城市小型景观水体溶存甲烷(CH4)浓度特征及其影响因素 
- Characteristics of dissolved methane (CH4) concentrations and its influencing factors in small urban landscape waters
- 基金项目：国家自然科学基金项目(41907268)；浙江领雁研发攻关计划项目(No.2022C02019)；浙江农林大学校科研发展基金项目(2018FR005，2018FR006，2018FR061)
- 刘富平
- 浙江农林大学省部共建亚热带森林培育国家重点实验室
- 陈学兵
- 浙江农林大学省部共建亚热带森林培育国家重点实验室;浙江农林大学环境与资源学院、碳中和学院;浙江农林大学环境与资源学院、碳中和学院
- 田琳琳
- 浙江农林大学省部共建亚热带森林培育国家重点实验室
- 李彦
- 浙江农林大学省部共建亚热带森林培育国家重点实验室
- 蔡延江
- 浙江农林大学省部共建亚热带森林培育国家重点实验室;浙江农林大学环境与资源学院、碳中和学院;浙江农林大学环境与资源学院、碳中和学院
- 摘要：城市小型景观水体极易受人类活动的影响,易成为周边碳氮磷污染物的汇集地,是潜在的甲烷(CH4)排放源,然而目前对城市小型景观水体溶存CH4浓度(cobs(CH4))的认知还相对不足。本文以城市小型景观水体为研究对象,于2020年10月至2021年9月采用水-气顶空平衡-气相色谱法监测水体cobs(CH4),并同步测定理化指标和叶绿素a浓度,以明确水体cobs(CH4)的时空差异特征及其主要驱动机制。结果表明：各季节在白天8:00~10:00间的采样观测值能较好地表征本研究城市小型景观水体cobs(CH4)和饱和度(R(CH4))的日均值。水体cobs(CH4)及其R(CH4)的年均值分别为44.54 mg.L?1和103988%,水体溶存CH4过度饱和,是大气中潜在的CH4排放源。水体cobs(CH4)和R(CH4)均有显著的时空分异特征,夏季水体较低的氮、磷和溶解性有机碳浓度的共同作用是导致夏季水体cobs(CH4)较低的主要原因。中部湖区水体环境特点(较低的氮和磷浓度以及较高的WT和pH)和藻类初级生产(较高的叶绿素a和溶解氧浓度)的综合作用是致使其cobs(CH4)和R(CH4)显著低于其上游和下游水体的关键原因。本研究可为城市景观水体的生态环境管理及温室气体减排提供一定的理论支撑。
- Abstract：Small waters in the urban landscape, which can be markedly influenced by human activities and are susceptible to receive carbon, nitrogen, and phosphorus pollutants from surrounding landscapes, are the potential sources of CH4 emissions. However, the knowledge on the dissolved CH4 concentrations [cobs(CH4)] of these small waters remains largely unknown. In this study, we continuously monitored the cobs(CH4) by using method of headspace equilibration-gas chromatography, as well as the physic-chemical indicators and chlorophyll-a concentrations of small waters in a campus from October 2020 to September 2021. The aim was to disclose the spatio-temporal differences in cobs(CH4) in these waters and to clarify the main controlling factors. The observation during 8:00~10:00 am could well represent the daily average values of cobs(CH4) and its saturation levels [R(CH4)] in the waters in this study. The annual mean cobs(CH4) and R(CH4) of the waters were 44.54 μg.L–1 and 103988%, respectively. The cobs(CH4) in the water were over-saturated, indicating that the waters were potential sources of CH4 emission. There were significantly spatio-temporal differences of cobs(CH4) and R(CH4) in the waters. The lower cobs(CH4) in summer was the combined effects of lower nitrogen, phosphorus and dissolved organic carbon concentrations in the waters. The lake in the central region had significantly lower cobs(CH4) and R(CH4) than those in its upstream and downstream waters. The spatial differentiation was mainly attributed to the combined effects of water environment characteristics (lower nitrogen and phosphorus concentrations, higher water temperature and pH) and the primary production of algae (higher concentrations of chlorophyll-a and dissolved oxygen) in the central lake area. The findings of this study can benefit the ecological management and the greenhouse gas emission mitigation of the water body in the urban landscape.
