Nitrogen fixation and its coupling to methane dynamics in the peat moss (Sphagnum) phytobiome of northern peatlands

北部泥炭地泥炭藓（Sphagnum）植物生物群落中的固氮及其与甲烷动力学的耦合

• 批准号: 1754756
• 负责人: Joel Kostka
• 金额: $ 115万
• 依托单位: Georgia Tech Research Corporation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1754756&HistoricalAwards=false
• 关键词: Nitrogen; fixation; its; coupling; methane

Peatlands are wetlands that lock away huge amounts of carbon as thick peat soil deposits. Referred to as a "carbon bank", scientists believe that the carbon stored in peat is at risk of being released to the atmosphere in response to environmental change. Mosses often dominate plant production in peatland ecosystems, which are concentrated in northern regions where the environment can become extremely cold and is nutrient poor. Similar to humans or to other plants, mosses contain a diverse microbiome, microbes that are intimately associated with the plant in a symbiotic relationship, that help the host to grow and thrive under extreme conditions. The plant host provides the microbiome with a stable environment in which to live and in turn the microbes are believed to help mosses acquire nutrients such as nitrogen and carbon. For example, some microbes convert nitrogen gas from the atmosphere into a form that moss plants can use. Similarly, there are microbes that can also help mosses acquire carbon from the conversion of methane (natural gas produced in wetland soils) to carbon dioxide. This research will determine how much and how fast nitrogen and carbon are metabolized by peat moss microbiomes, as well as the implications for the growth of peat mosses and carbon storage in northern peatland ecosystems in Minnesota and Canada. Taking advantage of a large whole ecosystem experiment, the project will further examine the response of peat mosses and their constituent microbiomes to environmental change. This project will provide fundamental research on how microbiomes aid the growth of peat moss plants, which may store more carbon than any other plant on Earth. Results of the project will be used to improve predictions on whether peatlands will act as a net carbon source or sink in response to ongoing environmental change as well as the potential use of plant microbiomes as a natural biofilter for methane produced in landfills. This research will also serve society by teaching the next generation of scientists about the important ecosystem services that wetlands provide and the role of microbes in maintaining these services. At least two graduate students, two undergraduate students, and a postdoctoral researcher will be involved in all aspects of the project. Two signature activities will be used as instruments to communicate project results to the public. A 5-day workshop in a Georgia wetland will train 16 middle and high school teachers on developing lesson plans for teaching ecosystem science in the context of conservation, restoration, and global environmental change. Project results will be disseminated to the public through an annual interactive activity at the Atlanta Science Festival (which reaches 20,000 people per year).The overall goal of the research is to investigate the role of the peat moss microbiome in regulating peatland carbon (C) and nitrogen (N) cycles and the resilience of peatlands to environmental change. Objectives are to: 1) quantify in situ rates of nitrogen fixation and methanotrophy, and elucidate the contribution of keystone microbial associates mediating these processes in the peat moss microbiome, 2) determine the response of nitrogen fixation and its coupling to methane(CH4) dynamics to perturbation of environmental change drivers in the laboratory and in a large-scale whole ecosystem experiment in the field, and 3) leverage datasets from two long-term field sites to estimate the microbiome contribution to ecosystem N and C budgets as well as model the response of microbiome function to perturbation of environmental change drivers. Working hypotheses include: H1: N fixation is a predominant N input to northern peatlands; H2: The dominant nitrogen fixers are methanotrophic bacteria and cyanobacteria; H3: Methanotrophs that also fix N represent a substantial CH4 sink; H4: Net primary production by peat mosses is directly supported by N acquired from nitrogen fixation and methane-derived C from methanotrophy; H5: Peat moss productivity and its response to environmental perturbations will be largely determined by plant-microbe and microbe-microbe interactions; H6: Increases in temperature and CO2 will result in lower rates of N fixation due to decreased peat moss productivity.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

泥炭地是一种湿地，可以将大量的碳作为厚厚的泥炭土壤沉积物锁住。科学家们认为，储存在泥炭中的碳有被释放到大气中的风险，以应对环境变化。在泥炭地生态系统中，苔藓经常主导植物生产，泥炭地生态系统集中在北部地区，那里的环境可能变得极端寒冷，营养贫乏。与人类或其他植物类似，苔藓包含一个多样化的微生物群，这些微生物与植物密切相关，以共生关系，帮助宿主在极端条件下生长和茁壮成长。植物宿主为微生物群提供了一个稳定的生存环境，反过来，微生物被认为有助于苔藓获得氮和碳等营养物质。例如，一些微生物将大气中的氮气转化为苔藓植物可以使用的形式。同样，也有微生物可以帮助苔藓从甲烷(湿地土壤中产生的天然气)转化为二氧化碳的过程中获得碳。这项研究将确定泥炭苔藓微生物代谢氮和碳的数量和速度，以及对明尼苏达州和加拿大北部泥炭地生态系统中泥炭苔藓的生长和碳储存的影响。利用一个大型的全生态系统实验，该项目将进一步研究泥炭苔藓及其组成微生物对环境变化的反应。这个项目将提供关于微生物如何帮助泥炭苔藓植物生长的基础研究，泥炭苔藓植物可能比地球上任何其他植物储存更多的碳。该项目的结果将用于改善对泥炭地是否将作为净碳源或碳汇的预测，以应对持续的环境变化，以及将植物微生物群用作垃圾填埋场产生的甲烷的天然生物过滤器的潜在用途。这项研究还将通过向下一代科学家传授湿地提供的重要生态系统服务以及微生物在维持这些服务中的作用来服务于社会。至少两名研究生、两名本科生和一名博士后研究员将参与该项目的所有方面。两项签名活动将被用作向公众传达项目成果的工具。在佐治亚州湿地举行的为期5天的研讨会将培训16名初中和高中教师，培训他们在保护、恢复和全球环境变化的背景下，为教授生态系统科学制定教案。项目成果将通过亚特兰大科学节(每年有2万人参加)的年度互动活动向公众传播。研究的总体目标是调查泥炭苔藓微生物群在调节泥炭地碳(C)和氮(N)循环中的作用，以及泥炭地对环境变化的适应能力。目标是：1)量化原位固氮和甲烷营养速率，并阐明Keystone微生物在泥炭苔藓微生物群中调节这些过程的贡献；2)在实验室和野外大型全生态系统实验中确定固氮及其与甲烷(CH4)的耦合动力学对环境变化驱动因素扰动的响应；3)利用两个长期野外站点的数据来估计微生物组对生态系统N和C收支的贡献，并模拟微生物组功能对环境变化驱动因素扰动的响应。工作假设包括：H1：N固定是北部泥炭地的主要N输入；H2：主要的固氮者是甲烷营养细菌和蓝藻；H3：也固定N的甲烷硝化菌代表大量的CH4汇；H4：泥炭苔藓的净初级生产直接得到来自固氮的N和来自甲烷养殖物的甲烷C的支持；H5：泥炭苔藓的生产力及其对环境扰动的反应将在很大程度上由植物-微生物和微生物-微生物相互作用决定；H6：由于泥炭苔藓生产力的下降，温度和二氧化碳的增加将导致更低的固氮率。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Draft metagenome sequences of Sphagnum (peat moss) from ambient and warmed environments across Europe

来自欧洲周围和温暖环境的泥炭藓（泥炭藓）宏基因组序列草案

• 发表时间: 2022
• 期刊: Microbiology resource announcements
• 影响因子: 0.8
• 作者: Bryan T. Piatkowski, Dana L.

Defining the Sphagnum Core Microbiome across the North American Continent Reveals a Central Role for Diazotrophic Methanotrophs in the Nitrogen and Carbon Cycles of Boreal Peatland Ecosystems

• DOI: 10.1128/mbio.03714-21
• 发表时间: 2022-02-22
• 期刊: mBio
• 影响因子: 6.4
• 作者: Kolton M;Weston DJ;Mayali X;Weber PK;McFarlane KJ;Pett-Ridge J;Somoza MM;Lietard J;Glass JB;Lilleskov EA;Shaw AJ;Tringe S;Hanson PJ;Kostka JE
• 通讯作者: Kostka JE

Climate drivers alter nitrogen availability in surface peat and decouple N2 fixation from CH4 oxidation in the Sphagnum moss microbiome

• DOI: 10.1111/gcb.16651
• 发表时间: 2023-03
• 期刊: Global Change Biology
• 影响因子: 11.6
• 作者: Caitlin Petro;Alyssa A. Carrell;R. Wilson;Katherine Duchesneau;Sekou Noble-Kuchera;T. Song;C. Iversen;J. Childs;Geoffrey W. Schwaner;J. Chanton;R. Norby;P. Hanson;J. Glass;D. Weston;J. Kostka

Expansion of the global RNA virome reveals diverse clades of bacteriophages

• DOI: 10.1016/j.cell.2022.08.023
• 发表时间: 2022-10-13
• 期刊: CELL
• 影响因子: 64.5
• 作者: Neri, Uri;Wolf, Yuri I.;Gophna, Uri
• 通讯作者: Gophna, Uri

Nitrogen and phosphorus cycling in an ombrotrophic peatland: a benchmark for assessing change

营养泥炭地的氮磷循环：评估变化的基准

• DOI: 10.1007/s11104-021-05065-x
• 发表时间: 2021
• 期刊: Plant and Soil
• 影响因子: 4.9
• 作者: Salmon, Verity G.;Brice, Deanne J.;Bridgham, Scott;Childs, Joanne;Graham, Jake;Griffiths, Natalie A.;Hofmockel, Kirsten;Iversen, Colleen M.;Jicha, Terri M.;Kolka, Randy K.
• 通讯作者: Kolka, Randy K.