Big River Microbiology: Bacterioplankton Diversity and Community Dynamics of the Six Largest Rivers in the Arctic Ocean Watershed

大河微生物学：北冰洋流域六大河流的浮游细菌多样性和群落动态

• 批准号: 0520480
• 负责人: Byron Crump
• 金额: --
• 依托单位: University of Maryland Center for Environmental Sciences
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-15 至 2008-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0520480&HistoricalAwards=false
• 关键词: Big; River; Microbiology; Bacterioplankton; Diversity

The field of molecular microbial ecology is entering a second age, going beyond simple surveys of diversity and revealing organized patterns of diversity consistent with ecological concepts that were once thought only applicable to 'macroscopic' organisms. Recent discoveries of synchrony among independent microbial communities, taxa-area relationships, and bacterial endemism call for cohesive, large-scale studies of microbial diversity in systems hosting comparable microbial communities. Freshwater bacterioplankton are particularly useful for this purpose because of their relatively restricted diversity and their global distribution. These organisms are ecologically important, catalyzing critical biogeochemical reactions and serving as central members of aquatic microbial food webs. Diversity studies, conducted mainly in lakes, indicate bacterioplankton communities are dynamic, responding to spatial and temporal environmental gradients with shifts in dominant phylotypes. In rivers, such shifts can be rapid and extreme because of short water residence time. This sensitivity makes river bacterioplankton ideal for identifying environmental controls on the composition of microbial communities. Unfortunately, very little is known about the diversity and dynamics of river bacterioplankton. This work will test for hemisphere-scale patterns of bacterial diversity by characterizing and comparing the bacterioplankton diversity of the six largest rivers in the Arctic Ocean watershed, including five of the world's largest rivers (Ob', Yenisey, Lena, Mackenzie, Yukon, and Kolyma rivers), and interpreting these patterns by relating them to an extensive complementary database of physical, chemical and biological measurements. In collaboration with the PARTNERS group (Pan-Arctic River Transport of Nutrients, Organic Matter and Suspended Sediments), and partially funded with "start-up" funds associated with the PI's new faculty appointment, the PI has collected high quality DNA samples from the mouths of these six rivers over a 4 years period beginning in 2003. The overall goal of the PARTNERS project is to use river water chemistry as a tool to study the origins and fates of continental runoff to the Arctic Ocean. Freshwater bacterioplankton may be useful as river-specific genetic tracers freshwater in the Arctic Ocean as they are easily distinguishable from marine bacterioplankton using molecular techniques. The principal investigator proposes to survey Arctic Rivers for abundant, persistent, river-specific bacterial phylotypes, design PCR primers targeting these organisms, and test whether these primers can detect highly dilute freshwater bacteria in the Arctic Ocean. Broader Impacts. Through collaboration with PARTNERS, this project is a multi-national endeavor (USA, Canada, & Russia) that will strengthen international communication. It will also further the knowledge of global microbial diversity, contribute to research on the long-term impacts of climate change on the Arctic, and explore the use of genetic tracers in marine systems. One graduate student will be trained in state-of-the-art molecular techniques and bioinformatics. New discoveries will be incorporated into a graduate-level course entitled Aquatic Microbial Ecology. Data, discoveries and DNA sequences will be posted on the PARTNERS project website and made available for download by the scientific community.

分子微生物生态学领域正在进入第二个时代，它超越了简单的多样性调查，揭示了与曾经被认为只适用于“宏观”生物体的生态概念相一致的多样性的有组织的模式。最近发现的独立微生物群落之间的同步性、类群-区域关系和细菌特有现象，需要对具有可比微生物群落的系统中的微生物多样性进行连贯的、大规模的研究。淡水浮游细菌由于其相对有限的多样性和全球分布而特别适用于此目的。这些生物体具有重要的生态意义，可催化关键的生物地球化学反应，并作为水生微生物食物网的核心成员。主要在湖泊中进行的多样性研究表明，浮游细菌群落是动态的，对空间和时间环境梯度做出反应，并导致优势系统型的变化。在河流中，由于水停留时间短，这种变化可能是快速且极端的。这种敏感性使河流浮游细菌成为识别微生物群落组成的环境控制的理想选择。不幸的是，人们对河流浮游细菌的多样性和动态知之甚少。这项工作将通过表征和比较北冰洋流域六条最大河流的浮游细菌多样性来测试半球尺度的细菌多样性模式，其中包括世界上最大的五条河流（鄂毕河、叶尼塞河、勒拿河、麦肯齐河、育空河和科累马河），并通过将这些模式与物理、化学和生物测量的广泛补充数据库联系起来来解释这些模式。与 PARTNERS 小组（营养物质、有机物质和悬浮沉积物的泛北极河流运输）合作，并获得与 PI 新教职人员任命相关的“启动”资金的部分资助，PI 已从从 2003 年开始，为期 4 年的时间里，对这六条河流的河口进行了研究。 PARTNERS 项目的总体目标是利用河水化学作为工具来研究大陆的起源和命运。流入北冰洋的径流。淡水浮游细菌可用作北冰洋淡水河流特异性遗传示踪剂，因为使用分子技术可以轻松将它们与海洋浮游细菌区分开来。主要研究人员提议调查北冰洋河流中丰富的、持久的、河流特有的细菌系统型，设计针对这些生物的 PCR 引物，并测试这些引物是否可以检测北冰洋中的高度稀释的淡水细菌。更广泛的影响。通过与合作伙伴的合作，该项目是一个跨国项目（美国、加拿大和俄罗斯），将加强国际交流。它还将进一步了解全球微生物多样性，有助于研究气候变化对北极的长期影响，并探索遗传示踪剂在海洋系统中的使用。一名研究生将接受最先进的分子技术和生物信息学培训。新发现将被纳入名为水生微生物生态学的研究生课程中。数据、发现和 DNA 序列将发布在 PARTNERS 项目网站上，并可供科学界下载。