Meiofauna response to iceberg disturbance on the Antarctic continental shelf at Kapp Norvegia (Weddell Sea)

The impact of iceberg scouring on meiofauna communities. especially nematod es. was studied on the Kapp Norvegia shelf in the Weddell Sea. Antarctica. Three stations with different stages of recolonisation following scour were selected on the basis of seafloor video images, sediment characteristics a nd faunal occurrences. These stations comprised a fresh scour, an older sco ur. and an undisturbed control site where a sponge spicule mat covered the sediment with dense epifauna. Meiofaunal abundance and taxonomic diversity of meiofauna groups were significantly reduced in the fresh scour. The high est abundance and diversity were found in the older scour as compared with the undisturbed site. The abundance and diversity of nematodes also decreas ed due to scouring. The abundance in the older scour recovered to the level of the undisturbed site whereas the diversity remained low. Scouring also changed the nematode community structure, with the suborders Desmoscolecina and Leptolaimina as the most sensitive groups. In addition, scouring resul ted in the decrease of selective deposit feeders and the Maturity Index. Th e low diversity and the change in nematode generic composition in the older scour compared with the undisturbed site. despite the Complete recovery in terms of abundance, suggest that the deep continental shelf nematode commu nity in this area is sensitive to iceberg disturbance.