Impact of the drought in England on carbon dioxide fluxes from lowland peatland in the East Anglian fens across a land use gradient

英格兰干旱对东安格利亚沼泽低地泥炭地二氧化碳通量跨土地利用梯度的影响

• 批准号: NE/K001590/1
• 负责人: Heiko Balzter
• 金额: $ 6.33万
• 依托单位: University of Leicester
• 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%2FK001590%2F1
• 关键词: Impact; drought; England; carbon; dioxide

Large parts of South-Eastern and Eastern England have recently been declared to be in a state of drought. On 20 February 2012, Environment Secretary Caroline Spelman declared a state of drought, citing concerns about the drinking water supply, diminishing ground water resources and possible water use restrictions. The drought has led to visible impacts on East Anglian lowland peat soils in the fens, where road surfaces have started to crack due to peat contraction. The drought creates an unexpected scientific opportunity to measure its impacts on greenhouse gas emissions from fenland ecosystems. This grant will establish a measurement station on an agricultural field near Wicken Fen, Cambridgeshire, to measure greenhouse gas fluxes.We will test is whether the drought conditions lead to enhanced carbon dioxide emissions from lowland peatland, and whether wetland restoration increases resilience against drought in comparison to agricultural land.Besides the direct impacts of the drought on infrastructure and water supply, there is an urgent need to study the impacts on the carbon cycle and radiative forcing. Predictions by climate models generally suggest an increasing frequency of previously rare extreme events. As a result of the increase of global average temperature it is thus reasonable to expect that prolonged dry conditions like those currently experienced this spring in England could happen more often. It is imperative to start recording direct measurements of carbon fluxes during drought conditions to have quantitative evidence of the carbon impact of drought conditions.Lowland peat soils in England occupy 958 km2, store large amounts of carbon and are subject to very high levels of land use pressure because of their high agricultural productivity. To date, most measurements of CO2 and other greenhouse gas (GHG) fluxes from UK peatlands were collected in upland blanket bogs. There are doubts whether the blanket bog GHG fluxes can simply be assumed to apply to lowland fenland. In England, nearly all fenland has been drained and cultivated for intensive agriculture. In the fens of East Anglia, this has resulted in rates of peat loss of about 1 cm yr-1.Natural England (2010) were the first to provide initial GHG flux emission factors for English peat soils. According to this report, degraded English peats alone are thought to emit around 3 Mt CO2-eq yr-1. Recent peatland studies for DEFRA and JNCC have highlighted the high degree of uncertainty in GHG flux estimates for lowland peats and in particular for fens.At the Wicken Fen National Nature Reserve near Cambridge, the Centre for Ecology and Hydrology (CEH) and the University of Leicester (UoL) have installed two eddy covariance towers. The measurements of CO2 fluxes at the natural fenland site in Sedge Fen (operated by CEH) and the wetland regeneration site at Bakers Fen (operated by UoL) are providing important time-series data that allow inferences on the carbon balance. These two flux towers are the only measurement stations in lowland peatland in the UK.The gap in current measurements is in the agriculturally used fenland area.The purpose of this NERC urgency grant is to fund technical and research staff time to collect eddy covariance CO2 measurements over agriculturally used fenland in the growing season of 2012 and beyond to record the impacts of the current drought and the recovery of CO2 fluxes to a more usual state.

英格兰东南部和东部的大部分地区最近被宣布处于干旱状态。2012年2月20日，环境部长卡罗琳·斯佩尔曼（Caroline Spelman）宣布进入干旱状态，理由是对饮用水供应、地下水资源减少和可能的用水限制感到担忧。干旱对东安格利亚沼泽低地泥炭土造成了明显的影响，由于泥炭收缩，路面开始开裂。干旱创造了一个意想不到的科学机会来测量它对芬兰生态系统温室气体排放的影响。这笔拨款将在剑桥郡威肯芬附近的一块农田上建立一个测量站，以测量温室气体通量。我们将测试干旱条件是否会导致低地泥炭地的二氧化碳排放增加，以及与农业用地相比，湿地恢复是否会增强对干旱的抵御能力。干旱除了对基础设施和供水的直接影响外，还迫切需要研究其对碳循环和辐射强迫的影响。气候模型的预测通常表明，以前罕见的极端事件的频率正在增加。由于全球平均气温的上升，我们有理由预计，像今年春天在英国经历的那样，长期干旱的情况可能会更频繁地发生。必须开始记录干旱条件下碳通量的直接测量，以获得干旱条件对碳影响的定量证据。英格兰的低地泥炭土占地958平方公里，储存了大量的碳，由于其高农业生产力，土地利用压力非常大。迄今为止，大多数来自英国泥炭地的二氧化碳和其他温室气体（GHG）通量的测量都是在高地地毯式沼泽中收集的。有人怀疑毯状沼泽温室气体通量是否可以简单地假定适用于低地沼泽。在英格兰，几乎所有的芬兰土地都被抽干，用于集约化农业。在东安格利亚沼泽地区，这导致泥炭的损失率约为每年1厘米。Natural England（2010）首次提供了英国泥炭土的初始温室气体通量排放因子。根据这份报告，仅退化的英国泥炭就被认为每年排放约300万吨二氧化碳当量。最近为DEFRA和JNCC进行的泥炭地研究强调了对低地泥炭地，特别是沼泽的温室气体通量估计的高度不确定性。在剑桥附近的威肯芬国家自然保护区，生态和水文中心（CEH）和莱斯特大学（UoL）安装了两个涡流相关塔。在Sedge Fen的天然沼泽地（由CEH运营）和baker Fen的湿地再生场地（由UoL运营）的二氧化碳通量测量提供了重要的时间序列数据，可以推断碳平衡。这两个通量塔是英国低地泥炭地仅有的测量站。目前测量的差距是在农业用地的芬兰地区。这项紧急拨款的目的是为技术和研究人员提供资金，以便在2012年及以后的生长季节收集农业用芬兰地区的涡旋相关二氧化碳测量数据，以记录当前干旱的影响，并将二氧化碳通量恢复到更正常的状态。

项目成果

FENFLUX: The short-term climate response of carbon dioxide, methane and water fluxes from a regenerating fen in East Anglia, UK

FENFLUX：英国东安格利亚沼泽再生过程中二氧化碳、甲烷和水通量的短期气候响应

• 作者: Gong Pan (Author)

Net ecosystem carbon dioxide exchange at semi-natural and regenerating temperate fens

半自然和再生温带沼泽生态系统二氧化碳净交换

• 作者: Ross Morrison (Author)