Chemodiversity of Dissolved Organic Matter Is Governed by Microbial Biogeography in Inland Waters

Dissolved organic matter (DOM) is crucial for the carbon
biogeochemical
cycle and has a close link with microbiome in aquatic ecosystems;
however, the causal relationship between DOM and microbial diversity
in inland waters is not very clear so far. Therefore, a national survey
of China’s inland waters was conducted, and the DOM chemical
composition and microbial community composition were determined by
Fourier transform ion cyclotron resonance mass spectrometry and high-throughput
sequencing to clarify the abovementioned question. Here, we found
that DOM chemodiversity was governed by microbial community assembly
in inland waters, not vice versa. Under the control of microbial biogeography,
DOM chemodiversity showed a clear geographical distribution difference.
Water DOM chemodiversity was mainly constrained by bacterial and archaeal
community composition, whereas sediment DOM chemodiversity was mainly
controlled by eukaryotic and fungal community composition. In addition,
the sediment DOM chemical composition was also affected by the interaction
of different microbial groups between waters and sediments. The study
is the first to clarify the causal relationship and proposes a microbial
regulatory mechanism on the geographical distribution pattern of DOM
chemodiversity, thus further deepening the understanding of the DOM
biogeochemical cycle.