A preliminary study of freshwater meiofaunal communities at Greenwich Island, South Shetland Islands, Antarctica

Meiofaunal communities of three small, shallow freshwater habitats sampled during the austral summer of 2013 in Greenwich Island, South Shetland Islands, Antarctica, are reported. Communities are dominated by tardigrades(85%), nematodes(11%), and rotifers(3%). Collembola, Oligochaeta, crustacean larvae(nauplii) and unidentified organisms account for 0.3%. Total meiofaunal densities reach 11 770 ind·cm-2, with mean densities(ind·cm-2) of 1 365.83 ± 2 716.65(Zone A), 523.67 ± 1 166.48(Zone B) and 72.17 ± 110.78(Zone C). Given the age of freshwater habitats, and the general lack of higher-trophic level predatory taxa, those species we report are likely early stage colonizers, and these communities are at an early stage of ecological succession. Non-parametrical analysis revealed the main variables influencing meiofaunal density and distribution are related to granulometric characteristics of sediments and microphytobenthic biomass. There were close relationships between meiofaunal abundance and microphytobenthic biomass, which indicates that benthic microalgae significantly influence meiofaunal distribution. A strong correlation between nematode abundance and the percentage of silt, clay and carbon in the sediment was also shown by canonical correspondence analysis and Spearman rank correlation.