| 南水北调东线枢纽湖泊表层水体甲烷释放特征及潜在影响因素 |
| 摘要点击 1595 全文点击 561 投稿时间：2021-07-06 修订日期：2021-09-18 |
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| 中文关键词 骆马湖 甲烷 平行因子分析(PARAFAC) 溶解性有机质(DOM) 影响因素 |
| 英文关键词 Lake Luoma methane parallel factor analysis (PARAFAC) dissolved organic matter (DOM) influence factor |
| 作者 | 单位 | E-mail | | 朱俊羽 | 中国矿业大学资源与地球科学学院, 徐州 221116
中国科学院南京地理与湖泊研究所, 湖泊与环境国家重点实验室, 南京 210008 | zhujunyu6@126.com | | 彭凯 | 中国科学院南京地理与湖泊研究所, 湖泊与环境国家重点实验室, 南京 210008
中国科学院大学, 北京 100049 | | | 李宇阳 | 中国科学院南京地理与湖泊研究所, 湖泊与环境国家重点实验室, 南京 210008 | | | 俞晓琴 | 中国科学院南京地理与湖泊研究所, 湖泊与环境国家重点实验室, 南京 210008 | | | 陈慧敏 | 中国科学院南京地理与湖泊研究所, 湖泊与环境国家重点实验室, 南京 210008 | | | 周蕾 | 中国科学院南京地理与湖泊研究所, 湖泊与环境国家重点实验室, 南京 210008
中国科学院大学, 北京 100049 | | | 周永强 | 中国科学院南京地理与湖泊研究所, 湖泊与环境国家重点实验室, 南京 210008
中国科学院大学, 北京 100049 | | | 丁艳青 | 中国矿业大学资源与地球科学学院, 徐州 221116 | yqding7@163.com |
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| 中文摘要 |
| 湖泊是天然有机质生物地球化学循环和甲烷（CH4）排放的重要场所.观测南水北调东线枢纽湖泊骆马湖表层水体CH4溶存浓度和通量特征，并分析影响CH4释放的潜在因素.结果表明，骆马湖是CH4释放的热点区域，表层水CH4溶存浓度均值为（0.12±0.09）μmol·L-1，通量均值为（21.0±18.5）mmol·（m2·d）-1，总体表现为：丰水期>枯水期>平水期（P<0.05），空间上呈现西北高、东南低的趋势，年内CH4通量变化受水温和水文条件的协调影响；外源有机质输入（DOC和CDOM）为骆马湖CH4的产生提供了碳源，平行因子分析法得到水体4种荧光组分，类腐殖质C1与C3、类色氨酸C2和类酪氨酸C4，其中陆源类腐殖质的输入和累积显著促进了CH4的生产释放（P<0.01），同时，叶绿素a与CH4通量无相关性，意味着藻类降解的有机质并不是影响CH4释放的直接因素；骆马湖受人类活动影响深刻，北部入湖区氮、磷等营养负荷的输入不但提高了水体的生产力，加剧湖泊富营养化，还对水体CH4的产生和释放有调控作用.研究结果显示环境因子、DOM组成来源和营养水平等均是影响骆马湖水体CH4释放的重要因素，还需要进行长期连续观测以便全面评估各类因子对CH4释放的影响，进而可以采取相应措施有效减少CH4等温室气体的排放. |
| 英文摘要 |
| Lakes play an important role in the biogeochemical cycling of dissolved organic matter (DOM) and the emission of methane (CH4). We investigated the concentration and effluxes of CH4 and then analyzed the corresponding driving factors in Lake Luoma, a key lake along the South-to-North Water Transfer Project. Our results indicated that Lake Luoma was a hotspot of CH4 emissions with an annual mean concentration and efflux of (0.12±0.09) μmol·L-1 and (21.0±18.5) mmol·(m2·d)-1, respectively. We found higher mean CH4 levels in the wet season than those in the dry season and further higher levels than those in the wet-to-dry transition season. Spatially, the CH4 efflux was higher in the northwest inflowing regions and lower in the southeast outflow regions. The variability in annual CH4 efflux was affected by a combination of water temperature and hydrological conditions. Terrestrial input of dissolved organic carbon (DOC) and chromophoric DOM (CDOM) had fueled the production of CH4 by providing necessary carbon substrates, and four PARAFAC DOM components were identified including a microbial humic-like C1, a tryptophan-like C2, a terrestrial humic-like C3, and a tyrosine-like C4. The CH4 efflux from the lake was significantly promoted by the input and accumulation of terrestrial humic-like components, and Chl-a had no correlation with CH4 efflux, suggesting that algal degradation was not directly fueling the emission of CH4. Lake Luoma had been significantly disturbed by human activities, and terrestrial input of nutrient loading (TN and TP) into the lake not only improved the productivity and trophic level of the water body but also enhanced the production and release of CH4 from the surface water. We concluded that the CH4 emissions in Lake Luoma can be influenced by the combination of environmental factors, CDOM composition, and nutrient level. Long-term observation is needed for better evaluation of the driving factors in fueling the emission of CH4 so as to effectively reduce the emissions of CH4 and other greenhouse gases by taking corresponding countermeasures. |
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