A comparison of the ecophysiological response on copper in Baltic clams from different populations in Europe

Differences in performance and bioaccumulation of copper, metallothionein-like protein (MTLP) levels and resistance in Baltic clams, Macoma balthica, from Arctic, subarctic and temperate areas were determined during a stress period caused by starvation and exposure to copper. Although the conditions at the start were different, the losses of weight and mortality rates were in general comparable in clams from all areas. In contrast to expectation, the accumulation of copper in (sub) Arctic clams was much faster than in temperate specimens, whereas the level of MTLP in all populations hardly increased. Copper was primarily accumulated in insoluble form: MTLP has in clams no major role in copper sequestration. It is suggested that the differences in copper accumulation rates between populations might be related to genetic (racial) differentiation.