The Xiamen Symposium on Marine Environmental Sciences (XMAS 2025)

Planktonic archaea are widely distributed in marine ecosystems and are major components of the marine biogenic elements cycle. However, there is limited understanding about how archaeal community biogeography varies across environmental gradients, and how their abundance of different groups may be affected by climate change. Here, using 16S rRNA gene amplicon sequencing and quantitative polymerase chain reaction, we investigated the biogeography, co-occurrence relationships, assembly mechanism, and abundance distribution patterns of the planktonic archaeal community in surface water samples collected during August and September 2015 of the East China Sea (ECS). Our findings indicate that the correlations among planktonic archaeal community structure, community diversity, sub-network topological parameters, and environmental factors showed great heterogeneity when considering the effect of different water masses. The community assembly mechanism of planktonic archaea is mainly determined by stochastic processes, accounting for 87.98% of all processes. Among them, drift accounts for 71.88%, widely distributed among the sampling sites of different water masses, which is an important ecological process of phytoplankton community assembly. We then perform a machine-learning-based analysis of different groups’ archaeal abundance to extrapolate their impact on climate change. Our predictive model indicates that the heterogeneity of the spatial distribution of planktonic archaea may decrease from the present to the end of this century in extreme climate change scenarios. Partial effects analysis shows that MGI prefers moderate temperatures and low salinity, while MGII prefers low temperatures and high salinity, which is consistent with the distribution pattern we found across different water masses. This study expands the understanding of the community composition, assembly processes, co-occurrence patterns, and abundance distribution of the planktonic archaea from different surface water masses in the East China Sea, which will be helpful to explore the adaptation mechanism of planktonic archaea to different marine environments and evaluate the role of marine plankton archaea in biogeochemical cycles on a larger spatiotemporal scale in the future.
 

marine archaea, biogeochemistry, climate change, envrionmental ad