Microbial mechanisms for methane source-to-sink transition after wetland conversion to cropland
Microbial mechanisms for methane source-to-sink transition after wetland conversion to cropland
复制标题
湿地转化为农田后甲烷从源到汇转变的微生物机制
DOI：
10.1016/j.geoderma.2022.116229
复制
发表时间：
2023
期刊：
影响因子：
6.1
通讯作者：
Guo, Dufa
中科院分区：
文献类型：
--
作者：
Wang, Nannan;Zhu, Xinhao;Zuo, Yunjiang;Liu, Jianzhao;Yuan, Fenghui;Guo, Ziyu;Zhang, Lihua;Sun, Ying;Gong, Chao;Guo, Dufa
湿地转化为农田大大减少了甲烷（CH4）的排放，在许多情况下将源转化为汇；各种微生物过程如何促成这种从源到汇的转变仍然难以捉摸。本研究通过对三江平原原始湿地和23年耕地的净ch4通量、ch4生产潜力、ch4氧化潜力以及与甲烷生成和甲烷化相关的功能基因进行研究，解决了这一问题。研究证实，湿地转化为农田将44.93±10.17 g CH4·m−2·yr−1的CH4源转化为−0.056±0.051 g·CH4−2·yr−1的CH4小汇。ch4总相关基因、产甲烷基因和ch4生产标记基因- mcr所占比例分别显著减少24.14%、32.10%和97.89%。湿地栽培后，甲烷营养标志基因、pMMO的比例、smmo2和pmmo2的总和显著增加了48.74%和22.79%。栽培23年，四季对产甲烷和产甲烷基因均有抑制作用，春、夏对smmo、pMMO和mmo3个功能基因均有促进作用。ch4相关基因的比例在湿地和农田沿土层深度呈下降趋势，而在农田20 ~ 60 cm土层，epmmoand mmo2基因的比例略有增加。一项全球综合研究支持这一甲烷源-汇转变的微生物机制，表明湿地改田后甲烷源-汇转变具有强烈的产甲烷抑制和轻微的产甲烷增强作用。这一机制应纳入ch4模型，以预测土地利用变化下ch4的动态变化。
Wetland conversion to cropland substantially reduces methane (CH4) emission, turning a source into a sink on many occasions; how various microbial processes contribute to this source-to-sink transition remains elusive. We addressed this issue by examining the net CH4flux, CH4production potential, CH4oxidation potential, and functional genes associated with methanogenesis and methanotrophy in a pristine wetland and a 23-year cultivated cropland in the Sanjiang Plain, China. The study confirmed that wetland conversion to cropland turned a CH4source of 44.93 ± 10.17 g CH4·m−2·yr−1to a small CH4sink of −0.056 ± 0.051 g·CH4m−2·yr−1. The proportion of total CH4-related genes, methanogenesis genes, as well as the CH4production marker genes –mcrwere significantly decreased by 24.14 %, 32.10 %, and 97.89 %, respectively in cropland. The proportions of methanotrophic marker genes,pMMO,and the sum ofsMMOandpMMOwere significantly increased by 48.74 % and 22.79 % after wetland cultivation. The 23-year cultivation yielded suppressing impacts on methanogenesis andmcrgenes throughout the four seasons while stimulating effects on the functional genes ofsMMO,pMMO,andMMOin spring and summer. The proportions of CH4-related genes decreased along soil depth in wetland and cropland, whilepMMOandMMOslightly increased in the depth of 20–60 cm in cropland. A global synthesis supported this microbial mechanism for the CH4source-to-sink transition, indicating the strong methanogenesis suppression and slight methanotrophy enhancement in explaining the source-to-sink transition after wetland conversion to cropland. This mechanism should be incorporated into CH4models to predict CH4dynamics under land-use change.