남극 킹조지섬 마리안소만의 중형저서동물 군집구조

Abstract

The temporal dynamics of the meiofauna community in Marian Cove, King George Island, Antarctica were observed from March 7 to December 21 2007. Nine meiofauna taxa were found, with nematodes the most dominant group, making up 92.97% of the total meiofauna density, followed by harpacticoid copepods (3.18%). Meiofauna abundance ranged from 123 to 874 individuals per 10 <TEX>$cm^2$</TEX> (mean 464 inds.10 <TEX>$cm^{-2}$</TEX>), which is lower than that found in some polar and temperate regions. The lowest meiofauna abundance was found in the 26th April sample (III) and the highest meiofauna abundance was found in the March 23rd sample (II). There was no correlation between meiofauna abundance and season. The seasonal changes were likely caused by meltwater runoff, and there were the physical disturbances on the bottom sediment by huge iceberg. Biomass of meiofauna varied between 20.36 and 101.02 <TEX>${\mu}gC{\cdot}10\;cm^{-2}$</TEX>, and overall mean biomass was 54.17 <TEX>${\mu}gC{\cdot}10\;cm^{-2}$</TEX> during the study periods. More than 80% of meiofauna was concentrated in the upper 2 cm of the sediment, and density decreased with depth. The mean diversity index was 0.37, and the ratio between the abundance of nematodes: and harpacticoids (N/C) ratio ranged from 7.31 to 95.04 (mean 26.39). NMDS analysis divided the community into three groups: A (III, IV, V, VII, VIII), B (II, IX, XI, XII) and C (I, V, X). The results of ANOSIM and SIMPER analysis revealed significant differences in community structure among three groups and major contributed meiofauna taxon in grouping were nematodes and copepods. No significant correlations were observed between major meiofauna taxon and environmental factors. Thirteen species in 12 genera representing nine families of harpacicoids were recorded. Ancorabolidae was the most diverse family, and Heteropsyllidae was the most abundant. The correlation analysis between benthic harpacticoid copepods and environmental factors showed that some species were affected by water temperature, sediment temperature, salinity, chlorophyll a concentration, grain size of the sediments and heavy metal contents of the sediments. These data describe the usefulness of benthic harpacticoid copepods as biological indicator species in Antarctic regions.