长兴仙山湖沉水植物降低湿地中温室气体排放

Submerged Aquatic Plants Can Decrease Greenhouse Gas Emissions from a Pond of Xianshan Lake, Changxing

摘要: 湿地是甲烷(CH₄)、二氧化碳(CO₂)、氧化亚氮(N₂O)等温室气体重要的排放源，对全球气候变暖产生重要的影响，如何降低湿地温室气体排放是一项重要的课题。本实验选择长兴仙山湖国家湿地公园周边的池塘作为研究地点，选取苦草(Vallisneria natans)、狐尾藻(Myriophyllum verticillatum L.)两种沉水植物，在池塘中建立6个正方形围隔(2 × 2 m)，设置3个密度梯度(50株/m2、100株/m2、150株/m2)分别种植苦藻(V. natans)、狐尾藻(M. verticillatum L.)。种植15天后，采用静态浮箱–气相色谱法测定各个围隔中的CH₄、CO₂、N₂O排放通量。结果表明，与对照组(围隔外无植物覆盖水面)相比，种植沉水植物围隔可使CH₄排放通量降低56.1%~91.9%，而将CO₂的排放源变成吸收汇，但对N₂O排放的影响差异不显著。所以，在池塘、湖泊、水库等湿地中种植沉水植物是降低湿地温室气体排放的有效策略。

Abstract: Wetland is an important emission source for methane (CH₄), carbon dioxide (CO₂), and nitrous oxide (N₂O), which is crucial to global climate change. Thus, how to decrease greenhouse gases emissions from wetland is an important problem to study. Enclosure experiments are carried out to study impacts of submerged aquatic plants on greenhouse gases emissions. We plant Vallisneria natans and Myriophyllum verticillatum L. in 6 mesocosms (2 × 2 m) with different densities, i.e., 50 plants/m2, 100 plants/m2, 150 plants/m2, in a pond of Xianshan National Wetland Park. CH₄, CO₂, and N₂O emission fluxes are measured in each mesocosm by the floating chambers combined with a gas chromatogram after 15 days of replanting the submerged aquatic plants. The results indicate that CH₄ emissions from the mesocosms with submerged aquatic plants decrease 56.1% - 91.9% compared with the control group (waters without plants), and CO₂ emissions shift an original CO₂ source into a sink, but N₂O emissions have no significant change. Therefore, it is an effective strategy to decrease greenhouse gases emissions by planting submerged aquatic plants in ponds, lakes or reservoirs.