摘要
识别和量化海湾水体硝态氮污染,对管理海湾水体环境至关重要.东山湾是福建省东南沿海重要的半封闭海湾,湾头漳江河口和湾口分别存在红树林和珊瑚礁生态系统,同时也伴随着海水养殖等人类活动影响.本研究通过测定海湾表层水体理化参数、稳定同位素(δ15N-NO3-、δ18O-NO3-和δ15N-NH4+),结合Mix-SIAR同位素混合模型等统计方法,定量化分析漳州东山湾表层水体硝态氮污染.结果表明:东山湾表层水体叶绿素a和溶解无机氮浓度呈现较为明显的梯度变化,表现为由漳江河口向东山湾湾口方向逐渐下降,叶绿素 a、NH4+、NO3-和 NO2-浓度的最大值分别为 45.2 μg·L-1、52.67 μmol·L-1、379.2 μmol·L-1 和 3.93μmol·L-1;表层水体NH4+和NO3-的氮、氧同位素值则表现为明显的空间异质性.MixSIAR模型结果显示,东山湾表层水体潜在氮源主要来源于漳江河口的淡水输入、养殖废水以及地下水等,其中漳江河口淡水输入的贡献最大,占25.2％,养殖废水、地下水以及城市污水分别占24.6％、19.0％和15.1％.可见,漳江河口淡水输入是东山湾表层水体硝酸盐最主要的来源.
Abstract
Identifying and quantifying water nitrate pollution is crucial for managing aquatic environment of a bay.Dongshan Bay,a significant semi-enclosed bay in the southeastern coastal area of Fujian Province,features man-grove and coral reef ecosystems at its estuary and bay mouth,respectively.Dongshan Bay is impacted by human ac-tivities such as mariculture.We quantified and analyzed nitrate pollution status in the surface waters of Dongshan Bay by measuring physicochemical parameters,stable isotopes(δ15N-NO3-,δ18O-NO3-and δ15N-NH4+)of the surface waters,and using statistical methods including the MixSIAR isotope mixing model.The results showed that the concentrations of chlorophyll a and dissolved inorganic nitrogen in the surface waters exhibited a noticeable gra-dient change,decreasing from the estuary of the Zhangjiang River to the mouth of Dongshan Bay.The maximum concentrations of chlorophyll a,NH4+,NO3-and NO2-were 45.2 µg·L-1,52.67 μmol·L-1,379.2 μmnol·L-1 and 3.93 μmol·L-1,respectively.The nitrogen and oxygen isotope values of NH4+and NO3-in the surface waters showed significant spatial variations.According to the MixSIAR model results,nitrogen sources in the surface waters of Dongshan Bay were mainly freshwater inputs of the Zhangjiang River estuary,aquaculture wastewater,and groundwater.The freshwater input from the Zhangjiang River estuary contributed the most(25.2％ ),while aquacul-ture wastewater,groundwater and urban sewage accounted for 24.6％ ,19.0％ ,and 15.1％ ,respectively.It is evi-dent that freshwater input from the Zhangjiang River estuary is the primary source of nitrate in the surface waters of Dongshan Bay.
基金项目
自然资源部第三海洋研究所基本科研业务费专项资金(海三科2023013)
自然资源部第三海洋研究所基本科研业务费专项资金(海三科2019017)
维普
万方数据