Guo Jiaxun, Wang Xu, Cao Xiaofeng, Qi Weixiao, Peng Jianfeng, Liu Huijuan, Qu Jiuhui
Center for Water and Ecology, State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
Center for Water and Ecology, State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
Sci Total Environ. 2023 Dec 10;903:166036. doi: 10.1016/j.scitotenv.2023.166036. Epub 2023 Aug 6.
In lake environments, seasonal changes can cause exposure of the lake sediment, leading to soil formation. Although previous studies have explored how environmental changes influence microbial functioning in the water-level-fluctuating zone, few studies have investigated how wholescale habitat changes affect microbial composition, community stability and ecological functions in lake environments. To address this issue, our study investigated the effects of sediment-to-soil conversion on microbial composition, community stability and subsequent ecological functioning in Poyang Lake, China. Our results revealed that, during sediment-to-soil conversion, the number of total and unique operational taxonomic units (OTUs) decreased by 40 % and 55 %, respectively. Moreover, sediment-to-soil conversion decreased the microbial community connectivity and complexity while significantly increasing its stability, as evidenced by increased absolute values of negative/positive cohesion. In sediment and soil, the abundance of dominant bacteria, and bacterial diversity strongly affected microbial community stability, although this phenomenon was not true in water. Furthermore, the specific microbial phyla and genes involved in the nitrogen cycle changed significantly following sediment-to-soil conversion, with the major nitrogen cycling processes altering from denitrification and dissimilatory nitrate reduction to ammonium to nitrification and assimilatory nitrate reduction to ammonia. Moreover, a compensation mechanism was observed in the functional genes related to the nitrogen cycle, such that all the processes in the nitrogen cycle were maintained following sediment-to-soil conversion. The oxidation-reduction potential strongly affected network complexity, microbial stability, and nitrogen cycling in the sediment and soil. These results aid in the understanding of responses of microorganisms to climate change and extreme drought. Our findings have considerable implications for predicting the ecological consequences of habitat conversion and for ecosystem management.
在湖泊环境中，季节性变化会导致湖底沉积物暴露，从而形成土壤。尽管先前的研究已经探讨了环境变化如何影响水位波动带的微生物功能，但很少有研究调查整体生境变化如何影响湖泊环境中的微生物组成、群落稳定性和生态功能。为了解决这个问题，我们的研究调查了沉积物向土壤转化对中国鄱阳湖微生物组成、群落稳定性及后续生态功能的影响。我们的结果表明，在沉积物向土壤转化过程中，总操作分类单元（OTU）和独特OTU的数量分别减少了40%和55%。此外，沉积物向土壤的转化降低了微生物群落的连通性和复杂性，同时显著提高了其稳定性，负/正内聚绝对值的增加证明了这一点。在沉积物和土壤中，优势细菌的丰度和细菌多样性强烈影响微生物群落稳定性，尽管在水体中并非如此。此外，沉积物向土壤转化后，参与氮循环的特定微生物门类和基因发生了显著变化，主要的氮循环过程从反硝化作用和异化硝酸盐还原为铵转变为硝化作用和同化硝酸盐还原为氨。此外，在与氮循环相关的功能基因中观察到一种补偿机制，使得氮循环中的所有过程在沉积物向土壤转化后得以维持。氧化还原电位强烈影响沉积物和土壤中的网络复杂性、微生物稳定性和氮循环。这些结果有助于理解微生物对气候变化和极端干旱的响应。我们的研究结果对于预测生境转化的生态后果和生态系统管理具有重要意义。
