Coding planktonic microbial community structure

Planktonic microbial community assembly is central to understanding biodiversity maintenance and nutrient biogeochemical cycling in aquatic ecosystems. However, the lack of directly quantifiable parameters to characterize community structure has constrained in-depth analysis of the underlying ecological processes. To bridge this gap, this study introduces a novel single-value index that characterizes community structure by assigning a unique rank to each possible theoretical community composition. The index was subsequently applied to a continental-scale dataset encompassing diverse planktonic microbial communities (phytoplankton, bacteria, archaea, fungi, and other eukaryotes) and associated environmental parameters to examine inter-taxa interactions and influencing factors. Based on this framework, bacteria and archaea appeared to occupy central positions in regulating planktonic microbial community dynamics. In addition, basic water physicochemical parameters (i.e., water temperature, pH, and dissolved oxygen) showed closer associations with community assembly compared to nutrients at the continental scale. The novel method developed in this work offers a robust tool for deeper exploration in microbial ecology and biogeochemistry.