Feeding strategies and diet composition of four Antarctic cnidarian species

The diet of four species of Antarctic cnidarians, two hydroids and two anth ozoans, was investigated. One hydroid, Tubularia ralphii, and one anthozoan , Anthomastus bathyproctus, seem to basically consume zooplankton whereas t he other hydroid species, Oswaldella antarctica, has a diet mainly based on the fine fraction of seston. The last cnidarian investigated, the stolonif eran alcyonacean, Clavularia cf. frankliniana, feeds mainly on resuspended material. The wide range of diets of these Antarctic cnidarians indicates o pportunistic behaviour by feeding on different sources and taking advantage of the available food sources. Data related to low C/N ratios in the sedim ent and high NO2 concentrations in areas with dense communities of benthic suspension feeders, along with data on capture rates, lead us to hypothesiz e that these organisms play an important role in the recycling processes of organic matter in Antarctic benthic ecosystems.