沉水植被对河流温室气体释放减缓作用研究

Study on the mitigation effect of submerged vegetation on greenhouse gases emission from rivers

为揭示沉水植物生态修复在减缓河流温室气体释放方面的作用,在浙江省嘉善县选择盛家湾(有沉水植物)和东龙港(无沉水植物)2条河流,利用扩散模型法对其水体CO_(2)、CH_(4)、N_(2)O释放通量进行24h连续监测,并进行对比分析。结果表明:2条河流除盛家湾水体在16:00表现为CO_(2)吸收外,其余监测时间内3种气体均呈过饱和状态,表现为向大气释放温室气体,24 h内比较,有沉水植物的盛家湾可减少89%的温室气体释放。将气体释放通量与环境因子进行相关性分析发现,盛家湾水体CO_(2)释放通量与水温、pH、溶解氧浓度呈显著负相关,与氧化还原电位呈显著正相关,N_(2)O释放通量与水温、pH、溶解氧浓度呈显著正相关,与氧化还原电位呈显著负相关;东龙港水体CO_(2)释放通量与水温呈显著正相关,CH_(4)释放通量与水温、溶解氧浓度呈显著正相关,N_(2)O释放通量与水温呈显著正相关。

In order to reveal the role of ecological restoration of submerged plants in slowing down the release of greenhouse gases(GHGs)from rivers,the two rivers of Shengjiawan(with submerged plants growing)and Donglonggang(without submerged plants growing)were selected in Jiashan County,Zhejiang Province,and the fluxes of CO_(2),CH_(4) and N_(2)O were continuously monitored for 24 hours by the diffusion models.The results showed that except for the CO_(2) absorption occurrence in Shengjiawan at 16:00,the three gases were supersaturated during the rest of the monitoring time,showing the release of GHGs to the atmosphere.In comparison,within 24 hours,the release of GHGs from Shengjiawan with submerged plants could be reduced by 89%.Based on the correlation analysis between gas release flux and environmental factors,it was found that in Shengjiawan,CO_(2) emission flux was significantly negatively correlated with water temperature,pH and dissolved oxygen concentration,and positively correlated with redox potential.N_(2)O emission flux was positively correlated with water temperature,pH and dissolved oxygen concentration,and negatively correlated with redox potential.In Donglonggang,there was a significant positive correlation between CO_(2) release flux and water temperature,a significant positive correlation between CH_(4) release flux and water temperature and dissolved oxygen concentration,and a significant positive correlation between N_(2)O emission flux and water temperature.