El Niño影响下珠江口及其邻近海域营养盐时空变化及其生态效应  

The spatiotemporal variations of nutrients and its ecological response in the Pearl River Estuary and its adjacent sea areas under the influence of El Niño

作　　者：马玉 张伟杰 李锐祥 朱鹏利 牟健 刘长建 张金尚 苏锡宝 梁宇钊 曾芳 MA Yu;ZHANG Weijie;LI Ruixiang;ZHU Pengli;MU Jian;LIU Changjian;ZHANG Jinshang;SU Xibao;LIANG Yuzhao;ZENG Fang(South China Sea Marine Survey Center,Ministry of Natural Resources,Guangzhou 510300;Key Laboratory of Marine Environmental Survey Technology and Application,Ministry of Natural Resources,Guangzhou 510300)

机构地区：[1]自然资源部南海调查中心,广州510300 [2]自然资源部海洋环境探测技术与应用重点实验室,广州510300

出　　处：《环境科学学报》2023年第5期36-46,共11页Acta Scientiae Circumstantiae

基　　金：国家重点研发计划(No.2018YFB1802300);自然资源部南海局科技发展基金(No.202205)。

摘　　要：2019—2020年在珠江口开展了四季水体营养盐和环境因子的现状调查.结果发现,与常年(多年平均)不同,El Niño影响下华南地区及广东省前汛期降水量显著增大,春季珠江入海径流大于夏季,水体平均盐度为26.56,低于夏季(30.61),非汛期(秋、冬季)降水量和入海径流急剧减少,秋季平均盐度(32.39)最大.四季溶解无机氮(DIN)平均浓度排序为春季(0.38 mg·L^(-1))>夏季(0.18 mg·L^(-1))>冬季(0.16 mg·L^(-1))>秋季(0.08 mg·L^(-1)),磷酸盐(DIP)平均浓度排序为冬季(0.009 mg·L^(-1))>夏季(0.006 mg·L^(-1))>春季(0.004 mg·L^(-1))和秋季(0.004 mg·L^(-1)),DIN和DIP浓度整体自珠江口上游向近海逐渐降低,主要受控于珠江冲淡水,同时受陆架水入侵和浮游植物繁殖消耗等因素影响.春季叶绿素a平均浓度为4.2μg·L^(-1),秋、冬季分别为2.5μg·L^(-1)和2.1μg·L^(-1),均大于1.7μg·L^(-1)(夏季),春、夏季高值区主要位于磨刀门口和万山群岛附近海域,秋、冬季水温升高和上游区域透明度增大,叶绿素a高值区明显北移至万山群岛北侧和上游区域.四季珠江口海域浮游植物繁殖主要是磷限制,且磷限制潜在性富营养状态主要位于伶仃洋海域,自北向南过渡为磷限制中度营养状态,至近海为贫营养状态.The nutrients and other environmental factors in sea water were investigated in the Pearl River Estuary(PRE)and its adjacent sea areas during 2019—2020 for assessment of the influence of El Niño.The rainfall of the pro-flood season(spring)significantly increased in the South China including Guangdong province compared with the perennial data(the multi-year mean).The runoff of the Pearl River into the sea in spring was greater than that in summer,in which the average salinity of 26.56 was lower than that in summer(30.61).However,the rainfall and runoff into the sea in the non-flood seasons(autumn and winter)sharply decreased,resulting to the maximum values of the average salinity in autumn(32.39).Our results show that the mean values of salinity in the different seasons was followed as:autumn(32.39),summer(30.61),and spring(26.56).The mean concentration of dissolved inorganic nitrogen(DIN)was the highest in spring(0.38 mg·L^(-1)),followed by in summer(0.18 mg·L^(-1)),winter(0.16 mg·L^(-1)),autumn(0.08 mg·L^(-1)),respectively.The mean concentration of dissolved inorganic phosphorus(DIP)was the highest in winter(0.009 mg·L^(-1)),followed by in summer(0.006)mg·L^(-1),spring(0.004 mg·L^(-1)),and autumn(0.004 mg·L^(-1)).Our study indicates that the DIN and DIP decreased gradually from the upstream of the PRE to the offshore due to primarily the fresh water of the Pearl River,as well as the invasion of shelf water,and the consumption of phytoplankton reproduction.The mean concentration of Chl-a in spring(4.2μg·L^(-1))was greater than that in summer(1.7μg·L^(-1)),and higher than those in autumn(2.5μg·L^(-1))and winter(2.1μg·L^(-1)).In spring and summer,the high-concentration areas of the Chl-a occurred mainly at the Modaomen estuary and near Wanshan islands,and then moved north to the Pearl River upstream and the north Wanshan Islands in autumn and winter due to the water temperature rising and the upstream transparency increasing.The phytoplankton propagation and its potential eutrophication in the PR

关 键 词：珠江口 营养盐 El Niño 冲淡水 生态响应 

分 类 号：X52[环境科学与工程—环境工程] X824