Estuaries are key components of global ecosystems linking the lands and oceans and play a vital part in both economic and ecological aspects. Archaea are ubiquitous in terrestrial and aquatic ecosystems, and they are necessarily players participating global biogeochemical cycles. The current study offers comprehensive understandings of aquatic and sedimentary archaeal communities in the Pearl River Estuary (PRE), the Jiulong River Estuary (JRE), the Changjiang River Estuary (CRE) and surrounding coastal regions, with the focus of ammonia-oxidizing archaea (AOA) and Bathyarchaeota. Through the investigate of sedimentary archaeal community in the PRE, we found that Bathyarchaeota was the predominant archaeal phylum which was mainly partitioned by the salinity. In the CRE, multivariate ana...[ Read more ]

Estuaries are key components of global ecosystems linking the lands and oceans and play a vital part in both economic and ecological aspects. Archaea are ubiquitous in terrestrial and aquatic ecosystems, and they are necessarily players participating global biogeochemical cycles. The current study offers comprehensive understandings of aquatic and sedimentary archaeal communities in the Pearl River Estuary (PRE), the Jiulong River Estuary (JRE), the Changjiang River Estuary (CRE) and surrounding coastal regions, with the focus of ammonia-oxidizing archaea (AOA) and Bathyarchaeota. Through the investigate of sedimentary archaeal community in the PRE, we found that Bathyarchaeota was the predominant archaeal phylum which was mainly partitioned by the salinity. In the CRE, multivariate analyses suggested that the archaeal community compositions and distribution patterns were different in the sediments of hypoxia and non-hypoxia regions, while Thaumarchaeota and Bathyarchaeota were major community components. Besides, we observed that the ammonia oxidation in regions of these estuaries was mainly contributed by AOA, and the major AOA groups were identified. Moreover, a new AOA species was discovered in the JRE through metagenomics. The potential adaption strategies of AOA in the estuarine environments were uncovered through genomic comparisons. Furthermore, comparative analysis was employed to reveal the genomic differences among AOA dwelled in different estuaries, in order to better understand their distribution patterns, metabolic potentials, and evolutionary clues, which also highlights their unique niches in estuaries. Altogether, our study illustrated the detailed archaeal community in the three estuaries, and identified potential influencing factors for the distribution of archaeal community, which might enlighten subsequent studies by offering a comprehensive understanding of estuarine archaea.