2017年长江口海域夏季叶绿素a昼夜动态变化及影响因素  

Diurnal Variation and Influence Factors of Chlorophyll-a in Changjiang River Estuary in Summer of 2017

作　　者：宋绚丽 许永久 俞存根 张洪亮[2] SONG Xuanli;XU Yongjiu;YU Cungen;ZHANG Hongliang(School of Fisheries, Zhejiang Ocean University, Zhoushan, 316022, China;Zhejiang Marine and Fisheries Institute, Zhoushan 316021, China)

机构地区：[1]浙江海洋大学水产学院,浙江舟山316022 [2]浙江省海洋水产研究所,浙江舟山316021

出　　处：《水产科学》2022年第1期52-61,共10页Fisheries Science

基　　金：浙江省自然科学基金资助项目(LY20C030004);浙江省教育厅一般项目(Y201738637);舟山市科技局浙江海洋大学专项(2019C21021);国家海洋局海洋生态环境科学与工程重点实验室开放基金资助项目(MESE-2018-01).

摘　　要：根据2017年夏季长江口海域的两个连续站位的温盐深仪剖面调查及24 h水样的采样数据,获得两个站位的温度、盐度、叶绿素a及营养盐剖面昼夜分布。利用回归分析法,研究各水层环境因子对叶绿素a的影响,建立不同水层叶绿素a变化与环境因子、浮游动物捕食效应的多元回归模型,并探讨长江口海域夏季叶绿素a昼夜动态变化机制。研究结果显示,夏季长江口海域表层受长江冲淡水的影响显著,表层叶绿素a质量浓度下午较高(1.0~7.0 mg/m^(3)),底层叶绿素a受到台湾暖流中下层水团的影响,质量浓度较低(0.2~1.0 mg/m^(3))。相关分析表明,表层叶绿素a的昼夜变化主要受到高营养盐的长江冲淡水、光照度的影响,而底层叶绿素a主要受到潮汐作用和台湾暖流带来的低营养盐水团的周期性影响,两个站位叶绿素a垂直分布、昼夜时间序列分布差异性均不显著(P>0.05)。多元回归分析表明,长江口海域的表层营养盐是影响表层叶绿素a昼夜动态变化的主要因素,而浮游动物捕食作用对叶绿素a的影响并不显著(P>0.05)。潮汐作用带来的盐分和营养物质(Si∶N和N∶P)对底层叶绿素a昼夜变化的影响显著(P<0.05)。According to the 24 h continuous survey of environmental and water profiles in the two stations near the mouth of Changjiang River estuary(CRE)in summer of 2017,the diurnal variations in temperature,salinity,chlorophyll-a(Chla)and nutrient were obtained from conductivity-temperature-depth(CTD)and water samples.Base on the correlation analysis,the influence of environmental factors on Chla short-time dynamics were analyzed in surface and bottom layers,respectively.The multiple regression analysis was used to construct models between Chla level and environmental and biological factors.The results showed that the short-term diurnal time series of surface Chla were strongly affected by the Changjiang River Discharge,with the afternoon highest value period(1.0—7.0 mg/m^(3)),much lower(0.2—1.0 mg/m^(3))bottom Chla,significantly affected by tidal process(periodically),as well as waters from Taiwan Warm Current.The Chla time series in two stations were not significant difference in each layers(P>0.05).Multiple regression analysis revealed that surface nutrients brought by CRE discharge were abundant to supply the phytoplankton growth,and were the main controlling factors for the Chla short-time dynamics.While zooplankton was not the main factor for Chla variation.The bottom Chla variation was significantly influenced by combination of bottom tidal process,Taiwan Warm Current and zooplankton predation(P<0.05).The salinity and nutrients(Si∶N and N∶P)brought periodically by tidal process were contributed significantly to bottom Chla diurnal variations.

关 键 词：叶绿素A 昼夜变化 营养盐 影响因素 长江口海域 

分 类 号：X171[环境科学与工程—环境科学]