Linking Microbial Physiology with Carbon Transformations in Peatlands Under Land Use Change

将微生物生理学与土地利用变化下泥炭地的碳转化联系起来

• 批准号: 2445868
• 金额: --
• 依托单位: University of Aberdeen
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2445868
• 关键词: Linking; Microbial; Physiology; Carbon; Transformations

Significant amount of carbon is stored in soils, particularly in peatlands. Increasing food and energy needs have led to intensive land use practices that deplete soil organic carbon (SOC) stores. In Scotland, drainage for agriculture and commercial forestry in its vast swathes of peatlands has caused their degradation with significant loss of carbon. Their recent restoration has led to the return of SOC sequestration, and associated climate benefits, but the underlying carbon cycling mechanisms have not been clearly understood. This mechanistic understanding is required to better predict and manage soil processes to maintain or even enhance SOC storage in peatlands while economising land-use.Microorganisms are critical in this regard because their growth and activity largely control the fate of recent plant carbon inputs, as well as the stability of assimilated microbial carbon. The balance between the rate of microbial decomposition and stabilisation of organic carbon in soil can shift under altered environmental conditions. In peatlands, water-logged conditions, anaerobiosis and acidity limit microbial growth and decomposition that consequently causes preservation of organic carbon. Peatland degradation through drainage removes the factors causing organic carbon preservation thus leading to SOC loss through microbial decomposition. Restorative approaches aim at reversing these effects thereby limiting the loss of SOC; however, the exact hydrological, chemical and biotic mechanisms and their inter-dependencies are poorly understood.This project aims at understanding the effects of peatland degradation and subsequent restoration on microbial physiological processes and their consequences on soil carbon transformations. Project will rigorously test the hypotheses that microbial growth, activity and decomposition is limited by acidity and anaerobiosis in peatlands; and that peatland degradation causes increased microbial growth and consequently decomposition of peat organic matter. We will have access to multiple peatland sites under various land use types across Scotland to test the hypotheses. The goal is to assess microbial carbon cycling functions like growth rate, carbon use efficiency, resource breakdown and uptake, maintenance and stress tolerance. These community traits will be quantified using a combination of stable isotope tracing and shot-gun metagenomics, and their fingerprints in driving changes in SOC will be assessed using chemical molecular tools like FTIR.Using stable isotope tracers, we will measure microbial incorporation of carbon into biomass and loss through respiration to quantify community-level traits like carbon use efficiency, growth rate and specific respiration across land use types. Analytical facilities for gas, solid, soil solution and compound-specific 13C isotope ratio mass spectrometry (IRMS) including cavity ring-down spectrometry (CRDS) at University of Aberdeen (UoA) and James Hutton Institute (JHI) are unique and training will be provided by the supervisory team. Whole genome shot-gun metagenomics will be used to investigate functions of peatland microbial communities under different land use. The goal here will be to extract physiological traits of microbes that are dominant in soils under different land use.The Centre for Genome Enabled Biology and Medicine (www.abdn.ac.uk/genomics) at UoA houses DNA sequencing platforms like Illumina NextSeq500 and Oxford Nanopore GridION which will be available to the project including training in molecular methods and bioinformatics. Chemical analysis of the extant organic matter will be used to characterise peatland organic matter at the molecular level using FTIR. Once we are able to form a link between microbial traits and carbon cycling processes, we will be able to use the combined knowledge to ascertain the efficacy of restorative practices in changing microbial physiology aimed at regaining and sequestering carbon in peatlands.

大量的碳储存在土壤中，尤其是泥炭地。不断增加的粮食和能源需求导致了土地集约利用做法，耗尽了土壤有机碳(SOC)储存。在苏格兰，大片泥炭地的农业和商业林业排水导致了它们的退化，碳的大量流失。它们最近的恢复导致了SOC固存的回归，以及相关的气候好处，但潜在的碳循环机制尚未被清楚地理解。在节约土地利用的同时，需要更好地预测和管理土壤过程，以维持甚至增强泥炭地的有机碳储存。微生物在这方面是至关重要的，因为它们的生长和活动在很大程度上控制着最近植物碳输入的命运，以及同化微生物碳的稳定性。在改变的环境条件下，土壤中微生物分解速率和有机碳稳定化之间的平衡会发生变化。在泥炭地，淹水条件、厌氧和酸度限制了微生物的生长和分解，从而导致有机碳的保存。通过排水的泥炭地退化消除了导致有机碳保存的因素，从而通过微生物分解导致有机碳的损失。恢复性方法旨在逆转这些影响，从而限制有机碳的损失；然而，确切的水文、化学和生物机制及其相互依赖关系尚不清楚。本项目旨在了解泥炭地退化和随后的恢复对微生物生理过程的影响及其对土壤碳转化的影响。该项目将严格检验以下假设，即微生物的生长、活动和分解受到泥炭地酸度和厌氧性的限制；泥炭地退化导致微生物生长增加，从而分解泥炭有机物质。我们将访问苏格兰各地不同土地利用类型下的多个泥炭地，以验证假设。目标是评估微生物的碳循环功能，如生长速度、碳利用效率、资源分解和吸收、维持和抗逆性。这些群落特征将使用稳定同位素示踪和枪炮元基因组学相结合的方法进行量化，并将使用FTIR等化学分子工具评估其在驱动SOC变化方面的指纹。使用稳定同位素示踪剂，我们将测量微生物将碳并入生物量和通过呼吸作用损失，以量化不同土地利用类型的群落特征，如碳利用效率、生长速度和比呼吸作用。阿伯丁大学(UoA)和詹姆斯·赫顿研究所(JHI)的气体、固体、土壤溶液和特定于化合物的13C同位素比质谱仪(IRMS)的分析设施是独一无二的，监督小组将提供培训。全基因组弹枪元基因组学将用于研究泥炭地微生物群落在不同土地利用方式下的功能。这里的目标是提取在不同土地利用下土壤中占主导地位的微生物的生理特征。加州大学基因组使能生物和医学中心(www.abdn.ac.uk/genology)拥有Illumina NextSeq500和牛津纳米孔网格等DNA测序平台，这些平台将用于该项目，包括分子方法和生物信息学方面的培训。现有有机质的化学分析将被用来利用FTIR在分子水平上表征泥炭地有机质。一旦我们能够在微生物特征和碳循环过程之间建立联系，我们就能够利用组合的知识来确定恢复性做法在改变旨在恢复和隔离泥炭地碳的微生物生理方面的有效性。