Key Laboratory of Aquatic Botany and Watershed Ecology Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, PR China; Center of the Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Wuhan 430074, PR China.
Leibniz-Institude of Freshwater Ecology and Inland Fisheries (IGB), 16775, Neuglobsow, Germany; University of Potsdam, Institute of Biochemistry and Biology, Maulbeerallee 2, 14469, Potsdam, Germany.
Water Res. 2021 Feb 15;190:116751. doi: 10.1016/j.watres.2020.116751. Epub 2020 Dec 15.
Deciphering responses of rare versus abundant bacterioplankton to environmental change, crucial for understanding and mitigating of cyanobacterial blooms, is an important but poorly investigated subject. Using MiSeq sequencing, we investigated the taxonomic and phylogenetic diversity of rare and abundant bacterioplankton in eutrophic Lake Nanhu before and after dredging. We estimated environmental breadths and phylogenetic signals of ecological preferences of rare and abundant bacterioplankton, and investigated community function and bacterioplankton assembly processes. Both taxonomic and phylogenic distances of rare and abundant bacterioplankton communities were significantly positively correlated with the dissimilarity of environmental factors. Threshold indicator taxa analysis and Blomberg's K statistic indicated that rare taxa held broader environmental thresholds and stronger phylogenetic signals for ecological traits than abundant taxa. Environmental adaptations of both rare and abundant taxa exhibited distinct changes after dredging. Higher functional redundancy occurred in the abundant compared to the rare bacterioplankton, with functions of rare bacterioplankton decreasing and for the abundant ones increasing after dredging. The null model revealed that dispersal limitation belonging to stochastic processes determined the abundant bacterioplankton community assembly, whereas variable selection belonging to deterministic processes drove the rare one. Rare bacterioplankton was more environmentally constrained than the abundant one. Dissolved oxygen was the decisive factor in determining the balance between stochasticity and determinism in both rare and abundant bacterioplankton. Our study extends our knowledge of environmental adaptation of rare versus abundant bacterioplankton to massive disturbing measures, i.e. dredging, and allows to estimate dredging performance for mitigating cyanobacterial blooms from a molecular ecology viewpoint.
解析稀有与丰富浮游细菌对环境变化的响应，对于理解和减轻蓝藻水华至关重要，但这是一个研究不足的重要课题。本研究使用 MiSeq 测序，在疏浚前后调查了富营养化的南湖中稀有和丰富浮游细菌的分类和系统发育多样性。我们估计了稀有和丰富浮游细菌的环境宽度和生态偏好的系统发育信号，并研究了群落功能和浮游细菌组装过程。稀有和丰富浮游细菌群落的分类和系统发育距离与环境因子的差异呈显著正相关。阈值指示种分析和 Blomberg's K 统计表明，稀有分类群的生态特征的环境阈值较宽，系统发育信号较强，而丰富分类群则相反。疏浚后，稀有和丰富浮游细菌的环境适应都发生了明显的变化。与稀有浮游细菌相比，丰富浮游细菌的功能冗余度更高，疏浚后稀有浮游细菌的功能减少，而丰富浮游细菌的功能增加。零模型表明，属于随机过程的扩散限制决定了丰富浮游细菌群落的组装，而属于确定性过程的可变选择则驱动了稀有浮游细菌的组装。稀有浮游细菌比丰富浮游细菌受环境的限制更大。溶解氧是决定稀有和丰富浮游细菌中随机性和确定性之间平衡的决定性因素。本研究扩展了我们对稀有与丰富浮游细菌在大规模干扰措施（即疏浚）下的环境适应的认识，并从分子生态学的角度评估了疏浚对减轻蓝藻水华的效果。
