Emiliana huxleyi: Role of the Scaled Flagellate in the Lifecycle and Bloom Dynamics

自从它起源于更新世晚期以来，埃米利亚尼亚·赫胥黎在世界海洋中无处不在。它是最丰富的活球石藻，也是大气中二氧化碳向海洋沉积物转移的最重要的生物。形态形态包括含球粒细胞和裸球粒细胞，鳞状鞭毛虫。在自然样本中，只有含球石的形态是容易识别的，迄今为止所有关于该物种分布和丰度的研究都只是对这种形态的研究。与其他颗石藻的比较表明，运动形式是一个交替的生命周期阶段，但对埃米利亚海克斯利的生命周期仍知之甚少，其在开花动力学中的作用尚不清楚。最近发展的技术允许在自然种群中识别和跟踪裸和鞭毛赫胥黎细胞，并简化了培养细胞倍性的测定。本研究的目的是：(1)比较花前、花中和花后自然种群中鞭毛形态和球虫形态的丰度和分布；(2)确定倍性和生活史；从而(3)确定鞭毛形态和性重组在花动力学中的作用。

Since its origin in the late Pleistocene, Emiliania huxleyi has become ubiquitous in the world's oceans. It is the most abundant living coccolithophore and the most important organism in the transfer of atmospheric carbon dioxide to the ocean sediments. Morphological forms include coccolith-bearing and naked coccoid cells, and scaled flagellates. Only the coccolith-bearing morphotype is readily idnetifiable in natural samples, and all studies to date on the distribution and abundance of the species have been studies of only this morphotype. Comparison to other coccolithophores suggests the motile form is an alternate life cycle stage, but the life cycle of Emilianian hyxleyi remains poorly understood, and its role in bloom dynamics is unknown. Recently developed techniques permit identificaiton and tracking of naked and flagellated Emiliiania huxleyi cells in natural populations and simplify determination of ploidy in cultured cells. The objectives of this research are (1) to compare the abundances and distributions of the flagellated form to that of the coccoid forms in natural populations before, during and after blooms, (2) to estabilish ploidy and the life history, and thus (3) to determine the role of the flagellated form, and of sexual recombination, in bloom dynamics.