长江口及邻近海域溶解态锰的分布及影响因素

Distributions and Influence Factors of Dissolved Manganese in the Changjiang Estuary and Its Adjacent Area

为研究陆架边缘海锰的生物地球化学循环,利用隐色孔雀绿-高碘酸钠催化动力学方法,对2012-03和2012-07长江口及其邻近海域调查航次采样的溶解态锰浓度进行测定。2012-03长江口及其邻近海域表、底层水体中溶解态锰浓度没有显著性差异。2012-07底层溶解态锰浓度显著高于表层。溶解态锰浓度存在显著的季节差异,2012-07平均浓度显著高于2012-03的。春、夏季溶解态锰浓度在表、底层分布整体上均呈现出由近岸到外海逐渐降低的特征,表明近岸受到河流输入的影响。2012-03长江口及其邻近海域溶解态锰基本表现为保守混合,2012-07盐度2～8海域表层发生明显的清除。两端元混合模型及相关性分析表明,该海域悬浮颗粒物（SPM）是溶解态锰的一个主要汇。此外,水团的物理混合是影响该海域溶解态锰分布的主要因素。

2 cruises were carried out in March and July 2012 in the Changjiang Estuary and its adjacent area in order to study the biogeochemical cycle of manganese in marginal seas.The concentrations of dissolved manganese were measured by Leucomalachite Green-sodium Periodate Catalytic Kinetic Spectrophotometry.There were no significant difference between the concentrations of dissolved manganese in the surface and bottom waters in March 2012.While in July,the concentrations in the bottom were obviously higher than that in the surface.There were significant seasonal variations between the two cruises,with the higher average concentrations in July than in March.The concentrations of dissolved manganese in both surface and bottom waters decreased from the coastal area to the shelf region during the 2cruises,with high concentrations occurred in the Changjiang Estuary,suggesting that it was affected by the river input.The behavior of dissolved manganese in the Changjiang Estuary and its adjacent area was mainly conservative in March.On the contrary,it was significantly scavenged from surface waters where the salinity ranged from2 to 8in July.SPM was the primary sink of dissolved manganese in this area by the 2end-members mixing model and correlation analysis.In addition,Water masses mixing was the main factor affecting the concentrations and distributions of dissolved manganese in the study area.