Survey of Prokaryotic Marine Plankton

虽然原核生物无处不在，而且在生物学上非常重要，但海洋群落的多样性几乎是未知的。一个主要的障碍是标准鉴定所需的培养性差。本项目将调查几个海洋地点的浮游原核生物，目的是利用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，并且是现在唯一可以在不培养生物体的情况下使用的方法。结果以序列的形式，通过系统发育分析来解释。此前，首席研究员和其他人已经将这种方法应用到一些开放的海洋样本中，并且已经发现了主要的新分类群（例如，一个已知最近的亲戚在进化上与动物和植物一样遥远的古细菌群）。很可能还有其他新的主要分类群，以及其他特征更好的分类群，正在等待发现。拟议中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研究。首席研究员已经收集了大部分样本，资金将用于工作和分析。研究结果可用于生态学、生物地理学和系统发育假说的初步检验，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.