Survey of Prokaryotic Marine Plankton

[401110 .福尔曼]虽然原核生物无处不在，在许多生物过程中起着极其重要的作用，但人们对自然发生的海洋种群的多样性知之甚少。其原因包括普遍缺乏可识别的形态差异，标准鉴定所需的可培养性困难，以及关于适当分类的问题。该更新计划将调查美国和偏远海域的浮游原核生物，并通过16S rRNA基因序列对其进行分类。这种方法提供了一个有价值的和极其广泛的分类系统发育框架，并且是目前唯一可以在不培养生物体的情况下完成的方法。结果以易于分布的序列数据的形式出现，并且在大型现有数据库的背景下通过系统发育分析计算机程序进行解释。先前的工作（在我们的实验室和其他实验室）已经成功地将这种方法应用于大约15个海洋样本，并且已经发现了主要的新分类群（例如3个主要的古细菌群，一些潜在的门或纲水平的真细菌群）。到目前为止，在大西洋和太平洋的4个深海样本中，这种新型古细菌在深海克隆中占主导地位，可能是地球上数量最多的生物群。结果表明，在尚未研究的地区，很有可能存在其他新的主要分类群，以及其他特征更好的分类群成员。该提案旨在将这些研究的全球覆盖范围扩大到南澳大利亚（印度洋东南部）、格陵兰海、北极海洋、西北太平洋和西热带太平洋（珊瑚礁）、阿拉伯西海（印度洋西北部）、南极和墨西哥湾的表层和深水，所有这些都远离以前用这种方法研究过的地点。具有成本效益的远程抽样将由已经为自己的工作研究这些地区的同事进行。还建议从加利福尼亚沿海水域的不同季节重复采样，以覆盖当地微生物组成的时间变化。研究结果可用于检验生态学、生物地理学和系统发育方面的假设，但主要将作为未来此类研究的框架。

9401110 Fuhrman Although prokaryotes are ubiquitous and immensely important in numerous biological processes, the diversity of naturally occurring marine populations is poorly known. The reasons for this include a general lack of recognizable morphological differences, difficulties in culturability required for standard identification, and questions about proper classification. This proposed renewal project will survey planktonic prokaryotes in diverse U.S. and remote ocean locations, classifying them by means of 16S rRNA gene sequences. This approach has provided a valuable and extremely broad phylogenetic framework of classification, and is the only one at this time that can be done without culturing the organisms. The results are in the form of readily distributed sequence data, and interpretation within the context of a large existing database is via phylogenetic analysis computer programs. Previous work (in our lab and others) has successfully applied this approach to about 15 marine samples, and major new taxa have already been discovered (e.g. 3 major groups of archaebacteria, a few potentially phylum or class level eubacterial groups). The novel archaebacteria dominate the deep-sea clones from the 4 deep Atlantic and Pacific samples examined so far, and may be the most abundant group of organisms on Earth. Results suggest that it is highly likely that other novel major taxa, as well as additional members of better-characterized ones, are awaiting discovery in regions not yet studied. This proposal is to extend the global coverage of these studies to surface and deep waters of South Australia (SE Indian Ocean), the Greenland Sea, the North Polar Ocean, the Northwestern Pacific and Western Tropical Pacific (coral reef), the Arabian Sean (NW Indian Ocean), the Antarctic, and Gulf of Mexico, all remote from locations that have previously been examined by such approaches. Cost-effective remote sampling will be done by colleagues already studying these areas for their own work. Also proposed is repeated sampling from different seasons in California coastal waters, to cover temporal shifts in local microbial composition. The results can be used in tests of hypotheses in ecology, biogeography, and phylogeny, but primarily will serve as framework for future such studies.