ANIMAL TRACES ON A TIDAL FLAT IN HANGZHOU BAY, CHINA

Despite prevailing low salinity (S ranging from 1 to 10) of the Hangzh ou Bay, its extensive (up to 2 km wide) flats along the northern coast have a species-rich macrobenthic fauna of crustaceans, bivalves, gast ropods and polychaetes. These produce a variety of crawling, feeding, dwelling and resting traces, some comparable to those observed on the flats of Korea and Taiwan. The characteristic star-like feeding traces of the bivalve Tellina (Moerella) iridescens are described here for t he first time. Sediment reworking appears to be largely confined to th e surface layer. The burrow-inhabiting crabs are also mainly surface s ediment feeders. These Chinese flats lack organisms reworking deeper s ediment layers such as lugworms or callianassid crustaceans. As compar ed to the Wadden Sea, sedimentation rate is higher and subsurface sedi ment reworking less intense, resulting in relatively few bioturbation structures in vertical sections of the Hangzhou tidal flat sediments.