Tissue Accumulation and the Effects of Long-Term Dietary Copper Contamination on Osmoregulation in the Mudflat Fiddler Crab Minuca rapax (Crustacea, Ocypodidae).

We examined copper accumulation in the hemolymph, gills and hepatopancreas, and hemolymph osmolality, Na and Cl concentrations, together with gill Na/K-ATPase and carbonic anhydrase activities, after dietary copper delivery (0, 100 or 500 Cu µg g) for 12 days in a fiddler crab, Minuca rapax. In contaminated crabs, copper concentration decreased in the hemolymph and hepatopancreas, but increased in the gills. Hemolymph osmolality and gill Na/K-ATPase activity increased while hemolymph [Na] and [Cl] and gill carbonic anhydrase activity decreased. Excretion likely accounts for the decreased hemolymph and hepatopancreas copper titers. Dietary copper clearly affected osmoregulatory ability and hemolymph Na and Cl regulation in M. rapax. Gill copper accumulation decreased carbonic anhydrase activity, suggesting that dietary copper affects acid-base balance. Elevated gill Na/K-ATPase activity appears to compensate for the ion-regulatory disturbance. These effects of dietary copper illustrate likely impacts on semi-terrestrial species that feed on metal-contaminated sediments.