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Microbial succession from ice to vegetated soils in response to glacial retreat

冰川退缩导致微生物从冰到植被土壤的演替

基本信息

批准号：
NE/J02399X/1
负责人：
Alexandre Anesio
金额：
$ 72.25万
依托单位：
University of Bristol
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2012
资助国家：
英国
起止时间：
2012 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FJ02399X%2F1
关键词：
Microbial succession ice vegetated soils

项目摘要

When glaciers retreat, their forefields present a unique opportunity to investigate the initial phases of soil formation and microbial succession. As the ice retreats leaving space for microbial and plant colonisation, some studies show evidence of an increase in a variety of microbial proxies, such as nitrogen fixation, microbial enzymatic activity and diversity, in relation to years of exposure until certain soil stability is reached. Surprisingly, very little is known regarding the genetic and functional diversity of microbes in Arctic habitats. The composition and the metabolic potential of the entire microbial population can be explored by isolating and characterising their genetic material recovered directly from the environment using a metagenomic approach. Each sample of a soil habitat analysed represents a snapshot of the complex mixture of different microbial types and some types will be much more abundant than others. For instance, we predict in this project that genes associated with phototrophic C and N fixation and aerobic C metabolism will be predominant at the initial stages of succession in soil after glacial retreat, while deeper soil samples will provide conditions for anaerobic C and N metabolism to develop, include the production and consumption methane, which is a very powerful greenhouse gas. The metagenomic approach can be further linked to rates of metabolism and geochemical characteristics of soils, many of those factors have strong feedbacks with each other. There have been few integrated studies which link microbial diversity to ecosystem function and the biogeochemical cycling of key elements (C, N, Fe). This proposal aims to employ such integrated approach to generate new and uniquely datasets of genetic and functional diversity of representative terrestrial Arctic habitats. The project will instigate a step jump in our understanding of metabolic pathways of terrestrial Arctic habitats to improve biogeochemical models and quantification of the full metabolic package during successional events in soils after glacial retreat. The forefields of 2 glaciers (one in Svalbard and one in Greenland, which represent one small polar system and one major ice sheet, respectively) will be chosen for this project because they provide a range of forefield habitats of different sizes, locations, vegetation and availability of water surrounding the system. Samples for the metagenomic analyses will be taken from representative soils representing different ages of exposure after glacial retreat. We aim to generate several orders of magnitude more primary sequence data than existing metagenome pipelines were originally designed to deal with. This sampling strategy will give us a high-resolution picture of the microbial genetic and metabolic diversity associated with key elements (e.g., C, N, Fe) of glacial forefield habitats, also allowing us to PREDICT changes in metabolic pathways and biogeochemical cycles in response to glacial retreat. The project will instigate a step jump in our understanding of the biodiversity of glacial Arctic terrestrial habitats and provide a database that may be used to interpret data recovered during future. This will ultimately give us valuable insights in relation to the potential for life in other icy planets and moons and during the so called Snowball Earth. Data generated in this proposal can be incorporated into models of carbon, nitrogen, iron and sulphur cycling.

当冰川退缩时，它们的前田提供了一个独特的机会来研究土壤形成和微生物演替的初始阶段。随着冰的消退，为微生物和植物的定植留下了空间，一些研究表明，在达到一定土壤稳定性之前，与暴露多年有关的各种微生物指标，如固氮、微生物酶活性和多样性，都有所增加。令人惊讶的是，人们对北极栖息地微生物的遗传和功能多样性知之甚少。通过使用宏基因组方法直接从环境中分离和表征其遗传物质，可以探索整个微生物种群的组成和代谢潜力。所分析的土壤栖息地的每个样本都代表了不同微生物类型的复杂混合物的快照，有些类型将比其他类型丰富得多。例如，我们在本项目中预测，在冰川退缩后的土壤演替初期，与光合碳氮固定和好氧碳代谢相关的基因将占主导地位，而更深的土壤样品将为厌氧碳氮代谢的发展提供条件，包括甲烷的产生和消耗，甲烷是一种非常强大的温室气体。宏基因组方法可以进一步与土壤的新陈代谢率和地球化学特征联系起来，其中许多因素彼此之间有很强的反馈。将微生物多样性与生态系统功能和关键元素（C、N、Fe）的生物地球化学循环联系起来的综合研究很少。本提案旨在采用这种综合方法来生成具有代表性的北极陆地栖息地遗传和功能多样性的新的独特数据集。该项目将促进我们对北极陆地栖息地代谢途径的理解，以改进生物地球化学模型和冰川退缩后土壤连续事件中全代谢包的量化。两个冰川的前田（一个在斯瓦尔巴群岛，一个在格陵兰岛，分别代表一个小的极地系统和一个主要的冰盖）将被选为这个项目，因为它们提供了一系列不同大小、位置、植被和系统周围水的可用性的前田栖息地。用于宏基因组分析的样品将取自代表冰川退缩后不同暴露年龄的代表性土壤。我们的目标是生成比现有宏基因组管道最初设计用于处理的多几个数量级的初级序列数据。这种采样策略将为我们提供与冰川前野栖息地关键元素（如C、N、Fe）相关的微生物遗传和代谢多样性的高分辨率图像，也使我们能够预测冰川退缩时代谢途径和生物地球化学循环的变化。该项目将促使我们对北极冰川陆地栖息地生物多样性的理解迈出一步，并提供一个数据库，可用于解释未来恢复的数据。这将最终为我们提供宝贵的见解，以了解其他冰冷的行星和卫星以及所谓的“雪球地球”时期存在生命的可能性。该方案中产生的数据可以纳入碳、氮、铁和硫循环模型。