Effects of drought-rewetting processes and salinity variations on dissolved organic matter (DOM) transformation and bacterial communities in lacustrine sediments

作者：Zhu, Xiang; Xie, Lei; Ma, Yushen; Wang, Longmian^*; Pang, Qingqing; Peng, Fuquan; Xu, Zhipeng; Guo, Feihong; Ni, Lixiao; Wang, Ling

来源：JOURNAL OF SOILS AND SEDIMENTS, 2023, 23(11): 4055-4068.

DOI：10.1007/s11368-023-03611-x

• Drought rewetting process
• Salinity fluctuation
• Dissolved organic matter
• Fluorescent components
• Bacterial communities

PurposeClimate change and anthropogenic activities cause salinity fluctuations and frequent drought-rewetting processes in lacustrine littoral zones. However, the joint effects of these processes on the quality and quantity of dissolved organic matter (DOM) in pore water and bacterial communities in sediments are not well understood. Therefore, an experiment was conducted to attempt to fill the above gaps.Materials and methodsAn experiment with three salinities (1200, 3600, and 6000 mg L-1) and the drought-rewetting process was conducted. DOM characteristics were monitored by a UV-Vis spectrometer and a fluorescence spectrophotometer; bacterial communities were analyzed by 16S rRNA.Results and discussionHigher salinity (6000 mg L-1) and the drought-rewetting process retained more humified, more aromatic, and less bioavailable DOM and maintained lower DOM concentrations in pore water. Before the drought-rewetting process, Hydrogenophilaceae, Oxalobacteraceae, and Flavobacteriaceae participated in DOM transformation, while Hydrogenophilaceae, Desulfobacteraceae, Anaerolineaceae, Planococcaceae, and Clostridiaceae were associated with DOM components after this process. The drought-rewetting process, higher (6000 mg L-1) or lower (1200 mg L-1) salinity was not conducive to the stability of bacterial communities in sediments.ConclusionsSalinity fluctuations and drought-rewetting processes changed DOM characteristics in pore water and destabilized the bacterial communities. Therefore, it is necessary to take appropriate water recharge measures to avoid these processes.

• 单位
  河海大学