| 摘要: |
| 湿地是地球上十分重要的氮库，而且对大气氮沉降增加、气候变暖等全球变化响应非常敏感。目前关于湿地氧化亚氮（N2O）的研究还存在较大的区域不均衡性，湿地N2O排放对全球变化的响应也具有很大的不确定性。因此，本研究通过在鄱阳湖灰化薹草（Carex cinerascens Kukenth.）湿地开展N2O通量原位监测及全球变化模拟实验，以揭示鄱阳湖灰化薹草湿地N2O排放变化特征及其对施氮和增温的响应关系。结果表明，鄱阳湖灰化薹草湿地总体上是N2O弱源，平均N2O通量为(5.77±1.45) μg/(m2·h)。施氮对鄱阳湖灰化薹草湿地N2O通量有显著影响，相对于不施氮，施氮可显著提升2.7倍的N2O排放通量。增温及其与施氮的交互作用对N2O通量的影响不显著。鄱阳湖灰化薹草湿地N2O排放过程主要由湿地植物调节，而与空气温度、土壤温度、土壤水分等非生物因素无显著相关关系。研究结果有利于深入认识全球变化与湖泊湿地N2O排放的互馈作用，并为评估全球变化背景下湖泊湿地N2O收支平衡提供重要支撑；未来还需要加强多因子交互作用研究并开展长期连续监测，从而为阐明湿地氮循环对全球变化的响应机制和构建气候预测模型提供验证数据和理论依据。 |
| 关键词: 鄱阳湖湿地 温室气体 N2O 全球变化 氮沉降 气候变暖 |
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| 基金项目:江西省自然科学基金项目（20224BAB213035）、江西省重点研发计划项目（20223BBG74003）、九江市自然科学基金项目（S2022XCTD001）和中国科学院南京地理与湖泊研究所科技创新规划项目（NIGLAS2022TJ13，2021NIGLAS-CJH01）联合资助 |
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| Effects of nitrogen addition and warming on nitrous oxide emission during the autumn growing season of Carex cinerascens Kukenth. meadow in Lake Poyang |
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CHENG Junxiang,XU Ligang,FAN Longfeng,CHEN Xi,YOU Hailin
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Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences
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| Abstract: |
| Wetlands are extremely important nitrogen pool on Earth, and are highly sensitive to global changes such as increased atmospheric nitrogen deposition and climate warming. Previous studies on wetland nitrous oxide (N2O) had large regional imbalance. The responses of wetland N2O emissions to global changes remain unclear. In this study, we carried out in situ N2O flux monitoring, and implemented global change experiments in a Carex cinerascens Kukenth. meadow of Lake Poyang to characterize N2O emission and its response to nitrogen addition and warming. The results showed that the C. cinerascens wetland of Lake Poyang was generally a weak source of N2O, with an average N2O flux of (5.77±1.45) μg/(m2·h). Nitrogen addition significantly increased N2O flux by 2.7 times. There were no significant effects of warming and its interaction with nitrogen addition on N2O flux. N2O efflux was mainly regulated by wetland plants, while there was no significant correlation between N2O flux and abiotic factors such as air temperature, soil temperature and soil moisture. These results provided in-depth understanding of the feedbacks between global changes and N2O emissions from lake wetlands, and provided support for the assessment of N2O budget in lake wetlands under the background of global changes. In the future, it is necessary to strengthen the study of multi-factor interactions, and to carry out long-term continuous monitoring, and thus to provide validation data and theoretical basis for elucidating the response mechanism of wetland nitrogen cycle to global changes and developing climate prediction models. |
| Key words: Poyang Lake wetland greenhouse gases N2O global change nitrogen deposition climate warming |
