Environment Research Institute, Shandong University, Qingdao, 266237, China.
State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China, Xi'an University of Technology, Xi'an, 710048, China.
Environ Sci Pollut Res Int. 2021 Sep;28(33):44973-44986. doi: 10.1007/s11356-021-13843-4. Epub 2021 Apr 15.
Whether natural wetlands serve as the source or sink of greenhouse gases (GHGs) remains uncertain. Wetlands in China are diverse in type and abundant in quantity and differ greatly in spatial distribution, environmental conditions, and GHG fluxes. However, few studies focused on the differences in GHG emissions from different types of natural wetlands. Here, we adopted strict data collection criteria to create comprehensive and detailed datasets of fluxes of carbon dioxide (CO), methane (CH), and nitrous oxide (NO) from the marsh, coastal, lake, and river wetlands in China, and relevant environmental variables. Our study synthesized 265 field observations on GHGs that lasted at least one year (covering both the growing season and non-growing season) from 109 studies, among which CO measurements using the opaque chamber method were not included for eliminating the influence of absence of photosynthesis on net CO accounting. We found that CH contributed the largest warming effect among the three types of GHGs, and coastal and river wetlands respectively acted as the mitigators and motivators of global warming among the four types of wetlands. Correlation and regression analyses suggested that geographic location, soil moisture and organic carbon, and contents of nitrogen, phosphorus, and dissolved oxygen jointly drove wetland GHG fluxes. The comprehensive global warming potential of Chinese natural wetlands was estimated as 427 Tg CO-equivalents year, which might result from increased wetland drainage, reclamation, and external nutrient inputs. This study highlights the incorporation of the full year-round GHG monitoring data without using opaque chambers to measure CO flux when extrapolating net GHG emissions and gives implications for natural wetland management and global warming mitigation strategies.
自然湿地是温室气体（GHGs）的源还是汇仍不确定。中国的湿地类型多样，数量丰富，在空间分布、环境条件和温室气体通量方面差异很大。然而，很少有研究关注不同类型的自然湿地温室气体排放的差异。在这里，我们采用严格的数据收集标准，为中国的沼泽、沿海、湖泊和河流湿地的二氧化碳（CO）、甲烷（CH）和氧化亚氮（NO）通量以及相关环境变量创建了全面而详细的数据集。我们的研究综合了 109 项研究中 265 个至少持续一年（包括生长季和非生长季）的温室气体观测结果，其中不包括使用不透明室方法测量的 CO，以消除光合作用缺失对净 CO 核算的影响。我们发现，在这三种温室气体中，CH 对变暖的贡献最大，而在四种湿地类型中，沿海和河流湿地分别是全球变暖的缓解者和促进者。相关和回归分析表明，地理位置、土壤湿度和有机碳以及氮、磷和溶解氧的含量共同驱动湿地温室气体通量。中国自然湿地的综合全球变暖潜势估计为 427Tg CO 当量年，这可能是由于湿地排水、开垦和外部养分输入增加所致。本研究强调了在推断净温室气体排放时纳入全年温室气体监测数据而不使用不透明室测量 CO 通量的重要性，并为自然湿地管理和全球变暖缓解策略提供了启示。
