The role of crabs in the heavy metal flow of the estuarine ecosystem of yangtze river, china

摘要

Macrobenthos play a major role in material flow of the esturanine ecosystem. As a primary consumer, they accumulate more essential elements, such as zinc and copper, than the primary producers (plants) do. However, resulting from their complex mechanism of regulation and control on the non-essential elements. e.g., lead and cadmium, they do not always accumulate more contaminates. Small sized crabs seem to accumulate more non-essential elements than the large-sized ones. In the Yangtze estuary, zinc and copper are found bio-magnified on the food chains, but there are not significant evidence of the effects on cadmium and lead. Potentially hazardous elements in the macrobenthos are harmful to the organisms at the higher trophic levels, such as waders and man.