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The existence of egg banks not only ensures the survival of zooplankton through harsh periods, but could also affect microevolutionary dynamics. Whether zooplankton at high latitudes can build up an egg bank in sediments, as occurs at lower latitudes, is still unknown. The distribution and age of viable resting eggs of the calanoid copepod Boeckella poppei Mrázek in sediments of two small freshwater lakes on King George Island were determined by slicing sediment cores at 1-cm intervals. Most viable resting eggs were found near the sediment surface, with abundance sharply declining to very low values at the depth of 5 cm, although eggs were present as deep as 9 cm in the sediments of Yanouhu Lake. The egg abundances in Xihu Lake and Yanouhu Lake were estimated to be 9.2 × 10 and 7.2 × 10 eggs m, respectively. Pb dating indicated a relatively constant sedimentation rate (0.023 cm year) in Xihu Lake, which was used to estimate the mean age (46.8 year), the maximum age (195.7 year), and the mortality rate (1.64 % year) of resting eggs of B. poppei in Xihu Lake. The accumulation of resting eggs with long-term viability in sediments provided the first evidence for the existence of egg banks in two Antarctic maritime lakes. An egg bank may serve as an overwintering strategy for B. poppei in Antarctica, enhance their ability to cope with random extreme changes, and contribute to their broad distribution. [ABSTRACT FROM AUTHOR]

Bacterial diversity was investigated in soil samples collected from 13 sites around the Great Wall Station, Fildes Peninsula, King George Island, Antarctica, using denaturing gradient gel electrophoresis (DGGE) of 16S rRNA genes. The classes α-, β-, and λ-Proteobacteria, as well as the phylum Actinobacteria, were found to be the dominant bacteria in the soils around the Great Wall Station. Although the selected samples were not contaminated by oil, a relationship between soil parameters, microbial biodiversity, and human impact was still seen. Sample sites in human impacted areas showed lower bacterial biodiversity (average H ′ = 2.65) when compared to non-impacted sites (average H ′ = 3.05). There was no statistically significant correlation between soil bacterial diversity and total organic carbon (TOC), total nitrogen, or total phosphorus contents of the soil. Canonical correlation analysis showed that TOC content was the most important factor determining bacterial community profiles among the measured soil parameters. In conclusion, microbial biodiversity and community characteristics within relatively small scales (1.5 km) were determined as a function of local environment parameters and anthropogenic impact. [ABSTRACT FROM AUTHOR]