Spatial distribution of planktonic archaeal community in the coastal waters around Meishan Island in spring

Abstract:

[Objective] Marine planktonic archaea are the key drivers of biogeochemical cycling, but the knowledge about their horizontal spatial distribution characteristics in the coastal waters has not been well understood. In this study, we used the Meishan Island (closely connected to the land) as an example to study the horizontal distribution patterns of planktonic archaea in the transition zone between land and sea.[Methods] 16S rRNA gene amplicon sequencing was used to reveal the spatial distribution characteristics of planktonic archaea in terms of the distribution of dominant taxa, community composition variation, and the co-occurrence pattern of taxa in the lagoon (called Meishan Bay) and adjacent seawaters around Meishan Island in spring.[Results] The results showed that relative abundance of planktonic archaea in the whole prokaryotic community ranged from 0.6% to 26.5%, and the archaeal abundance in seaward waters was significantly higher than that in the lagoon. Planktonic archaeal communities were dominated by Thaumarchaeota Marine Group (MG) I and Euryarchaeota MGII. The composition of MGI taxa was relatively simple, while MGII taxa had relatively high phylogenetic diversity. The spatial distribution of archaeal communities was shaped by homogenizing dispersal, environmental selection, and undominated processes (including ecological drift), and environmental selection was mainly driven by suspended particle, nitrate, dissolved oxygen, water temperature and ammonium. The network analysis showed that MGI taxa commonly had negative correlation with Rhodobacteraceae taxa, while MGII taxa commonly had positive correlation with heterotrophic bacteria affiliated to the clades SAR11, SAR116, and SAR86.[Conclusion] This study preliminary revealed the spatial distribution characteristics and drivers of planktonic archaeal communities in the coastal waters around Meishan Island in the spring, expanding the understanding of the distribution patterns of archaea in the transitional zone between the land and ocean.

Key words:planktonic archaea;coastal waters;spatial distribution;co-occurrence network