Pearl River Estuary sediments Targeted Locus (Loci)

Archaea are widespread and play an important role in the global carbon and nitrogen cycles. However, we still have limited knowledge about how the function of Archaea in varying habitats. The goal of this study was to examine the change in community structure of Archaea in the sediments collected from the lower Pearl River, its estuary, and coastal South China Sea in order to evaluate how archaeal ecological function changes along the salinity gradient. Pyrosequencing of the 16S rRNA gene of Archaea was performed on sediment samples from Feilaixia Dam to Wanshan islands, which have a salinity range of 0.11‰ to > 31.27‰. Methanogens like Methanoregula, Methanosaeta, Methanosarcina and ammonia-oxidizing Archaea like Nitrososphaera were abundant in freshwater sediments of the Pearl River whereas Methanococcoides and Nitrosopumilus were abundant in the estuary and coastal South China Sea. This study provides the initial observation of the changing archaeal community structure from the lower Pearl River, its estuary and coastal South China Sea, which will aid the understanding of ecological functions of Archaea in the dynamic continental margins such as the South China Sea.