DIMENSIONS: COLLABORATIVE RESEARCH: GENETIC, PHYLOGENETIC, AND FUNCTIONAL MICROBIAL DIVERSITY IN PERMANENTLY FROZEN AQUATIC SEDIMENTS OVER GEOLOGICAL TIME

永久冻土(永久冻土)可以提供古代生命的快照，并代表植物、动物和微生物群落的化石档案。微生物之所以特别令人感兴趣，是因为与大多数动植物不同，它们可以在极端条件下生存很长一段时间。因此，永久冻土中的一些微生物可能不是化石，但仍然活着--本质上是活的化石。这项研究解决了一个悬而未决的问题，即埋藏在永久冻土中的微生物是否已经灭绝，代表着随着时间的推移而保存下来的古老陆地表面或海洋群落，还是自被埋葬以来一直在进化的活跃的生命群落。为了确定微生物群落可以在永久冻土中生存多长时间，该项目将研究从西伯利亚发现的北半球已知最古老的沉积物中收集的永久冻土。这些有趣的海洋和湖泊沉积物有5000到300万年的历史，在层状悬崖中被发现。这个项目将帮助科学家了解生物群落如何应对环境的巨大变化，其结果将与大学生和高中教师和学生分享。这个为期五年的项目将记录分类、遗传和功能生物多样性随时间的演变，结合单细胞基因组、培养研究和永久冻土沉积物的物理化学特征。该项目的关键挑战之一将是将进化模型应用于DNA序列数据集，以区分包含化石档案模型的永久冻土层与当代群落模型。这些数据将阐明形成分类、遗传和功能多样性的进化机制，为基因组进化和微生物对低温的适应提供洞察。功能、种群遗传和系统发育方法将整合在一起。该项目的国际性提供了一个平台，通过开放系统的数据管理和共享，扩大合作的多年冻土研究网络。该项目将培训本科生、研究生和博士后水平的科学家，并通过分子生物学研讨会聘请高中教师。与俄罗斯合作者的互动和前往西伯利亚研究地点将促进国际合作，并为学生提供如何与来自不同文化的同事进行研究的培训。

Permafrost (permanently frozen soil) may provide snapshots of ancient life and represent fossil archives of plant, animal and microbial communities. Microbes are of particular interest because, unlike most animals and plants, they can survive very long periods of extreme conditions. Therefore, it is possible that some microbes in permafrost are not fossils but are still alive -- essentially, living fossils. This research addresses an unresolved question of whether microbes embedded in permafrost are extinct, representing ancient terrestrial surface or marine communities preserved through time, or actively living communities that have been evolving since being buried. To determine how long microbial communities can live in permafrost, this project will study permafrost collected from the oldest known sediments of the Northern Hemisphere, which occur in Siberia. These intriguing marine and lake sediments are five thousand to three million years old and are found in stratified cliffs. This project will help scientists understand how biological communities respond to large changes in the environment, and its results will be shared with university students and high school teachers and students.This five year project will document evolution of taxonomic, genetic and functional biodiversity over time using state of the art "omic" approaches combined with single cell genomic, cultivation studies and physical-chemical characterization of permafrost sediments. One of the key challenges of this project will be the application of evolutionary models to the DNA sequence datasets to distinguish between permafrost strata containing fossil archive models versus contemporary community models. The data will elucidate evolutionary mechanisms that shape taxonomic, genetic and functional diversity, providing insight into genome evolution and microbial adaptation to low temperatures. Functional, population genetic and phylogenetic approaches will be integrated. The international nature of this project provides a platform to expand a network of collaborative permafrost research with open system data management and sharing. This project will train scientists at the undergraduate, graduate and post-doctoral levels, and engage high school teachers through molecular biology workshops. Interaction with Russian collaborators and travel to the Siberian study sites will promote international cooperation and provide training to students in how to conduct research with colleagues from different cultures.