Role of meteorological events on the ­macrofauna community and sediment ­composition of the shallow waters of martel inlet (Admiralty Bay, Antarctica)

Abstract

The short-term variability of the benthic macrofauna community in the shallow coastal area off the Brazilian Antarctic Station Comandante Ferraz (EACF) was investigated during the austral summer of 2008. Three replicates of sediment samples were obtained by a van Veen grab (0.0275 m²) at 20 m depth, in six periods from 1 st February to 7 th March. Macrofaunal densities and sediment composition varied during this period and were correlated to the wind field. Annelids (Polychaeta and Oligochaeta) were the most abundant group with density values ranging from 202 ind.0.0275m-² to 330 ind.0.0275m-² followed by Mollusca and Crustacea. The Principal Component Analysis (PCA) showed that the main sediment components that distinguish the samples were the percentage of gravel, silt and clay. These variations may be influenced by many factors and the climatic conditions play an important role in the local hydrodynamics that affect the benthic community, mainly the organisms with swimming capacity. Meteorological events may influence differently the sediment composition and the macrofauna community. Additional analysis is ongoing to better understand the short-term variability of the macrofauna, including the identification of the polychaetes. Moreover, studies concerning the local hydrodynamics and the interaction between wind, water and sediment in Admiralty Bay are needed.