南黄海浮游植物初级生产力粒级结构与碳流途径分析

Size structure and potential export of phytoplankton primary production in the southern Huanghai(Yellow) Sea

根据2006年夏季与冬季南黄海真光层内浮游植物初级生产速率的实测数据,对比研究了两种差异显著的水动力条件下,不同粒级浮游植物初级生产力水平、时空分布特征及其环境调控机制,并探讨了真光层生源碳可能的碳流途径。研究结果表明,南黄海夏季总初级生产力(碳)平均为30.69 mg/(m2.h),高值区位于调查海域南部长江冲淡水影响区,冬季总初级生产力低于夏季,平均水平为21.73 mg/(m2.h),高值区北迁至海州湾附近;夏季不同粒径浮游植物对总初级生产的贡献率由高到低的顺序为小型(42.8%)、微型(29.6%)、微微型(27.6%),冬季的为微微型(41.2%)、微型(36.5%)、小型(22.3%);真光层初级生产力与环境因子的相关分析表明,水动力条件(混合与层化)引起的营养盐来源和光照的变化是初级生产力分布的主要控制因素;用生态比值法对南黄海碳流途径的分析表明,微食物环在冬夏两季碳流途径中均占有重要地位,从总体上看,南黄海浮游生态系统的碳输出潜力较弱。

The distribution and environmental control of total and size-fractionated phytoplankton primary production in the Southern Huanghai（Yellow） Sea were studied based on the investigation conducted under summer stratification and winter mixing conditions in 2006.The mean level of euphotic zone integrated primary production in summer and winter were 30.69 mg/（m^2·h） and 21.73 mg/（m^2·h） respectively.High levels of primary production were observed in the Changjiang River diluted water influenced area in summer,while in winter the high level zone shifted northerly to the adjacent of Haizhou Bay.The relative contributions of different size fractions of phytoplankton were in the sequence of micro（42.8%）〉nano（29.6%）〉pico（27.6%）in summer and pico（41.2%）〉nano（36.5%）〉micro（22.3%）in winter.The relationships between the primary production and environmental factors showed that the variations of nutrients availability and light regimes driven by the hydrodynamic conditions were the main causes of primary production distribution features.The food-web mediated carbon pathway and potential export were also qualitatively analyzed with simple ecological ratios.Microbial food web played important roles both in summer and in winter,and in general the pelagic ecosystem of the southern Huanghai Sea showed a weak carbon export potential.