Bacterial Diversity Patterns along Gradients of Primary Productivity in Freshwater Ecosystems

“淡水生态系统中初级生产力梯度上的细菌多样性模式”生命最引人注目的方面之一是它在地球上的分布不均匀。有些地区(如低地地区和热带地区)动植物的多样性很高；另一些地区(如山顶和极地地区)似乎几乎没有生命。可用环境能源的差异是造成这种模式的主要原因。然而，目前尚不清楚地球上最大的生物群体(微生物)的多样性是否也会随着可用能源的不同而变化。初步观察表明，水生生态系统中细菌多样性与有效环境能量之间可能存在一定的关系。该项目的目标是验证这些初步观察结果。更具体地说，将在可用能量不同的池塘中估计细菌多样性。由于环境样本中的大多数细菌不能在实验室中生长，因此将使用在实验室条件下不需要细菌生长的分子技术来评估细菌多样性。细菌多样性将通过从池塘样本中提取细菌核糖体基因并对这些基因进行测序来估计。细菌的分类多样性将从这些基因的序列多样性中估计出来。还将通过从池塘样本中提取amoA基因并对其进行测序来估计单个细菌功能群内的多样性。Amoa基因是氧化氨的细菌所特有的。这些细菌的多样性将从这些基因的序列多样性中估计出来。这项研究将是沿着可用能量梯度测量细菌多样性的第一次全面尝试。它有可能产生关于微生物分布的基本新知识，并可能影响环境管理和寻找新药物等各种领域。

"Bacterial diversity patterns along gradients of primary productivity in freshwater ecosystems" One of the most striking aspects of life is that it is distributed unevenly across the Earth. Some regions (such as lowland areas and the tropics) have a high diversity of plant and animal life; others (such as mountain tops and the polar regions) appear nearly devoid of life. Differences in available environmental energy are a major cause of such patterns. However, it is unknown whether the diversity of the largest group of organisms on Earth (microorganisms) also varies with available energy. Preliminary observations suggest that a relationship may exist between bacterial diversity and available environmental energy in aquatic ecosystems. The goal of this project is to verify these preliminary observations. More specifically, bacterial diversity will be estimated in ponds that differ in available energy. Because most bacteria from environmental samples cannot be grown in the laboratory, bacterial diversity will be assessed using molecular techniques that do not require bacterial growth under laboratory conditions. Bacterial diversity will be estimated by extracting bacterial ribosomal genes from pond samples and sequencing these genes. Bacterial taxonomic diversity will be estimated from the sequence diversity of these genes. The diversity within a single bacterial functional group also will be estimated by extracting and sequencing amoA genes from pond samples. The amoA gene is unique to bacteria that oxidize ammonia. The diversity of these bacteria will be estimated from the sequence diversity of these genes. This study will be the first comprehensive attempt to measure bacterial diversity along a gradient of available energy. It has the potential to generate fundamental new knowledge concerning the distribution of microorganisms and could impact fields as diverse as environmental management and the search for novel pharmaceuticals.