• 关键词：温度  淡水湖泊  水生植物  硫酸盐还原  铁还原

• 基金项目：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）

• 陈默
• 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

• 张雅庆
• 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

• 李家轩
• 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

• 焦一滢
• 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

• 赵丽娅
• 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

• 许峰
• 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

• 宋娜
• 1. 中国科学院南京地理与湖泊研究所, 南京 210008;2. 湖泊与环境国家重点实验室, 南京 210008

• 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.

• Abstract：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.

• Key words：temperature  freshwater lakes  macrophytes  sulfate reduction  iron reduction

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