Soft bottom benthic communities under potentially anthropic and natural pressures in Terra Nova Bay (Ross Sea, Antarctica)

Benthic communities have a key function in the Antarctic marine ecosystem since they play a central role in the food web pathway and represent the main “environmental biological memory”. The goal of the study is to evaluate differences in macrozoobenthic community structure, along the Antarctic coasts of Tethys Bay (Ross Sea), potentially affected by two types of pressures: anthropic, due to the presence of a scientific station, and natural, due to the presence of a penguin colony. In the austral summer of 2017/2018 and 2018/2019, four sites were sampled in order to detect the effects of these two types of pressure (anthropic vs. natural vs. two control non-impacted areas). The Road Bay site, near the Italian Station, is rich in macro- and micronutrients and NO3− and Cd2+; the Adélie Cove site, characterized by organic loads from a close penguin colony, is rich in PO43−. Lower values of NO3− and PO43−, as well as Cu2+ and Pb2+ heavy metals occurred in control sites, between Road Bay and Adélie Cove. The benthic community showed different qualitative–quantitative dominances of species among sites, mainly at 50 m depth. The results clearly show the dominance of different opportunistic species of macrobenthos where penguins or humans’ presence occurred. Therefore, benthic communities may be considered good biological indicators of the overall environmental conditions.