Spatiotemporal variability in archaeal communities of tropical coastal waters

Spatiotemporal variations in the archaeal community structure from four locations along the central west coast of India were analyzed by denaturing gradient gel electrophoresis (DGGE) profiling and sequencing of prominent bands on the DGGE gels. A total of 36 water samples were collected during pre-monsoon, post-monsoon and monsoon seasons from three depths (surface, mid-depth , and close to bottom ∼20 m). The community DNA extracts from these samples were subjected to DGGE analysis. The results of this study clearly indicate a significant difference in the community structure between sampling locations and seasons. Location-wise variation was more pronounced during pre-monsoon and post-monsoon seasons. During monsoon, however, the depth-wise variation was pronounced, suggesting monsoon influence on archaeal community structure. Sequencing of DGGE bands suggested the presence of marine group I and II archaea. Canonical correspondence analysis indicated that nitrate, nitrite and chlorophyll a were the significant explanatory variables responsible for > 60 % variation in archaeal community in these coastal waters.