大亚湾海域2019~2023年氮、磷营养盐的变化及富营养化评价

Changes in Nitrogen and Phosphorus Nutrients and Eutrophication Assessment in Daya Bay from 2019 to 2023

摘要: 笔者为了解大亚湾海域海水中氮(N)、磷(P)营养盐的时空分布情况及富营养化程度，基于2019~2023年间大亚湾海域海水采样监测数据进行分析。结果表明：1) 2019~2023年期间，大亚湾海域DIN和DIP的浓度在时间上呈现先增后降的趋势，DIN和DIP的浓度在2020年达到最大值，在2023年达到最小值。在空间上呈现从大亚湾湾顶至湾口逐渐降低的趋势，主要集中在大亚湾西北部的澳头海域的网箱养殖区；2) 大亚湾海域营养盐结构在2020~2022年内发生了变化，由相对磷限制变为相对氮限制；3) 陆源输入和海产养殖是大亚湾海域出现富营养化的主要影响因素，随着近年管控的加强，大亚湾海域整体上经历了由中度富营养转为轻度富营养，最终无富营养化的过程。

Abstract: To understand the spatio-temporal distribution and eutrophication level of nitrogen (N) and phosphorus (P) nutrients in the seawater of Daya Bay, the authors collected the seawater samples and analyzing data from 2019 to 2023. The results showed that: 1) From 2019 to 2023, the concentrations of in the seawater of DIN and DIP in Daya Bay exhibited a trend of increasing first and then decreasing over time. The concentrations of DIN and DIP reached their maximum values in 2020 and their minimum values in 2023. Spatially, they showed a gradual decrease from the bayhead to the bay mouth, mainly concentrated in the cage culture area of the Aotou sea area in the northwest of Daya Bay; 2) The nutrient structure in Daya Bay changed from being relatively phosphorus-limited to nitrogen-limited between 2020 and 2022; 3) Land-based inputs and marine aquaculture are the main factors contributing to eutrophication in Daya Bay. With the strengthening of control measures in recent years, Daya Bay has undergone a transition from moderate eutrophication to mild eutrophication, and ultimately to a state without eutrophication.