温度对湖泊沉积物中沉水植物残体厌氧分解的影响  

The effects of temperature differences on anaerobic degradation of submerged macrophytes litter in lake sediments

作　　者：陈默 张雅庆 李家轩 焦一滢 赵丽娅[1] 许峰[1] 宋娜[3,4] CHEN Mo;ZHANG Yaqing;LI Jiaxuan;JIAO Yiying;ZHAO Liya;XU Feng;SONG Na(Hubei Province Key Laboratory of Regional Development and Environment Response,School of Resources and Environmental Science,Hubei University,Wuhan 430062;Key Laboratory of Ecological Remediation of Lakes and Rivers and Algal Utilization of Hubei Province,School of Civil Engineering,Architecture and Environment,Hubei University of Technology,Wuhan 430068;Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,Nanjing 210008;State Key Laboratory of Lake Science and Environment,Nanjing 210008)

机构地区：[1]区域开发与环境响应湖北省重点实验室,湖北大学资源环境学院,武汉430062 [2]河湖生态修复及藻类利用湖北省重点实验室,湖北工业大学土木建筑与环境学院,武汉430068 [3]中国科学院南京地理与湖泊研究所,南京210008 [4]湖泊与环境国家重点实验室,南京210008

出　　处：《环境科学学报》2020年第8期3013-3019,共7页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金项目(No.41807452);湖北省自然科学基金项目(No.2018CFB311);湖泊与环境国家重点实验室开放基金资助项目(No.2018SKL011)。

摘　　要：淡水湖泊水生植物残体的腐烂分解过程为沉积物中的异养微生物提供了重要的碳源,但是目前关于温度对沉水植物残体有机质分解的影响研究还不够深入.本研究通过室内微宇宙模拟实验,研究了4℃和25℃时马来眼子菜残体在沉积物中厌氧分解特征及其主要的微生物代谢途径.结果表明,温度对马来眼子菜残体的分解影响显著,25℃实验组沉积物中总有机碳(TOC)和纤维素去除率显著高于4℃实验组.25℃实验组沉积物初始腐殖质占TOC比例为18.23%±1.47%,90 d后达到约46%,这说明微生物对马来眼子菜残体的分解促进了沉积物腐质化.此外,温度升高促进了纤维素降解细菌(如拟杆菌门,Bacteroidetes)的生长繁殖,且硫酸盐还原细菌(如GOUTA19、脱硫球菌属(Desulfocuccus)、LCP-6、HB118)和铁还原细菌(如地杆菌属,Geobacter)是沉积物中主要的优势菌种.在25℃条件下,微生物硫酸盐还原、铁还原和产甲烷作用占马来眼子菜残体厌氧代谢的比例分别达到37.3%、27.8%和10.3%.综上所述,本研究表明温度升高促进了沉积物中马来眼子菜残体的厌氧分解,且微生物硫酸盐还原、铁还原和产甲烷过程在其厌氧分解过程中发挥了重要作用.Anaerobic degradation of macrophytes litter in freshwater lakes provides important carbon source for heterotrophs in the sediments, however, the effects of temperature differences on decomposition of organic matter derived from macrophytes litters in sediments have not been well studied. In this study, microcosm experiments were conducted to study the characteristics of decomposition of Potamogeton malaianus(PM) litter and the main anaerobic microbial metabolic pathways for PM litter in sediments at 4℃and 25 ℃, respectively. Results indicated that temperature significantly influenced the degradation of PM litters, and the removal efficiencies of TOC and cellulose were significantly higher at 4 ℃ than 25 ℃. The initial ratio of humic matter to TOC in sediments was 18.23%±1.47% at 25 ℃, and the ration reached ca. 46% after 90 days, which indicated that microbial-mediated degradation of PM litters stimulated humification in the sediments. In addition, it was observed that increases in temperature promoted the growth of cellulolytic bacterium(like Bacteroidetes) in the sediments, and sulfate-reducing bacteria(like GOUTA19、Desulfocuccus、LCP-6 and HB118) and iron-reducing bacteria(like Geobacter) were the dominant bacteria. It was calculated that sulfate reduction, iron reduction and methanogenesis were responsible for 37.3%, 27.8% and 10.3% of total anaerobic respiration of PM litters in sediments. This study indicated that increases in temperature promoted anaerobic mineralization of PM litters in the sediments, and sulfate reduction, iron reduction and methanogenesis played an important role of the anaerobic mineralization of PM litter.

关 键 词：温度 淡水湖泊 水生植物 硫酸盐还原 铁还原 

分 类 号：X17[环境科学与工程—环境科学]