东海原甲藻赤潮的垂向发展过程:生物-物理耦合数值模拟

近年来，东海原甲藻赤潮在我国东海近岸海域频繁发生。本研究利用生物-物理耦合模型对发生于2005年的东海原甲藻赤潮进行后报模拟，并对控制其起始与发展的因素展开研究。该模型由东海原甲藻种群动力学模型与多层嵌套的水动力模型组合。通过对比模拟结果与室内实验结果，证实种群动力学模型能够很好地重现东海原甲藻在不同光照与磷营养限制条件下的生长过程，同时能够再现藻细胞内部磷含量及藻类对外部营养盐浓度的影响。耦合模型能够较好地再现模拟海域水动力（见Sun et al.，2016）与东海原甲藻赤潮的时空分布。模拟的赤潮发展过程与此前研究中的观测结果一致，且模拟结果表明模型能够捕捉到赤潮初期种群的次表层孕育现象。随后模拟结果被用于诊断决定赤潮垂直分布的决定性因素，结果表明磷酸盐是控制这一现象的关键因素。同时，表层风场在决定赤潮的分布中扮演着重要角色。模拟结果强调了营养盐限制在东海原甲藻次表层孕育及消散过程中的作用，本文所建立的耦合模型需要进一步优化并应用于其它条件下东海原甲藻赤潮的研究中。

Vertical development of a Prorocentrum donghaiense bloom in the coastal waters of the East China Sea:coupled biophysical numerical modeling

Algal blooms caused by Prorocentrum donghaiense occurred frequently in the East China Sea (ECS) during spring in recent years. In this study, a coupled biophysical model was used to hindcast a massive P. donghaiense bloom that occurred in 2005 and to determine the factors influencing bloom initiation and development. The model comprised the Regional Ocean Modeling System tailored for the ECS that utilized a multi-nested configuration and a population dynamics model for P. donghaiense. Comparisons between simulations and observations revealed that the biological model is capable of reproducing the characteristics of P. donghaiense growth under different irradiances and phosphorus limitation scenarios. The variation of intracellular phosphorus and the effects of P. donghaiense on ambient nutrients conditions were also reproduced. The biophysical model hindcasted the hydrodynamics and spatiotemporal distributions of the P. donghaiense bloom reasonably well. Bloom development was consistent with observations reported in earlier studies. The results demonstrate the capability of the model in capturing subsurface incubation during bloom initiation. Then model''s hindcast solutions were further used to diagnose the factors controlling the vertical distribution. Phosphate appeared to be one of the factors controlling the subsurface incubation, whereas surface wind fields played an important role in determining P. donghaiense distribution. The results highlight the importance of nutrient-limitation as a mechanism in the formation of P. donghaiense subsurface layers and the dispersing of P. donghaiense blooms. This coupled biophysical model should be improved and used to investigate P. donghaiense blooms occurring in different scenarios.