Quantitative distribution and functional groups of intertidal macrofaunal assemblages in Fildes Peninsula, King George Island, South Shetland Islands, Southern Ocean

• A total of 34 macrofaunal species were identified in the intertidal zones around Fildes Peninsula, King George Island.
• Macrofaunal assemblages at sand-bottom sites belonged to one group while those at gravel-bottom sites were divided into three groups.
• Considering functional group of macrofauna, detritivorous and planktophagous groups had the highest values of abundance and biomass, respectively.
• The most important environmental factors correlated with macrofauna were contents of sediment chlorophyll a, phaeophorbide and organic matter.

To evaluate spatial distribution pattern of intertidal macrofauna, quantitative investigation was performed in January to February, 2013 around Fildes Peninsula, King George Island, South Shetland Islands. A total of 34 species were identified, which were dominated by Mollusca, Annelida and Arthropoda. CLUSTER analysis showed that macrofaunal assemblages at sand-bottom sites belonged to one group, which was dominated by Lumbricillus sp. and Kidderia subquadrata. Macrofaunal assemblages at gravel-bottom sites were divided into three groups while Nacella concinna was the dominant species at most sites. The highest values of biomass and Shannon–Wiener diversity index were found in gravel sediment and the highest value of abundance was in sand sediment of eastern coast. In terms of functional group, detritivorous and planktophagous groups had the highest values of abundance and biomass, respectively. Correlation analysis showed that macrofaunal abundance and biomass had significant positive correlations with contents of sediment chlorophyll a, phaeophorbide and organic matter.