The Boreal Nitrogen Gap: Size, fate and impacts of nitrogen fixation in Fennoscandia forest ecosystems

北方氮缺口：Fennoscandia 森林生态系统固氮的规模、命运和影响

• 批准号: NE/I027037/1
• 负责人: Nicholas Ostle
• 金额: $ 8.4万
• 依托单位: NERC CEH (Up to 30.11.2019)
• 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%2FI027037%2F1
• 关键词: Boreal; Nitrogen; Gap; Size; fate

Nitrogen is a primary limiting nutrient in high boreal and subarctic forest ecosystems, unfortunately, our understanding of fundamental N cycling processes in these oligotrophic environs remains limited which in turn hinders our ability to effectively predict ecosystem carbon (C) turnover and greenhouse gas emissions. Over the past 10 years we have elucidated a major N input in high boreal and subarctic ecosystems (1, 2), specifically we described the occurrence of an association between cyanobacteria and the ubiquitous and dominant feathermosses Pleurozium schreberi and Hylocomium splendens (3, 4). These two mosses act as the primary sources of biologically fixed N in subarctic and boreal forest systems and are also important in Arctic alpine tundra ecosystems (5). Although we have developed a clear picture of the quantity of N fixed by this association (6), our understanding of the pathway for N release into the ecosystems from the feathermosses remains greatly incomplete. A thorough understanding of these pathways will lead to a better understanding of C cycling processes at high latitudes and benefit a range of researchers from botanists, to ecologists, to ecosystem modellers.In this proposal we put forth several compelling hypotheses to further our understanding of fundamental processes in the N cycle of boreal Scots pine ecosystems and advance our general knowledge of the ecology of the feathermoss-cyanobacterial association in boreal forests of northern Sweden. To date most of our understanding of this association has surrounded field studies regarding the ecology of the feathermosses, little effort has been made to link the association to the belowground nutrient cycles and microbial community. Studies have been designed to address the following objectives: The four primary objectives of this proposed research are therefore to: (1) Assess the relationship between feathermoss N fixation and site productivity along natural fertility gradients and N deposition gradients in northern Fennoscandia; (2) Determine the portion of fixed N that remains in an organic form in moss detritus and the role of disturbance in liberating this N; (3) Evaluate the role of mycorrhizas in the transfer of N (amino acid and peptide N) from feather mosses to plants; (4) Evaluate the relationship between fixed N and forest floor CO2, CH4, and N2O fluxes across N enrichment gradients (i.e. N deposition gradient and fire-chronosequence). Experiments will be conducted on established field sites in northern Sweden including a fire chronosequence to address change in N turnover with natural forest succession; a total of five natural fertility gradients to assess the influence of variable N and P limitation on N fixation, turnover and greenhouse gas emissions; and an anthropogenic N deposition gradient from southern to northern Sweden along which we will assess the influence of increased N deposition on N fixation, turnover and loss. These findings will have significant implications for those studying ecosystem processes at high latitudes including N fixation, N turnover, C fixation, and greenhouse gas emissions. It is our intent to work these results into existing biogeochemistry models that are designed to predict linked C and N dynamics as related to productivity and greenhouse gas emissions.Literature Cited1. T. H. DeLuca, O. Zackrisson, M.-C. Nilsson, A. Sellstedt, Nature 419, 917 (2002).2. O. Zackrisson, T. H. DeLuca, M.-C. Nilsson, A. Sellstedt, L. Berglund, Ecology 85, 3327 (2004).3. O. Zackrisson, T. H. DeLuca, F. Gentili, A. Sellstedt, A. Jäderlund, Oecologia In Press, (2009).4. F. Gentili, M. C. Nilsson, O. Zackrisson, T. H. DeLuca, A. Sellstedt, Journal of Experimental Botany 56, 3121 (2005).5. T. H. DeLuca, O. Zackrisson, Plant and Soil 294, 147 (2007).6 T. H. DeLuca, O. Zackrisson, M.-C. Nilsson, M. J. Gundale, Science 320, 1181 (2008).

不幸的是，氮是高北极和亚亚亚第亚森林生态系统中的主要限制养分，我们对这些寡养分环境中基本循环过程的理解仍然受到限制，反过来又阻碍了我们有效预测生态系统碳（C）碳（C）失误和温室气体发射的能力。在过去的十年中，我们阐明了高北极和亚北极生态系统中的主要N输入（1，2），具体来说，我们描述了蓝细菌与普遍存在和普遍存在的Feathermoss Pleurozium Schreberi和Hyllocomium splendens之间发生关联的发生（3，4）。这两个苔藓是亚北极和北方森林系统中生物固定n的主要来源，在北极高山苔原生态系统中也很重要（5）。尽管我们已经清楚地了解了该关联固定的N数量（6），但我们对n释放n释放到生态系统的途径的理解非常不完整。 A thorough understanding of these pathways will lead to a better understanding of C cycling processes at high latitudes and benefits a range of researchers from botanists, to ecologists, to ecosystem modellers.In this proposal we put forth several compelling hypotheses to further our understanding of fundamental processes in the N cycle of boreal Scots pine ecosystems and advance our general knowledge of the ecology of the feathermoss-cyanobacterial association in瑞典北部的北方森林。迄今为止，我们对这种关联的大部分理解都围绕着关于羽毛球生态的现场研究，几乎没有努力将关联与以下营养周期和微生物群落联系起来。研究旨在解决以下目标：因此，这项拟议的研究的四个主要目标是：（1）评估北部Fennoscandia沿天然生育率梯度与N型现场生产之间的关系； （2）确定在苔藓碎屑中保持有机形式的固定n部分，以及灾难在解放该n中的作用； （3）评估菌根在N（氨基酸和胡椒N）从羽毛苔藓转移到植物中的作用； （4）评估固定n与森林地板二氧化碳，CH4和N2O通量之间的关系（即n沉积梯度和火链钉）。实验将在北瑞典的既定现场进行实验，包括消防赛车，以解决N离职的变化，并取得天然林的成功；总共有五个天然生育率梯度来评估可变N和P限制对N固定，营业额和温室气体排放的影响；以及从瑞典南部到北部的人为N沉积梯度，我们将评估N沉积对N固定，周转和损失的影响。这些发现将对那些在高纬度上研究生态系统过程的人具有重大影响，包括n固定，N周转率，C固定和温室气体排放。我们的目的是将这些结果纳入现有的生物地球化学模型中，这些模型旨在预测与生产力和温室气体排放相关的链接的C和N动力学。引用1。 T. H. Deluca，O。Zackrisson，M.-C。 Nilsson，A。Sellstedt，Nature 419，917（2002）.2。 O. Zackrisson，T。H。Deluca，M.-C。 Nilsson，A。Sellstedt，L。Berglund，生态学85，3327（2004）.3。 O. Zackrisson，T。H。Deluca，F。Gentili，A。Sellstedt，A。Jäderlund，Oecologia，出版社（2009）.4。 F. Gentili，M。C。Nilsson，O。Zackrisson，T。H。Deluca，A。Sellstedt，实验植物学杂志56，3121（2005）.5。 T. H. Deluca，O。Zackrisson，植物和土壤294，147（2007）.6 T. H. Deluca，O。Zackrisson，M.-C。 Nilsson，M。J. Gundale，Science 320，1181（2008）。

项目成果

Can digital image classification be used as a standardised method for surveying peatland vegetation cover?

• DOI: 10.1016/j.ecolind.2015.11.035
• 发表时间: 2016-09-01
• 期刊: ECOLOGICAL INDICATORS
• 影响因子: 6.9
• 作者: Baxendale, Catherine L.;Ostle, Nick J.;Ward, Susan E.
• 通讯作者: Ward, Susan E.

Soil Methane Sink Capacity Response to a Long-Term Wildfire Chronosequence in Northern Sweden.

• DOI: 10.1371/journal.pone.0129892
• 发表时间: 2015
• 期刊: PloS one
• 影响因子: 3.7
• 作者: McNamara NP;Gregg R;Oakley S;Stott A;Rahman MT;Murrell JC;Wardle DA;Bardgett RD;Ostle NJ
• 通讯作者: Ostle NJ

Vascular plants promote ancient peatland carbon loss with climate warming.

随着气候变暖，维管束植物会促进泥炭地的碳流失。

• DOI: 10.1111/gcb.13213
• 发表时间: 2016-05
• 期刊: Global change biology
• 影响因子: 11.6
• 作者: Walker TN;Garnett MH;Ward SE;Oakley S;Bardgett RD;Ostle NJ
• 通讯作者: Ostle NJ

Warming effects on greenhouse gas fluxes in peatlands are modulated by vegetation composition.

• DOI: 10.1111/ele.12167
• 发表时间: 2013-10
• 期刊: Ecology letters
• 影响因子: 8.8
• 作者: Susan E. Ward;N. Ostle;S. Oakley;H. Quirk;P. Henrys;R. Bardgett

Boreal Forest Floor Greenhouse Gas Emissions Across a Pleurozium schreberi-Dominated, Wildfire-Disturbed Chronosequence

• DOI: 10.1007/s10021-019-00344-2
• 发表时间: 2019-02
• 期刊: Ecosystems
• 影响因子: 3.7
• 作者: Kelly E. Mason;S. Oakley;L. Street;M. Arróniz-Crespo;David L. Jones;T. DeLuca;N. Ostle