Joint International Research Laboratory of Global Change and Water Cycle, State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing, 210098, China.
Laboratory of Molecular Bacteriology (Rega Institute), Department of Microbiology, Immunology and Transplantation, KU Leuven, Leuven, Belgium.
Microb Ecol. 2022 Aug;84(2):336-350. doi: 10.1007/s00248-021-01878-6. Epub 2021 Sep 28.
At certain nutrient concentrations, shallow freshwater lakes are generally characterized by two contrasting ecological regimes with disparate patterns of biodiversity and biogeochemical cycles: a macrophyte-dominated regime (MDR) and a phytoplankton-dominated regime (PDR). To reveal ecological mechanisms that affect bacterioplankton along the regime shift, Illumina MiSeq sequencing of the 16S rRNA gene combined with a novel network clustering tool (Manta) were used to identify patterns of bacterioplankton community composition across the regime shift in Taihu Lake, China. Marked divergence in the composition and ecological assembly processes of bacterioplankton community was observed under the regime shift. The alpha diversity of the bacterioplankton community consistently and continuously decreased with the regime shift from MDR to PDR, while the beta diversity presents differently. Moreover, as the regime shifted from MDR to PDR, the contribution of deterministic processes (such as environmental selection) to the assembly of bacterioplankton community initially decreased and then increased again as regime shift from MDR to PDR, most likely as a consequence of differences in nutrient concentration. The topological properties, including modularity, transitivity and network diameter, of the bacterioplankton co-occurrence networks changed along the regime shift, and the co-occurrences among species changed in structure and were significantly shaped by the environmental variables along the regime transition from MDR to PDR. The divergent environmental state of the regimes with diverse nutritional status may be the most important factor that contributes to the dissimilarity of bacterioplankton community composition along the regime shift.
在某些营养浓度下，浅水湖泊通常具有两种截然不同的生态系统特征，具有不同的生物多样性和生物地球化学循环模式：大型植物主导的生态系统（MDR）和浮游植物主导的生态系统（PDR）。为了揭示影响沿生态系统转变的细菌浮游生物的生态机制，我们使用 Illumina MiSeq 测序 16S rRNA 基因结合新型网络聚类工具（Manta），来识别中国太湖沿生态系统转变的细菌浮游生物群落组成模式。在生态系统转变过程中，观察到细菌浮游生物群落组成和生态组装过程明显分歧。随着从 MDR 向 PDR 的转变，细菌浮游生物群落的 alpha 多样性持续且连续下降，而 beta 多样性则呈现不同的情况。此外，随着从 MDR 向 PDR 的转变，细菌浮游生物群落组装的确定性过程（如环境选择）的贡献最初减少，然后随着从 MDR 向 PDR 的转变再次增加，这很可能是由于营养浓度的差异所致。随着从 MDR 向 PDR 的转变，细菌浮游生物共生网络的拓扑性质（包括模块性、传递性和网络直径）发生变化，物种之间的共生关系在结构上发生变化，并受到从 MDR 向 PDR 转变过程中环境变量的显著影响。不同营养状态的生态系统的不同环境状态可能是导致沿生态系统转变的细菌浮游生物群落组成差异的最重要因素。
