Depth distribution of euryhaline halophilic bacteria in Suribati Ike, a meromictic lake in East Antarctica

Euryhaline halophiles grow over a wide range of salinity, from <3% NaCl (seawater equivalent) to >15% NaCl and even saturation level (about 30% NaCl). Several species of euryhaline halophiles occur worldwide, especially in marine environments and also in aquatic and terrestrial habitats of the Antarctic ice-free areas. A biogeographic view of Antarctic halophiles is that their migration among lakes on land is more difficult than in marine setting. Ponds and lakes on land may thus serve as “islands” which facilitate the selection and separation of unique species. We isolated euryhaline halophiles from the saline lake, Suribati Ike, near Syowa Station and placed them into seven groups, each demonstrating a clear depth-related distribution. Six of the seven groups probably represent new species of the genera Halomonas and Marinobacter. This result suggests that Antarctic saline lakes exhibit high selectivity of unique euryhaline halophiles and possibly of other microbial groups.