISM OF AN ESTUARINE MYSID (MYSIDOPSIS BAHIA) AS INDICATORS OF STRESS FROM CHRONIC PESTICIDE EXPOSURE. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-90/381 (NTIS PB91163949).
Description:
Various aspects of the energy metabolism of an estuarine mysid (Mysidopsis bahia) were examined for different life stages during a life-cycle exposure to the organophosphate pesticide fenthion. Dose-response relationships were developed for several metabolic rate functions (oxygen consumption and ammonia excretion) and their combined bioenergetic and physiological indices (K2 values and O:N ratios). Initial exposure to fenthion resulted in elevated respiration rates of juvenile mysids. s shown by lower net growth efficiency (K2 values), these increased metabolic demands reduced the amount of assimilated energy available for production of new tissue, resulting in retarded juvenile growth rates. :N ratios indicated that juvenile mysids primarily utilized lipid substrates as an energy source, but during maturation shifted to greater usage of naceous substrates. igher O:N ratios during maturation of fenthion-exposed mysids suggest greater reliance on the more energy-rich lipid substrates to support the elevated rates of oxidative metabolism resulting in less lipid material being available for gamete production. hese results, when compared with similar studies with two other pesticide classes, suggest that measurements of sensitive zooplankton populations (e.g. mysids) may be used as indicators or reductions in population performance from chronic exposure to toxic organics.