摘要：Dissolved organic matter (DOM) in the ocean is one of the largest carbon pools on Earth. Microbial metabolism is an important process that shapes the marine DOM pool. Current studies on the interactions between microorganisms and DOM focus mainly on oxic environments. Few studies have addressed the molecular characteristics of DOM in microbial-mediated transformation under anoxic/hypoxic conditions. As a result of deteriorating water quality due to eutrophication and global warming, anoxia occurs frequently in coastal waters. In this study, we performed an experiment to investigate changes in microbial community responses and the molecular characteristics of DOM in microbial-mediated transformation under hypoxic conditions. We compared microbial-mediated DOM transformation at different dissolved oxygen levels (7, 5, and 2 mg L (-1)) and in different media (natural and artificial seawater with and without laminarin). We also investigated differences in DOM composition between groups using spectroscopic analysis and ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry. The results showed decreased microbial metabolic activity and delayed community succession at low oxygen (<= 2 mg L (-1)) in natural seawater supplemented with laminarin. The growth of strictly aerobic bacteria such as Pseudomonadaceae and Sphingomonadaceae was inhibited and the total organic carbon utilization rate was reduced by 36.9-6.7% from 4 to 32 days. Moreover, tyrosine-like and tryptophan-like components were preserved, while DOM humification and modified aromaticity index were significantly reduced under low oxygen conditions. This experiment provides justification for further study of the processes and mechanisms of improved labile DOM preservation in anoxic estuarine and coastal waters.

关键字：Anoxic; hypoxic; Microbial community structure; Dissolved organic matter; Chemical characteristics of molecule

ISSN号：1674-7313

卷、期、页：卷66期4：894-909

发表日期：2023-03-01

影响因子：0.000000

期刊分区（SCI为中科院分区）：二区

收录情况：SCI（科学引文索引印刷版）,EI（工程索引）,SCIE（科学引文索引网络版）

发表期刊名称：SCIENCE CHINA-EARTH SCIENCES

参与作者：肖仕聪,陈佳欣,沈渊,陈奇,王煜,蔡阮鸿,焦念志,郑强

通讯作者：李运运

第一作者：何晨,史权

论文类型：期刊论文

论文概要：肖仕聪,陈佳欣,沈渊,陈奇,王煜,李运运,何晨,蔡阮鸿,史权,焦念志,郑强，Molecular characterization of organic matter transformation mediated by microorganisms under anoxic/hypoxic conditions，SCIENCE CHINA-EARTH SCIENCES，2023，卷66期4：894-909

论文题目：Molecular characterization of organic matter transformation mediated by microorganisms under anoxic/hypoxic conditions