| 强降雨对平原河网区入湖河道氮、磷影响 |
| 摘要点击 2274 全文点击 948 投稿时间：2020-03-17 修订日期：2020-05-20 |
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| 中文关键词 暴雨 平原河网 湖泊 氮、磷 面源污染 |
| 英文关键词 heavy rain river-net plain lake nitrogen and phosphorus non-point pollution |
| 作者 | 单位 | E-mail | | 连心桥 | 安徽师范大学生态与环境学院, 芜湖 241003
中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室, 太湖湖泊生态系统研究站, 南京 210008 | lianxinqiao28@163.com | | 朱广伟 | 中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室, 太湖湖泊生态系统研究站, 南京 210008 | | | 杨文斌 | 安徽师范大学生态与环境学院, 芜湖 241003 | ywb1968@mail.ahnu.edu.cn | | 朱梦圆 | 中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室, 太湖湖泊生态系统研究站, 南京 210008 | | | 许海 | 中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室, 太湖湖泊生态系统研究站, 南京 210008 | |
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| 中文摘要 |
| 为定量揭示强降雨对平原河网河道氮、磷污染的影响，本文以太湖西岸大浦河和殷村港为例，基于两周年逐日高频人工监测和降雨量自动监测数据集，以及台风"利奇马"过程中的加密监测，分析了强降雨过程中河道各形态氮、磷浓度的变化特征及其环境效应.结果发现，强降雨两年内共观察到16次（19 d），且50%发生在夏季；此外，强降水占年内总降水量的比重高达41.33%.强降雨发生之后，两条河道水体中各形态氮、磷浓度在强降雨之后有所增加，其中颗粒态磷的响应最快，一般在强降雨当天就出现峰值；而总氮峰值的出现存在2~5 d的延迟；强降雨引发的河道营养盐浓度增高持续时间短，通常1~2 d，甚至低于雨前浓度.流域面积大和河道流程长的大浦河水体氮、磷浓度对强降雨过程的响应速度较殷村港慢.河道各形态氮、磷浓度对强降雨过程的响应特征还受河道两岸局地土地利用状况的影响，农业面源污染的河段比城镇污染的河段对营养盐的拦截、净化和缓冲能力弱，因此农业面源污染的河段对强降雨的响应强于城镇污染的河段；农业面源影响河段氮的增加量以颗粒态氮为主，城市面源影响河段氮的增加量以溶解态氮为主，而磷的增加全程均为颗粒态磷为主.平原河网地区强降雨带来的河道水体氮、磷浓度波动小，各形态氮、磷响应过程受局地环境背景影响大，水质总体趋于稳定.然而，由于强降雨带来的河道入湖水量占比大，因此入湖负荷也处于很高水平，加之强降雨的发生偶然性大，强降雨对平原河网地区河道入湖氮、磷负荷的突发影响很大，需要重点关注. |
| 英文摘要 |
| To understand the quantitative effect of heavy rain on nitrogen and phosphorus pollution in river-net plain, daily observations of nutrient concentrations in two rivers, flowing into Lake Taihu, were conducted from 1st September, 2017 to 31st August, 2019. The daily rainfall was recorded by auto-recording meteorological stations located on the two rivers and the Taihu Laboratory for Lake Ecosystem Research. Intensive sampling in different sections of the two rivers during Super Typhoon Lekima was also conducted in August 2019. Using these datasets, the influence of heavy rainfall on various forms of nitrogen and phosphorus concentrations in the rivers, and its environmental effects, were analyzed. The results showed that 16 heavy rainfall events (19 d) were observed in two years, 50% of which occurred in the summer season. In addition, heavy rainfall accounted for as much as 41.33% of the total rainfall over the entire year. After the period of heavy rainfall, the concentrations of various forms of nitrogen and phosphorus increased, and the particulate P generally exhibited the fastest response, usually peaking on the day of heavy rainfall. In contrast, the peaks of N were delayed for 2-5 days with the occurrence of heavy rain. In general, the duration of the increase in the concentration of nutrients in the study river caused by heavy rainfall was short (usually 1-2 days), and sometimes was lower than the concentration before the rains. The Dapu River exhibited a slower response to heavy rains than the Yincun River because it has a larger and longer catchment area than the Dapu River. In addition, the effect of heavy rain on N and P concentrations was also strongly influenced by the land-use situation around the river basin. The increase of nitrogen in the reach, affected by agricultural non-point sources, was dominated by granular nitrogen, and the increase of nitrogen in the reach affected by urban non-point sources was dominated by dissolved nitrogen. The increase of phosphorus was dominated by granular phosphorus in the entire process. The conclusions of this study are as follows:In the plain river network area, the fluctuations of nitrogen and phosphorus concentrations in the river water body caused by heavy rainfall are small, and the response of various forms of nitrogen and phosphorus are significantly affected by the local environmental background. Therefore, the water quality generally exhibited limited variation. Due to the large proportion of water entering the lake during heavy rainfall events, a high level of the nutrient loading was also observed, and the occurrence of heavy rainfall was occasional. The short-term effect of heavy rainfall on the nitrogen and phosphorus loading entering the lake in the river channel in the plain river network area is therefore, also significant, and requires further investigation. |
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