Survey of Prokaryotic Marine Plankton

虽然原核生物无处不在，在生物学上也非常重要，但海洋群落的多样性几乎是未知的。一个主要障碍是标准鉴定所需的可培育性较差。这个拟议的项目将调查几个海洋地点的浮游原核生物，目的是通过直接从生物质中获得的16S rRNA基因序列对它们进行分类。这种方法提供了一个极其广泛的分类系统发育框架，是现在唯一可以在不培养生物体的情况下使用的方法。这些结果是以序列的形式出现的，通过系统发育分析进行解释。此前，首席调查员和其他人曾将这种方法应用于少数开放海洋样本，并且已经发现了主要的新分类群(例如，一个考古细菌群，其已知近亲在进化上的距离就像动物与植物之间的距离一样远)。其他新的主要分类群，以及特征更好的分类群的更多成员，很可能正在等待发现。拟议的项目将把这些研究扩展到深海、沿海、极地和珊瑚礁栖息地，这些栖息地以前没有以这种方式进行过检查。首席调查员已经收集了大部分样本，资金将用于调查和分析。这些结果可用于对生态学、生物地理学和系统发生学中的假说进行初步检验，但主要将作为未来此类研究的框架。

Although prokaryotes are ubiquitous and immensely important biologically, the diversity of marine communities is almost unknown. A major obstacle is poor culturability required for standard identification. This proposed project will survey planktonic prokaryotes in several ocean locations, with the objective of classifying them by means of 16S rRNA gene sequences obtained direct from biomass. This approach has provided an extremely broad phylogenetic framework of classification, and is the only one that can now be used without culturing the organisms. The results are in the form of sequences, interpreted via phylogenetic analysis. Previously, the Principal Investigator and others have applied this approach to a few open ocean samples, and major new taxa have already been discovered (e.g. an archaebacterial group whose nearest known relatives are as evolutionarily distant as animals are from plants). It is likely that other novel major taxa, as well as additional members of better-characterized ones, are awaiting discovery. The proposed project will extend these studies to deep sea, coastal, polar, and coral reef habitats that have not previously been examined this way. The Principal Investigator has already collected most of the samples, and funds will be used for work- up and analysis. The results can be used in preliminary tests of hypotheses in ecology, biogeography, and phylogeny, but primarily will serve as a framework for future such studies.