PM07 Freshwater Bivalve Ecotoxicology
Exhibit Hall
8:00 AM - Monday, 10 November 2003
(PM136) Seasonal trends of oxidative stress in freshwater clams from lotic and lentic habitats.
Conners, D.1, Black, M.1, 1 The University of Georgia, Athens, GA, USA
ABSTRACT- Measures of oxidative stress in bivalves are often used as indicators of adverse effects in contaminated aquatic habitats because they respond to a variety of chemicals. However, natural environmental factors are also known to affect oxidative processes and this can alter the susceptibility of organisms to chemical stress, and confound attempts to identify causation at contaminated field sites. In this study, we evaluated the effects of temperature, dissolved oxygen and food availability on measures of oxidative (superoxide dismutase, catalase, glutathione, lipid peroxidation and DNA damage) in freshwater clams (Corbicula fluminea) collected from relatively pristine locations. Clams and water quality measurements were taken monthly for one year from three locations within lotic and lentic habitats. Seasonally, antioxidant enzyme activity (catalase) was lower in cold winter months and lipid peroxidation was higher. Superoxide dismutase activity was low in the winter and summer months, and peaked during times of reproduction (spring and fall). Glutathione concentrations were highest in the winter. By habitat, lentic clams had lower antioxidants (catalase and glutathione) and higher levels of lipid peroxidation than lotic clams. Evaluations of water quality data suggest that temperature, dissolved oxygen and food availability may play important mechanistic roles in mediating oxidative stress in freshwater clams. Overall, these data suggest that freshwater bivalves may be more susceptible to oxidative stress in the winter or when in hypoxic environments, and that temperature, dissolved oxygen and food availability should be measured in biological monitoring programs to assist in determining the etiology of any observed adverse effects.
Key words: oxidative stress, Corbicula , season, biomonitoring