Survey of Prokaryotic Marine Plankton

9401110富尔曼尽管原核生物在许多生物过程中无处不在且极其重要，但自然产生的海洋种群的多样性却鲜为人知。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性困难，以及正确分类的问题。这个拟议的更新项目将调查美国和偏远海洋不同地点的浮游原核生物，通过16S rRNA基因序列对它们进行分类。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，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存在，并且在现有大型数据库的背景下通过系统发育分析计算机程序进行解释。以前的工作(在我们的实验室和其他实验室中)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个主要的古细菌组，一些潜在的门或类级真细菌组)。到目前为止，从4个大西洋和太平洋深海样本中检测到的深海克隆中，这种新的古细菌占据主导地位，可能是地球上最丰富的生物群。结果表明，很有可能其他新的主要分类群，以及更多特征更好的分类群，正在等待在尚未研究的地区发现。这项提议是将这些研究的全球覆盖范围扩大到南澳大利亚州(东南印度洋)、格陵兰海、北极海、西北太平洋和西热带太平洋(珊瑚礁)、阿拉伯海(西北印度洋)、南极和墨西哥湾的表层和深水，所有这些水域都远离以前用这种方法检查过的地点。成本效益高的远程采样将由已经为自己的工作研究这些领域的同事进行。还建议对加州沿海水域的不同季节进行重复采样，以涵盖当地微生物组成的时间变化。这些结果可用于检验生态学、生物地理学和系统发育学中的假说，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.