Huang Jianrong, Yang Jian, Jiang Hongchen, Wu Geng, Liu Wen, Wang Beichen, Xiao Haiyi, Han Jibin
State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China.
State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Urumqi, China.
Front Microbiol. 2020 Aug 7;11:1772. doi: 10.3389/fmicb.2020.01772. eCollection 2020.
Uncovering microbial response to salinization or desalinization is of great importance to understanding of the influence of global climate change on lacustrine microbial ecology. In this study, to simulate salinization and desalinization, sediments from Erhai Lake (salinity 0.3-0.8 g/L) and Chaka Lake (salinity 299.3-350.7 g/L) on the Qinghai-Tibetan Plateau were transplanted into different lakes with a range of salinity of 0.3-299.3 g/L, followed by incubation for 50 days and subsequent geochemical and microbial analyses. Desalinization was faster than salinization in the transplanted sediments. The salinity of the transplanted sediment increased and decreased in the salinization and desalinization simulation experiments, respectively. The TOC contents of the transplanted sediments were lower than that of their undisturbed counterparts in the salinization experiments, whereas they had a strong negative linear relationship with salinity in the desalinization experiments. Microbial diversity decreased in response to salinization and desalinization, and microbial community dissimilarity significantly ( < 0.01) increased with salinity differences between the transplanted sediments and their undisturbed counterparts. Microbial groups belonging to and became abundant in salinization whereas and became dominant in desalinization. Among the predicted microbial functions, hydrogenotrophic methanogenesis, methanogenesis through CO reduction with H, nitrate/nitrogen respiration, and nitrification increased in salinization; in desalinization, enhancement was observed for respiration of sulfur compounds, sulfate respiration, sulfur respiration, thiosulfate respiration, hydrocarbon degradation, chemoheterotrophy, and fermentation, whereas depressing was found for aerobic ammonia oxidation, nitrate/nitrogen respiration, nitrification, nitrite respiration, manganese oxidation, aerobic chemoheterotrophy, and phototrophy. Such microbial variations could be explained by changes of transplantation, salinity, and covarying variables. In summary, salinization and desalinization had profound influence on the geochemistry, microbial community, and function in lakes.
揭示微生物对盐化或脱盐的响应对于理解全球气候变化对湖泊微生物生态的影响至关重要。在本研究中，为了模拟盐化和脱盐过程，将青藏高原洱海（盐度0.3 - 0.8 g/L）和茶卡盐湖（盐度299.3 - 350.7 g/L）的沉积物移植到盐度范围为0.3 - 299.3 g/L的不同湖泊中，随后进行50天的培养，并进行后续的地球化学和微生物分析。移植沉积物中的脱盐速度比盐化速度快。在盐化和脱盐模拟实验中，移植沉积物的盐度分别升高和降低。在盐化实验中，移植沉积物的总有机碳（TOC）含量低于未扰动的对应沉积物，而在脱盐实验中，它们与盐度呈强烈的负线性关系。微生物多样性随着盐化和脱盐而降低，并且移植沉积物与其未扰动对应物之间的微生物群落差异随着盐度差异显著（< 0.01）增加。属于 和 的微生物类群在盐化过程中变得丰富，而在脱盐过程中 和 成为优势类群。在预测的微生物功能中，氢营养型甲烷生成、通过H还原CO的甲烷生成、硝酸盐/氮呼吸和硝化作用在盐化过程中增加；在脱盐过程中，观察到硫化合物呼吸、硫酸盐呼吸、硫呼吸、硫代硫酸盐呼吸、烃降解、化学异养和发酵增强，而好氧氨氧化、硝酸盐/氮呼吸、硝化作用、亚硝酸盐呼吸、锰氧化、好氧化学异养和光合作用受到抑制。这种微生物变化可以通过移植、盐度和协变变量的变化来解释。总之，盐化和脱盐对湖泊的地球化学、微生物群落和功能有深远影响。
