Heavy metal-induced changes in the feeding and burrowing behaviour of a Baltic isopod, Saduria (Mesidotea) entomon L.

The burrowing and feeding activity of the Baltic Sea scavenging isopod, Saduria entomon L., was investigated in order to demonstrate the possible effects of water-and sediment-bound heavy metals. Sediments contaminated by copper (10 μg g−1 dry sediment), cadmium (35 μg g−1) or iron (200 μg g−1) decreased the burrowing activity of Saduria entomon, and the same metal concentrations were avoided in situations where contaminated and uncontaminated sediments were present. Pre-exposure to these metals impaired the ability of the species to avoid contaminated sediments. The metal concentrations shown to affect burrowing in S. entomon are similar to the levels found in the contaminated estuaries of the Baltic Sea. Metal concentrations in water suppressing normal feeding were 100–10000 times higher than those found in the natural seawater. A seven-day exposure to 10 mg litre−1 Cu caused a reversible feeding suppression, while exposure to 200 mg litre−1 Fe gave rise to an irreversible decrease in feeding activity.