【作者】 孙科；

【导师】 尹宝树； 丘仲锋；

【作者基本信息】 中国科学院研究生院（海洋研究所） ， 物理海洋， 2013， 博士

【摘要】 近年来，长江口及邻近海域富营养化问题日趋严重，赤潮的发生频率逐年增加，规模逐年增大。为了解长江口及邻近海域春季赤潮分布及优势种演替控制机理，本文针对两种东海典型赤潮藻分别建立生长机制模型，利用室内培养实验结果优化高灵敏度参数并完成了对模拟结果的验证。在此基础上，将该模型耦合到水动力模型中，对东海赤潮藻类种群动态进行了模拟，并探讨了光照、温度、盐度及营养盐在东海赤潮高发区春季赤潮生消过程中的作用。研究成果对于揭示东海赤潮发生过程中的控制因素具有重要意义。通过研究取得如下进展：一、以Eco3M为基础，建立了两个针对东海典型赤潮藻—中肋骨条藻与东海原甲藻的生长模型。采用室内实验数据，对模型参数进行校正。模型能够重现两种藻在不同光照、营养盐限制条件下的生长以及对营养盐的利用情况。二、结合两个单藻种模型，对共培养条件下东海原甲藻与中肋骨条藻的生长进行了模拟。结果表明，模型能够重现两种藻在共培养条件下的竞争结果及其对营养盐的竞争吸收情况，但不足以描述营养盐竞争外的藻间相互作用。三、将所建立的两个生长机制模型与物理模型相耦合，较好地重现了2005年温度、盐度以及表层流场，并成功重现了航次重点调查区域内的营养盐变化。通过与遥感图像的对比证明，模拟结果较好地重现了赤潮优势种由硅藻向甲藻的演替趋势以及Chl-a高值区的水平分布。四、分析了相关变量对赤潮藻生长率的影响及其时空变异。结果表明：对于中肋骨条藻，在长江冲淡水影响区域温度、盐度对生长率的影响最强，这种影响主要是由盐度决定的；光照决定了中肋骨条藻生长的内侧边界，而营养盐决定了其生长的外侧边界，其中P限制起主要作用；死亡率对净生长率的影响较小。对于东海原甲藻，N、P共同决定了其生长的外侧边界，其它各因素对生长的影响与中肋骨条藻相似。结果表明，P营养的分布在演替过程中起关键作用。五、数值模拟重现了东海原甲藻从次表层孕育上升到表层爆发赤潮的过程，并通过模拟结果分析了相关变量对生长率垂直分布的影响，结果表明：光照对表层东海原甲藻的生长率影响不大，深层生长率主要受光的限制；表层有一受P限制的低生长率区域，这一区域下方仍然保持着较高的生长率，这可能是东海原甲藻次表层孕育这一现象发生的原因。更多还原

【Abstract】 In recent years, eutrophication has become an overwhelming phenomenon inthe Changjiang estuary and its adjacent area, and harmful algal blooms (HABs) areoccurring more frequently. To understand the mechanism of HABs in theChangjiang estuary and its adjacent area, two box models were built, using thephysiological features of P. donghaiense and S. costatum. The parameters werecalibrated carefully using experimental counterparts and several numericalsimulations were performed to compare the results with laboratory outcomes. Then,the two models were elaborated in ecosystem model focusing on the Changjiangestuary and its adjacent area to research the effects of irradiance, temperature,salinity, and nutrients on the process of blooms in spring. Many results wereobtained which can definitely provide valuable scientific evidence and theoreticalfoundation for revealing the occurrence mechanism of HABs in this area. The resultsare shown as followed:1. Base on the phytoplanktonic part of Eco3M, two box models for typical HABspecies (P. donghaiense and S. costatum) were built. After the calibration ofseveral sensitive parameters, models could reproduce the general characteristicsof algal growth and the use of nutrients under different irradiances andnutritional conditions.2. By coupling two mono-species models, we investigated the utility of mechanismmodels in the research of bi-algal cultures. The simulated results were consistentwith the laboratory findings, indicating that the models could reproduce theresults of nutrient competition between the two algae.The models were limited insimulating interactions besides nutrient competitiondel.3. By coupling the two box models with physical model, the model was in general capable of reproducing observed temperature, salinity, and current. The observedfield of nutrients in the key area was well reproduced. These comparisonsbetween simulated Chl-a and remote-sensing images suggested the model was ingeneral capable of reproducing the horizontal distribution of high concentrationChl-a area and the succession from diatom to dinoflagellate.4. By analyzing the effects of variables on the horizontal variation of growth rate,we find that: For S. costatum, the most influential area of temperature andsalinity is located at Changjiang Diluted Water, and is mainly governed bysalinity. The nearshore and offshore boundary of growth is governed byirradiance and nutrients, respectively. The influential area of nutrients is mainlygoverned by P-limited. The influence of mortality on net growth rate is weak.The influences of variables on dinoflagellate growth are similar with that on S.costatum. The distribution of P was the critical factor during the process ofsuccession.5. We proved the model’s ability to reproduce the process of P. donghaiense bloom,including the incubation at the subsurface layer and the bloom later at thesurface layer. By analyzing the effects of variables on the vertical distribution ofgrowth rate, we found that: For P. donghaiense, the influential area of irradianceis located at deeper water layer. There is an area with low growth rate, which isP-limited, located at the surface layer. However, the growth rate is relativehigher below this area. The simulated results proved this may lead to theincubation at the subsurface layer.更多还原