Zhu Kai, Jia Weitao, Mei Yu, Wu Shengjun, Huang Ping
Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, China.
Front Microbiol. 2023 May 12;14:1167353. doi: 10.3389/fmicb.2023.1167353. eCollection 2023.
Changes in the water regime are among the crucial factors controlling soil carbon dynamics. However, at the aggregate scale, the microbial mechanisms that regulate soil respiration under flooding and drying conditions are obscure. In this research, we investigated how the shift from flooding to drying changes the microbial respiration of soil aggregates by affecting microbial community composition and their co-occurrence patterns. Soils collected from a riparian zone of the Three Gorges Reservoir, China, were subjected to a wet-and-dry incubation experiment. Our data illustrated that the shift from flooding to drying substantially enhanced soil respiration for all sizes of aggregate fractions. Moreover, soil respiration declined with aggregate size in both flooding and drying treatments. The keystone taxa in bacterial networks were found to be , , , and during the flooding treatment, and , , , and during the drying treatment. For fungal networks, and were the keystone taxa in the flooding and drying treatments, respectively. Furthermore, the shift from flooding to drying enhanced the microbial respiration of soil aggregates by changing keystone taxa. Notably, fungal community composition and network properties dominated the changes in the microbial respiration of soil aggregates during the shift from flooding to drying. Thus, our study highlighted that the shift from flooding to drying changes keystone taxa, hence increasing aggregate-scale soil respiration.
水分状况的变化是控制土壤碳动态的关键因素之一。然而，在团聚体尺度上，洪水和干旱条件下调节土壤呼吸的微生物机制尚不清楚。在本研究中，我们研究了从淹水到干旱的转变如何通过影响微生物群落组成及其共生模式来改变土壤团聚体的微生物呼吸。从中国三峡水库河岸带采集的土壤进行了干湿培养实验。我们的数据表明，从淹水到干旱的转变显著增强了所有粒径团聚体组分的土壤呼吸。此外，在淹水和干旱处理中，土壤呼吸均随团聚体粒径减小而降低。在淹水处理期间，细菌网络中的关键类群为 、 、 、 ，在干旱处理期间为 、 、 、 。对于真菌网络， 和 分别是淹水和干旱处理中的关键类群。此外，从淹水到干旱的转变通过改变关键类群增强了土壤团聚体的微生物呼吸。值得注意的是，在从淹水到干旱的转变过程中，真菌群落组成和网络特性主导了土壤团聚体微生物呼吸的变化。因此，我们的研究强调，从淹水到干旱的转变改变了关键类群，从而增加了团聚体尺度的土壤呼吸。
