Role of fungal communities in carbon and nutrient cycling in forest soils under elevated atmospheric CO2 concentrations

大气二氧化碳浓度升高下森林土壤中真菌群落在碳和养分循环中的作用

• 批准号: 2874480
• 金额: --
• 依托单位: University of Birmingham
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2874480
• 关键词: Role; fungal; communities; carbon; nutrient

Fungal communities are known to play influential roles in woodland ecosystems, yet much remains unknown about their diversity, functioning, and likely responses to environmental change. This project aims to address some of these knowledge gaps by investigating mycorrhizal fungal communities at the Birmingham Institute of Forest Research Free Air Carbon Dioxide Enrichment site (BIFoR FACE). The only facility of its kind in the northern hemisphere, BIFoR FACE is a large-scale experiment subjecting patches of mature temperate woodland to elevated CO2 levels (approx. 550 ppm) with the aim of illuminating likely effects of future increases in atmospheric CO2 on this kind of ecosystem. Though elevated CO2 levels are expected initially to enhance tree growth, it is predicted that this growth enhancement may be relatively short-lived as the availability of soil nutrients - in the northern hemisphere, primarily nitrogen - could become limiting in the longer term. A fuller appraisal of this "progressive nitrogen limitation" (PNL) hypothesis demands consideration of fungal communities as ectomycorrhizal fungi in particular can supply significant quantities of otherwise inaccessible nitrogen to their plant hosts, although the extent to which this occurs varies between different species and environmental conditions. One possible scenario with some empirical support is that under elevated CO2 trees will invest more carbon in their mycorrhizal symbionts and receive more nitrogen from these fungi in return, alleviating PNL. Conversely, experimental evidence from boreal forest ecosystems has suggested that greater allocation of carbon from trees to mycorrhizal fungi can lead to increased amounts of nitrogen being locked up in proliferating mycorrhizal biomass, rather than being transferred to tree hosts, thus exacerbating PNL. This project will use molecular techniques firstly to characterize the mycorrhizal fungal communities present in elevated- and ambient-CO2 plots at the BIFoR FACE site, determining whether differences in community composition are apparent between the two conditions. This will then form the basis for investigating possible changes in mycorrhizal nutrient acquisition and transfer under elevated CO2, whether through community compositional shifts or altered functioning under different conditions, thus connecting mycorrhizal fungal responses to elevated CO2 with their wider effects in terms of nutrient cycling and tree growth.

众所周知，真菌群落在林地生态系统中扮演着影响力的角色，但对它们的多样性，功能以及可能对环境变化的反应仍然不知道。该项目的目的是通过调查伯明翰森林研究所免费二氧化碳富集地点（BiFor Face）的菌根真菌群落来解决其中一些知识差距。双子脸是北半球同类唯一的设施，是一个大规模的实验，对成熟的温带林地的斑块达到升高的二氧化碳水平（约550 ppm），其目的是阐明了这一可能的可能对未来大气二氧化碳的可能增加一种生态系统。尽管最初预计二氧化碳水平升高可以增强树木的生长，但可以预测，这种增长可能相对短暂，因为在北半球（主要是氮气）的土壤养分的可用性可能会在长期内限制。对这种“渐进的氮限制”（PNL）假设的更全面评估要求将真菌群落视为外生菌骨真菌，尤其是可以为其植物宿主提供大量的其他氮，尽管这在不同的物种和环境之间发生了不同的程度状况。有一些经验支持的一种可能情况是，高架二氧化碳将在其菌根共生体中投入更多的碳，并从这些真菌中获得更多的氮，从而减轻了PNL。相反，来自北方森林生态系统的实验证据表明，从树上到菌根真菌的碳分配更大，可以导致增加氮量增加，以增加菌根生物量的增殖，而不是被转移到树宿主中，从而恶化PNL。该项目将首先使用分子技术来表征在双子型面部位点升高和环境-CO2图中存在的菌根真菌群落，从而确定两个条件之间社区组成的差异是否显而易见。然后，这将构成调查菌根营养物质获取和转移二氧化碳的转移的可能变化的基础树木生长。