大连湾海域营养盐时空分布、结构特征及其生态响应

Distribution and structure of nutrients in seawater and ecological responses in Dalian Bay

基于2012年夏秋季大连湾海水中溶解态和不同粒级颗粒物中氮、磷、硅、叶绿素a的调查资料,对大连湾海水不同粒级颗粒物中营养盐和叶绿素a的时空分布特征进行了分析,对不同粒级浮游植物的营养要素组成及营养盐结构特征进行了探讨.结果表明,大连湾海水中溶解态营养盐、叶绿素a高值区主要出现在臭水套和甜水套湾附近海域,并由湾内向湾外递减,各粒级颗粒物中营养盐分布趋势存在着不一致性,但高值区易出现在西北部海域;除无机氮外,海水中营养盐总体表现出秋季高于夏季,各粒级叶绿素a浓度表现为夏季高于秋季;磷是大连湾海水中浮游植物生长的限制元素,硅是不同粒级浮游植物营养盐的限制要素;微微型浮游植物对现有的营养结构更具适应性.

Nutrient concentrations in seawater, and content of N, P, Si and chlorophyll a in different-sized particulates were measured in Dalian Bay during the cruises carried in summer and autumn of 2012. The temporal and spatial distributions of nutrients and chlorophyll a were studied, and the nutrient compositions and structures in different-sized fractions of phytoplankton were discussed. The high concentration areas of nutrients and chlorophyll a were usually in Choushuitao Bay and Tianshuitao Bay. The concentration decreased gradually from the inner bay to the outer bay. The distributions of nutrients in different-sized particulates showed no consistent trends, and the concentrations of nutrients in the northwest were higher than the middle of the bay. Seasonal variations in nutrients were higher in autumn than in summer （except DIN）, however the content of chlorophyll a indicated an opposite variation. P was the limiting factor of phytoplankton growth, and Si was the limiting factor of nutrient compositions in different-sized fractions of phytoplankton. Among phytoplankton groups, picophytoplankton growth was the most adaptable in the nutrient structure of Dalian Bay.