黄海冷水团新生产力及微食物环作用分析

Modelling Study of the New Production and the Contribution of the Microbial Food Loop in the Yellow Sea Cold Water Mass

为了进一步揭示黄海冷水团水域浮游生态系统能流、物流循环的基本动力学特征,利用水层-底栖耦合生态系统垂直3层模型,模拟分析了该水域生源要素的基本特征及年变化特点,并着重分析了初级生产力、新生产力及微食物环作用。通过对黄海冷水团水域初级生产力和新生产力的模拟分析,估算出黄海冷水团年平均初级生产力为228.47mg.m-2.d-1,并根据模型中营养盐的来源估算出f比约为33%。分析模拟结果还表明,在黄海冷水团存在的季节,冷水团水域水层营养盐匮乏,浮游植物生产受限制,仅在晚秋出现了不十分明显的“秋华”。然而,在此时段内,浮游动物的生物量基本和浮游植物为同一量级且量值比较接近,由此可推断微食物环在黄海冷水团能流、物流循环过程中担当了重要的角色。模拟结果表明,浮游动物生长所需的碳约有60%是通过微食物环供给的。与实测及文献结果相比较,模型的模拟结果是合理可信的。

The main purpose of this paper is to better the understanding of the eco-dynamics of the Yellow Sea Cold Water Mass （YSCWM）. The basic characteristics and seasonal variations of biogenic elements in the YSCWM are simulated and analyzed in this paper by using a one-dimensional coupled pelagic-benthic three-box ecosystem model based on in situ observations during June 2000 to July 2001. The model is vertically divided into three boxes according to the depths of the thermocline and the euphotic layer. Based on the modelling analysis of the primary productivity and new production as well as the effect of the microbial loop, it is found that both the primary productivity and new production remain at a low level in the YSCWM. The simulated annual mean primary productivity is 228.47mg· m^-2 ·d^-1 and the new production is about 30 % of the total primary productivity in the YSCWM. The oligotrophic shelf ecosystem features of the YSCWM are simulated well based on comprehensive observation analysis, it is found that a weak phytoplankton bloom occurs in autumn in the YSCWM but the zooplankton biomass remains at quite a high level in summer and autumn and the values are close to the phytoplankton biomass, so that our conclusion is that the microbial loop plays a crucial role in zoo- plankton growth in the YSCWM. Quantitative analysis reveals that the contribution from the microbial loop to the zooplankton productivity can reach up to 60 % in the YSCWM area.