Weisse Thomas
Research Institute for Limnology, University of Innsbruck, Mondseestraße 9, 5310, Mondsee, Austria.
J Eukaryot Microbiol. 2014 Jul-Aug;61(4):419-33. doi: 10.1111/jeu.12123. Epub 2014 Jun 6.
Application of deep sequencing technologies to environmental samples and some detailed morphological studies suggest that there is a vast, yet unexplored rare ciliate biosphere, tentatively defined in terms of operational taxonomic units. However, very few studies complemented molecular and phylogenetic data with morphological and ecological descriptions of the species inventory. This is mainly because the sampling effort increases strongly with decreasing species abundance. In spite of this limited knowledge, it is clear that species that are rare under certain environmental conditions (temporal rare biosphere) may become abundant when the physical, chemical, and biological variables of their habitat change. Furthermore, some species may always be present in low numbers if their dispersal rates are exceedingly high (accidental rare biosphere). An intriguing question is whether there are some species that are always rare, i.e., in every suitable environment. This permanent rare biosphere is conceptually different from the temporal rare biosphere. This review characterizes typical aquatic habitats of the rare ciliate biosphere, portrays different scenarios under which some or even many species may be permanently rare (background fauna), and identifies some fundamental questions that need to be addressed to achieve a better understanding of the population dynamics of the rare ciliate biosphere.
将深度测序技术应用于环境样本以及一些详细的形态学研究表明，存在一个庞大但尚未被探索的稀有纤毛虫生物群落，暂按操作分类单元来定义。然而，很少有研究将分子和系统发育数据与物种清单的形态学和生态学描述相结合。这主要是因为随着物种丰度的降低，采样工作量会大幅增加。尽管知识有限，但很明显，在某些环境条件下稀有的物种（暂时的稀有生物群落）在其栖息地的物理、化学和生物变量发生变化时可能会变得丰富。此外，如果某些物种的扩散速率极高（偶然的稀有生物群落），它们可能总是以低数量存在。一个有趣的问题是，是否存在一些总是稀有的物种，即在每个适宜环境中都稀有。这种永久的稀有生物群落与暂时的稀有生物群落概念不同。本综述描述了稀有纤毛虫生物群落的典型水生栖息地，描绘了一些或甚至许多物种可能永久稀有的不同情形（背景动物群），并确定了一些为更好地理解稀有纤毛虫生物群落的种群动态而需要解决的基本问题。
