Joint International Research Laboratory of Global Change and Water Cycle, State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, 1 Xikang Road, Nanjing 210098, China.
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China.
FEMS Microbiol Ecol. 2022 May 23;98(6). doi: 10.1093/femsec/fiac051.
Unveiling the rules of bacterioplankton community assembly in anthropogenically disturbed lakes is a crucial issue in aquatic ecology. However, it is unclear how the ecological processes underlying the seasonally driven bacterioplankton community structure respond to varying degrees of lake eutrophication. We, therefore, collected water samples from three subtropical freshwater lakes with various trophic states (i.e. oligo-mesotrophic, mesotrophic, and eutrophic states) on a quarterly basis between 2017 and 2018. To innovatively increase our understanding of bacterioplankton community assembly along the trophic state gradient, the total bacterioplankton community dissimilarity was subdivided into balanced variation in abundances and abundance gradients. The results indicated that balanced-variation component rather than abundance-gradient component dominated the total temporal β-diversity of bacterioplankton communities across all trophic categories. Ecological stochasticity contributed more to the overall bacterioplankton community assembly in the oligo-mesotrophic and mesotrophic lakes than in the eutrophic lake. The reduced bacterioplankton network complexity at the eutrophic level was closely associated with the enhancement of environmental filtering, showing that bacterioplankton communities in eutrophic lakes are likely to be less stable and more vulnerable to water quality degradation. Together, this study offers essential clues for biodiversity conservation in subtropical lakes under future intensified eutrophication.
揭示人为干扰湖泊中细菌浮游生物群落组装的规律是水生生态学中的一个关键问题。然而，目前尚不清楚季节驱动的细菌浮游生物群落结构的生态过程如何响应不同程度的湖泊富营养化。因此，我们在 2017 年至 2018 年间，每季度从三个具有不同营养状态（即寡营养、中营养和富营养状态）的亚热带淡水湖中采集水样。为了创新地增加我们对沿营养状态梯度的细菌浮游生物群落组装的理解，将总细菌浮游生物群落的差异细分为丰度平衡变化和丰度梯度。结果表明，在所有营养类别中，平衡变化成分而不是丰度梯度成分主导了细菌浮游生物群落的总时间β多样性。生态随机性对寡营养和中营养湖泊中细菌浮游生物群落的整体组装贡献大于富营养湖泊。在富营养水平下，细菌浮游生物网络复杂性的降低与环境过滤的增强密切相关，表明富营养湖泊中的细菌浮游生物群落可能不太稳定，更容易受到水质恶化的影响。总的来说，这项研究为未来强化富营养化条件下亚热带湖泊的生物多样性保护提供了重要线索。
