东海卡盾藻的形态与分子遗传特征及生活史研究

Chattonella spp. are extremely noxious species causing harmful algal blooms in marine ecosystems. The globally expanding Chattonella blooms have led to a large economic loss for the marine aquaculture in coastal water. Chattonella blooms have also occurred frequently in the coastal water of China except for the East China Sea (ECS). However, few detailed and deep studies are performed in its taxonomy, which creates great difficulties in those blooms detection and researches in China. In addition, intense controversy continues in the taxonomic study of this genus. It is partly due to the insufficiency in the description of species characteristic and taxonomic property. In this program, multiply traditional morphology and modern molecular methods will be applied and life cycle researches will be conducted in the description of species characteristics of the ECS strains that have been cultured in the lab and that will be isolated from the field samples (water column and sediment). And then, a taxonomic characteristic system for the ECS strains of Chattonella will be established. This will help to enrich the description of the Chattonella species characteristics and reduce the uncertainties in its taxonomy. Meanwhile, combined with physiological ecology researches, we will present some explanations from the perspectives of species characteristic and physiological ecology for why there is no Chattonella blooms occurred in the ECS, and then provide scientific evidences to early warning of those blooms.

卡盾藻(Chattonella)是海洋中一类危害十分严重的赤潮藻，其赤潮呈现出全球化扩展趋势，已经给沿海养殖业造成了巨大的经济损失。在中国沿海(除东海外)也曾数次发生卡盾藻赤潮，然而仍然缺乏详尽深入的分类学研究，这给卡盾藻赤潮的检测和研究带来了困难。同时国际上对该属物种的分类也存在着激烈的争议，部分归因于卡盾藻物种特征描述及分类依据的不完全。本项目对东海已经纯化的卡盾藻藻株和拟通过水采分离和沉积物孢囊萌发两种方法获得的卡盾藻藻株，运用多种传统形态学和现代分子遗传学手段以及整合生活史分析，多角度地对其分类特征展开研究，建立东海卡盾藻分类特征体系。这有助于丰富卡盾藻物种特征描述和降低其分类的不确定性。同时结合生理生态研究，为到目前为止为何东海没有发现/发生卡盾藻赤潮作出一些物种特性和生理生态上的解释，从而为该类赤潮的预警提供科学依据。

卡盾藻(Chattonella)是海洋中一类危害十分严重的赤潮藻，其赤潮呈现出全球化扩展趋势，已经给沿海养殖业造成了巨大的经济损失。在中国沿海(除东海外)也曾数次发生卡盾藻赤潮，然而仍然缺乏详尽深入的分类学研究，这给卡盾藻赤潮的检测和研究带来了困难。我们对分离之东海以及南海和黄海的卡盾藻藻株进行了形态学和分子生物学分析。通过野外调查和室内培养实验未发现其孢囊存在。通过形态观察和基因序列分析实验发现海洋卡盾藻、古老卡盾藻、卵圆卡盾藻在分子遗传上不存在种间区别，但在形态上这三者存在明显的差异。通过连续培养观察发现在海洋卡盾藻的一系列生长过程中，细胞经历了多种形态的变化，最为重要的是通过其生活史的分析发现其生活史远比之前报道的要复杂。其中有趣的是细小孢子繁殖模式，合子细胞可以产生数量巨大的可游动细小孢子，细小孢子是否可以通过培养成长为正常游动细胞还在继续研究中。其它如出芽生殖和连续分裂也是第一次被观察到。本项目通过形态学和分子生物学的方法建立了东海卡盾藻分类特征体系。通过培养实验还发现不同卡盾藻藻株有着不同的最适生长温度，这为东海未发生卡盾藻赤潮的原因提供了一些解释。