Global change processes in peatlands: A study of the microbiology and biogeochemistry of reactive nitrogen oxides

项目亮点：-一项新的研究，旨在揭示英国泥炭地网络中活性氮氧化物(NOY)排放的重要性。了解泥炭地污染对人类和更广泛的环境福祉是重要的。-多机构监督伙伴关系，与最先进的仪器设备和在资助的泥炭地研究项目中更广泛合作的机会相联系。-实验室和现场经验的结合，获得从分子技术到现场微量气体测量的各种技能概述：英国的泥炭地占土地覆盖面积的9.5%1，目前正在经历快速变化，以应对环境刺激，如人类活动导致的大气氮(N)沉积增加。这些生态系统发挥着过多的功能，其中最关键的莫过于充当大型有机物质储藏库(OM)。研究表明，氮沉积可以将这些有机质储存转化为温室气体(CO2、CH4)。2然而，到目前为止，人们对增强的氮沉积如何改变释放活性氮氧化物(NOY=NO、NO2、HONO)的N循环过程的关注要少得多。活性氮氧化物的研究很少，特别是在氮沉积增加的情况下，泥炭地可能以很高的速率排放活性氮氧化物。NOY气体被归类为空气污染物，会导致人类呼吸困难，还可以催化反应，导致地面臭氧形成和植被破坏。在更大的尺度上具有全球意义，因为它们控制着大气的氧化能力、温室气体的寿命以及直接和间接影响气候的二次气溶胶形成的速度。虽然NOY是已知的硝化和反硝化产物，但最近发现的一种涉及铁的过程(Feammox)对这些生态系统中NOY的产生和排放极其重要。Feammox是一种微生物过程，通常发生在泥炭地等饱和土壤的缺氧条件下，在没有氧气的情况下，铁氧化物可以作为电子受体，在影响N反应的过程中发挥关键作用。有人认为，厌氧土壤3-6中高达7%的氮损失可能是由Femmanox介导的，但由于这方面的研究很少，估计值很不确定。因此，迫切需要(I)确定英国泥炭地产生NOY的内在能力，(Ii)探索N沉积对这些生态系统中N循环速率的影响，以及(Iii)区分N在泥炭地转化的机制，特别注意微生物-铁的中介过程。

Project Highlights: - New research to unravel the significance of reactive nitrogen oxide (NOy) emissions from a network of UK peatland sites. Understanding peatland NOy is important for human and wider environmental well-being. - A multi-institute supervisory partnership linking to state-of-the-art instrumentation and opportunities for wider collaboration in funded peatland research projects. - A blend of laboratory and field experience, accessing skills ranging from molecular techniques to in-situ trace gas measurement Overview:Peatlands in the UK account for 9.5% of land cover1 and are currently experiencing rapid modifications in response to environmental stimuli such as increased atmospheric nitrogen (N) deposition sourced from human activity. These ecosystems perform a plethora of functions, none more critical than acting as large reservoirs of organic matter (OM). Research has demonstrated that N-deposition may transform these OM stocks into sources of greenhouse gases (CO2, CH4).2 However, to date much less attention has been paid to how enhanced N deposition may also change N-cycling processes that release reactive nitrogen oxides (NOy = NO, NO2, HONO).Reactive nitrogen oxides are greatly understudied and may be emitted at high rates from peatlands, especially under increased N-deposition. NOy gases are categorized as air pollutants causing respiratory distress in humans and can also catalyse reactions that lead to ground level ozone formation and vegetation damage. At larger scales are globally significant as they control the oxidative capacity of the atmosphere, the lifetime of greenhouse gases, and the rate of secondary aerosol formation that directly and indirectly affects climate. While NOy are known products of nitrification and denitrification, a recently identified process involving iron (Feammox) has been suggested as being extremely important for the production and emission of NOy in these ecosystems. Feammox is a microbial process that generally occurs under anoxic conditions of saturated soils such as peatlands, where iron oxides can act as an electron acceptor and play a critical role influencing N reactions in the absence of oxygen. It is suggested that up to 7% loss of N from anaerobic soils3-6 may be mediated by Femmanox but estimates are highly uncertain due to the paucity if research in this area. Thus, there is a critical need to (i) determine the intrinsic ability of UK peatlands to produce NOy, (ii) explore the influence of N-deposition on N-cycle rates in these ecosystems, and (iii) differentiate the mechanisms by which N is transformed in peatlands, paying particular attention to microbe-iron mediate processes.