Enhanced food-chain transfer of copper from a diet of copper-tolerant estuarine worms

Abstract

The population of the infaunal, littoral polychaete worm Nereis (Hediste) diversicolor at the top of Restronguet Creek, England, an estuary with very high sediment concentrations of trace metals, is tolerant to copper. These worms accumulate abnormally high body copper concentrations in comparison to control worms (Blackwater Estuary, England), 68% of the accumulated copper being bound in metal-rich granules. We show that sufficient of the extra copper accumulated in Restronguet Creek N. diversicolor is trophically available to another polychaete worm, N. virens, acting as predator, and brings about high accumulated copper concentrations in the latter worm. Electron microscopy with microanalysis has shown that copper detoxified in Cu-rich granules in the Restronguet Creek worms passes through the gut of the predator without apparent change in elemental composition. The trophically available copper in the Restronguet Creek worms may be in soluble form or bound to other cellular material. Ingestion of the Restronguet Creek worms will deliver an extraordinarily high (and potentially toxic) challenge to predators, including fishes and birds, feeding on N. diversicolor.