AUTHOR=Wu Yu-Fan , Xing Peng , Liu Shuangjiang , Wu Qinglong L. 

TITLE=Enhanced Microbial Interactions and Deterministic Successions During Anoxic Decomposition of Microcystis Biomass in Lake Sediment

JOURNAL=Frontiers in Microbiology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2019.02474

DOI=10.3389/fmicb.2019.02474

ISSN=1664-302X

ABSTRACT=<p><italic>Microcystis</italic> biomass remineralization after blooming represents a hotspot of nutrient recycling in eutrophic lakes. Because <italic>Microcystis</italic> blooms are massively deposited on lake sediments, resulting in anoxic conditions, it is important to understand the response and role of benthic microbial communities during the anoxic decomposition of <italic>Microcystis</italic> in freshwater lakes. In the present study, we employed a microcosm method, combined with high-throughput sequencing, functional prediction, and network analysis, to investigate microbial succession during the short-term (30 days) anaerobic decomposition of <italic>Microcystis</italic> in a eutrophic sediment. Continuous accumulation of CH<sub>4</sub> and CO<sub>2</sub> and increasing relative abundance of methanogens were observed during the incubation. The microbial community composition (MCC) significantly changed after addition of <italic>Microcystis</italic> biomass, with a shift in the community from a stochastic to a functional, deterministic succession. Families, including <italic>Clostridiaceae</italic>, <italic>Rhodocyclaceae</italic>, <italic>Rikenellaceae</italic>, <italic>Peptostreptococcaceae</italic>, <italic>Syntrophomonadaceae</italic>, <italic>Lachnospiraceae</italic>, and <italic>Methanosarcinaceae</italic>, were predominantly enriched and formed diverse substitution patterns, suggesting a synergistic action of these family members in the decomposition of <italic>Microcystis</italic> biomass. Importantly, intense species-to-species interactions and weak resistance to disturbance were observed in the microbial community after <italic>Microcystis</italic> biomass addition. Collectively, these results suggest that the addition of <italic>Microcystis</italic> induce phylogenetic clustering and structure instability in the sediment microbial community and the synergistic interactions among saprotrophic bacteria play a key role in <italic>Microcystis</italic> biomass remineralization.</p>