Microbial communities and DOM

The microbial community is a fundamental component of aquatic ecosystems that exhibits extremely high genetic diversity and plays an essential role in global biogeochemical cycles. Deciphering the complex interactions between dissolved organic matter - microbe associations and their underlying mechanisms have attracted considerable attention in microbial ecology research. In particular, the contribution of stochastic and deterministic community assembly mechanisms remain unclear in complex aquatic ecosystems. Lakes present an excellent system for their study with clear boundaries and strong environmental gradients. We studed the degree of interaction between stochastic and deterministic processes and their relative contribution through the dissolved organic matter (DOM) composition and microbial community composition in six lakes over the productive season. Our results indicated that environmental differences strongly influence beta diversity, especially the diversity of DOM on molecular formula-level and microeukaryota. We demonstrated that deterministic and stochastic processes interact to shape microbial communities and that deterministic processes are more important than stochastic processes in regulating DOM composition in lakes during the productive season. Taken together, our research provides novel insight into DOM-microbe associations and the carbon cycle at multiple scales., which can improve our predictions about carbon turnover.