LEXEN: Protistan Biodiversity in Antarctic Marine Ecosystems: Molecular Biological and Traditional Approaches

极端环境微生物多样性的分析是困难的，因为传统的多样性检测方法对于评估这些群落内的物种丰富度往往是无效的。由于在样品收集和处理过程中难以重现和维持相关的环境特征，因此会出现额外的困难。本文研究了南极罗斯海海冰、沉积物和海洋环境中的原生生物组合（藻类和原生动物）。传统上，鉴定自然组合中的原生生物需要直接的显微分析以及用于评估生物多样性的富集和培养技术。因此，这些组合多样性的测定容易受到取样、富集和培养的影响，以及样品保存和显微镜浓缩造成的选择性损失。本项目的目标是：(1)开发和应用分子生物学方法来评估海水、海冰和沉积物环境中小型原生生物（藻类和小于100微米的原生动物）的物种多样性；(2)在适当的温度条件下获得培养原生动物的生长速率、摄食速率和生长效率的基本生理信息。分子生物学研究将涉及使用基于聚合酶链反应的方案来检查小亚基核糖体RNA基因（srDNA）多样性。所开发的方法和技术将适用于任何其他水体或沉积物，并将提供一种方法来检查现有文化收藏中原生生物文化的代表性。* * *

*** Caron 9714299 The analysis of microbial biodiversity of extreme environments is difficult because traditional methods for examining diversity are often ineffective for assessing species richness within these communities. Additional difficulties arise due to the difficulties of recreating and maintaining pertinent environmental features during sample collection and procession. This study focuses on the protistan assemblages (algae and protozoa) in the sea ice, sediment and ocean environments of the Ross Sea, Antarctica. The identification of protistan species in natural assemblages traditionally has entailed direct microscopical analyses as well as enrichment and culture techniques for assessing biodiversity. Determination of diversity for these assemblages in therefore susceptible to biases as a consequence of sampling, enrichment and culture, as well as selective losses due to sample preservation and concentration for microscopy. The goals of this project are: (1) to develop and apply molecular biological approaches to assess species diversity of small protists (algae and protozoa smaller than 100 micrometers) in ocean water, sea ice and sediment environments and (2) to obtain baseline physiological information on the growth rates, feeding rates and growth efficiencies of cultured protozoa under pertinent temperature regimes. Molecular biological studies will involve the use of PCR-based protocols to examine small subunit ribosomal RNA gene (srDNA) diversity. Approaches and techniques developed will be applicable to any other water body or sediment and would provide a means to examine the representativeness of protistan cultures in extant culture collections. ***