2016-2021年长江口海域营养盐时空变化特征及其影响因素研究  

Spatiotemporal Characteristics of Nutrients in the Yangtze River Estuary from 2016 to 2021 and Their Influencing

作　　者：何柄震 王艳[2] 王彪[3] 卢士强[3] 雷坤[2] 李立群 程全国[1] HE Bingzhen;WANG Yan;WANG Biao;LU Shiqiang;LEI Kun;Li Liqun;CHENG Quanguo(Key Laboratory of Eco-Restoration of Regional Contaminated Environment(MOE),Shenyang University,Shenyang 110044,China;Basin Research Center for Water Pollution Control,Chinese Research Academy of Environmental Sciences,Beijing 100012,China;Shanghai Academy of Environmental Sciences,Shanghai 200233,China)

机构地区：[1]沈阳大学,区域污染环境生态修复教育部重点实验室,辽宁 沈阳110044 [2]中国环境科学研究院流域水环境污染综合治理研究中心,北京100012 [3]上海市环境科学研究院,上海200233

出　　处：《环境科学研究》2024年第2期221-232,共12页Research of Environmental Sciences

基　　金：国家重点研发计划项目(No.2021YFC3101700)。

摘　　要：为研究长江口海域营养盐时空变化特征及其主要影响因素,本研究基于2016-2021年长江口生态环境监测数据、长江流域入海断面监测数据以及长江径流数据,根据长江口盐度(S)空间分布特点,将该海域分为口门区(S<5‰)、河口区(5‰<S<25‰)和海水区(S>25‰),从分区的角度探讨长江口海域溶解性无机氮(DIN)、磷酸盐(PO_(4)-P)、硅酸盐(SiO_(3)-Si)的浓度时空分布、营养盐结构及限制因子.结果表明:①时间上,2016-2021年DIN、PO_(4)-P浓度呈波动下降趋势,SiO_(3)-Si浓度则呈波动上升趋势.DIN浓度主要表现为春季>夏季>秋季,PO_(4)-P和SiO_(3)-Si浓度则均呈现秋季>夏季>春季的趋势.②空间上,DIN、SiO_(3)-Si浓度均呈由近岸向远海逐渐递减的趋势,均表现为口门区>河口区>海水区,而PO_(4)-P浓度则表现为河口区>口门区>海水区.这说明DIN、PO_(4)-P、SiO_(3)-Si浓度都受到长江冲淡水的影响.PO_(4)-P浓度高值区通常位于最大浊度带附近,悬浮颗粒物(TSM)浓度在一定程度上影响PO_(4)-P浓度的分布情况.浮游植物的生长繁殖是营养盐浓度变化的重要原因之一.③长江口海域营养盐结构具有分布不均衡的特点,N/P、Si/P均远大于16∶1,Si/N则均接近1,这说明磷为长江口海域浮游植物潜在限制因子.Chla浓度的相对高值区域大都处于磷限制,其值越高,N/P和Si/P则普遍越大,生物的吸收作用会使磷的限制程度加剧,说明浮游植物对长江口海域营养盐结构具有重要的影响.研究显示:长江口海域营养盐分布具有明显的规律性,长江冲淡水对营养盐的空间分布有着重要影响,浮游植物的吸收作用是营养盐及其结构的影响因素之一.According to the partition method,the water quality and ecological monitoring data of the Yangtze River Estuary from 2016 to 2021 were used to analyze the spatiotemporal characteristics of nutrients and its influencing factors.The study area was divided into entrance zone(S<5‰),estuary(5‰<S<25‰)and seawater zone(S>25‰).The results show that:(1)The concentrations of DIN and PO_(4)-P showed fluctuating downward trends,and SiO_(3)-Si showed fluctuating upward trends from 2016 to 2021.The DIN concentration of mainly showed a trend of spring>summer>autumn,while PO_(4)-P and SiO_(3)-Si were the opposite.(2)Affected by the freshwater of the Yangtze River,the concentrations of DIN and SiO_(3)-Si showed a trend of entrance zone>estuary>seawater zone,while the PO_(4)-P concentration was highest in the estuary.The area with high PO_(4)-P concentration was usually located near the maximum turbidity zone.The growth and reproduction of phytoplankton was one of the most important reasons for nutrients.(3)The distribution of nutrients in the Yangtze River Estuary was uneven,with N/P and Si/P much larger than 16∶1 and Si/N close to 1.Phosphorus was a potential limiting factor for phytoplankton.The relatively high value area of chlorophyll a was mainly limited by P,and N/P and Si/P were generally high.The absorption of organisms will exacerbate the degree of P limitation,suggesting that phytoplankton have an important impact on the nutrient structure.The research shows that the distribution of nutrients in the Yangtze River Estuary has obvious regularity,and the freshwater of the Yangtze River has an important influence on the spatial distribution of nutrients.The absorption of phytoplankton was one of the influence factors of nutrient structure.The research results can provide a basis for the improvement of the ecological environment of the Yangtze River Estuary.

关 键 词：长江口海域 营养盐 时空变化 影响因素 

分 类 号：X55[环境科学与工程—环境工程]