桑沟湾溶解态铝的分布、季节变化及影响因素

The Distributions,Seasonal Variations and Influence Factors of Dissolved Aluminum in the Sanggou Bay

基于2011-04,2011-08,2011-10和2012-01对桑沟湾海域大面调查的资料,利用改进的荧光镓(LMG)分子荧光光谱分析法测定溶解态铝的含量,研究了桑沟湾溶解态铝的分布和季节变化特征。结果表明,4个航次桑沟湾溶解态铝的平均浓度分别是(47.3±14.4),(56.0±14.6),(64.5±11.3)和(32.1±6.0)nmol/L,呈现出明显的季节变化,即秋季最高,夏季、春季次之,冬季最低。除几个异常站位外,溶解态铝的分布大致呈现随离岸距离的增加其浓度逐渐降低的趋势。夏季表层溶解态铝的浓度在近岸出现低值,夏、秋季湾口北部均出现高值。影响桑沟湾溶解态铝分布的主要因素包括与黄海的水交换、河流及地下水、浮游植物和养殖生物、悬浮颗粒物。根据简单箱式模型对桑沟湾溶解态铝的通量进行了估算,结果显示,除了河流和大气沉降外,桑沟湾溶解态铝还存在其他的源。与相邻的爱莲湾和俚岛湾相比,桑沟湾溶解态铝的浓度在春季较高,在夏季较低。与世界大洋相比,桑沟湾溶解态铝的浓度全年均较高。

The distributions of dissolved aluminum in the Sanggou Bay were investigated in April,August,October 2011 and January 2012.The concentrations of dissolved aluminum were measured by the modified lumogallion fluorescent method.The average concentrations of dissolved aluminum were（47.3±14.4）nmol/L in April,（56.0±14.6）nmol/L in August（64.5±11.3）nmol/L in October and（32.1±6.0）nmol/L in January,respectively.There existed a significant seasonal variations,with highest in autumn,followed by lower in summer and spring,lowest in winter.In addition to few abnormal stations,the concentrations of dissolved aluminum decreased with the increasing distance from the coast.In summer,the concentration of dissolved aluminum on the surface were lower in the coastal area of the bay.In summer and autumn,the concentration of dissolved aluminum were both higher in the northeast parts of the bay.The influencing factors of dissolved aluminum included the water exchange with Huanghai Sea,river runoff,groundwater,aquaculture,phytoplankton and suspended particulate matter in the water.A preliminary box model was established to estimate the water-mass balance and budgets of dissolved aluminum for the Sanggou Bay,which demonstrated that in addition to riverine inputs and atmospheric depositions,dissolved aluminum had other sources in the Sanggou Bay.The concentrations of dissolved aluminum in the Sanggou Bay were higher in spring,but lower in summer compared with those in the Ailian Bay and the Lidao Bay,and it was all higher compared to the levels of the world oceans throuout the year.