Overlap and discrepancies between ecotypes, genotypes and morphotypes of Antarctic and Arctic nanofauna

异养型纳米鞭毛虫是极地地区细菌的主要消耗者，并对从DOC通过细菌到较大生物（如纤毛虫和后生动物）的碳通量做出了重大贡献。海冰中的异养鞭毛虫生物量可能大大超过细菌生物量。根据我们最近对南极和北极纳米动物的分子生物学和形态学研究，形态学调查显示这些微小生物的分类分辨率有限（主要是2-8um细胞大小）。许多形态型包含多个基因型，有时具有很高的进化距离（SSU rDNA的p-距离）。为了研究极地水域特有的作用，我们希望分析所选纳米鞭毛虫的形态型、基因型和生态型之间的差异和重叠，从而得出关于温度微小变化对敏感的南极和北极冰生物群可能产生的影响的结论。我们将从南极和北极采集样本，建立纳米鞭毛虫培养，并结合形态学、分子生物学和生态学方法对其进行分析。除了已经建立的南极和北极分离株培养物外，我们将使用新的克隆培养物来研究单一基因型对温度、盐度和食物成分的耐受性。更多地了解南极和北极生态系统中最重要的细菌组成部分的生物多样性的作用，应该有助于我们对极地地区生态过程的理解。

Heterotrophic nanoflagellates are major consumers of bacteria in the polar regions and contribute significantly to the carbon flux from DOC via bacteria to larger organisms such as ciliates and metazoans. Heterotrophic flagellate biomass may greatly exceed bacterial biomass in the sea ice. According to our recent molecular biological and morphological studies of Antarctic and Arctic nanofauna, morphological investigations reveal only limited taxonomic resolution for these tiny organisms (mainly 2-8um cell size). Many morphotypes contain several genotypes with sometimes high evolutionary distances (p-distances of SSU rDNA). To study the role of endemism in polar waters, we want to analyze discrepancies and overlaps between morphotypes, genotypes and ecotypes of selected nanoflagellates to draw conclusions regarding the possible effects of small changes in temperature on the sensitive Antarctic and Arctic ice biota. We will take samples from Antarctic and Arctic sites, establish cultures of nanoflagellates and analyse them combining morphological, molecular biological and ecological methods. We will use new clonal cultures in addition to already established cultures of Antarctic and Arctic isolates to study the tolerance of single genotypes regarding temperature, salinity and food composition. Knowing more about the role of biodiversity of the most important bacterivorous components of Antarctic and Arctic ecosystems should support our understanding of ecological processes in polar regions.