Short period of oxygenation releases latch on peat decomposition
Short period of oxygenation releases latch on peat decomposition
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DOI：
10.1016/j.scitotenv.2014.02.030
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发表时间：
2014-05-15
影响因子：
9.8
通讯作者：
Hefting, Mariet M.
中科院分区：
文献类型：
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作者：
Brouns, Karlijn;Verhoeven, Jos T. A.;Hefting, Mariet M.
由于气候变化，预计欧洲西北部未来将更经常发生极端夏季干旱。这些干旱可能会加速排水泥炭区的泥炭氧化速度，对土壤沉降、温室气体排放和水质产生影响。本研究旨在提供更多的洞察力，在氧化的深层泥炭层，以前没有暴露在空气中，所谓的二次decomposition.We孵化两种类型的泥炭（富营养和贫营养），从永久缺氧泥炭层自然保护区和农业泥炭草甸采样。泥炭样品在缺氧条件下孵育13周，但暴露于空气中1至8周。CO2和CH 4的产生被量化为分解的代理;可溶性营养物质和酚类化合物的浓度也measured. Results表明，充氧导致分解率急剧增加，由较高的碳损失率期间和之后的充氧相比，非充氧样品。富营养泥炭的碳损失率（农业区：352%，自然保护区：182%）比贫营养泥炭（83%和159%）增加更多。大多数泥炭样品的调查表明，较高的后氧化CO2和/或CH 4生产相比，缺氧预氧化期间。这表明氧合刺激分解，即使在缺氧条件已经恢复。相反的酶闩锁理论，没有氧化的影响，对可溶性或缩合酚类化合物的浓度进行检测。可溶性营养盐浓度没有改变，由于氧化。值得注意的是富营养化泥炭中黄铁矿矿化和相关酸化的发生。因此，应避免因气候变化等原因造成的夏季低水位，以限制异常高的分解率和相关问题，如沉降率增加、温室气体排放、硫酸盐释放和酸化。(C)© 2014 Elsevier B. V.保留所有权利。
Extreme summer droughts are expected to occur more often in the future in NW Europe due to climate change. These droughts might accelerate the rate of peat oxidation in drained peat areas, with impacts on soil subsidence, GHG emission and water quality. This study aimed at providing more insight in the oxidation of deep peat layers that had not previously been exposed to air, the so-called secondary decomposition.We incubated two types of peat (eutrophic and oligotrophic), sampled from permanently anoxic peat layers from nature reserves and agricultural peat meadows. Peat samples were incubated for thirteen weeks under anoxic conditions, but were exposed to air for one to eight weeks. The production of CO2 and CH4 was quantified as a proxy for decomposition; concentrations of soluble nutrients and phenolic compounds were also measured.The results showed that oxygenation led to a steep increase in the rate of decomposition, indicated by higher carbon loss rates during and after oxygenation compared to non-oxygenated samples. Carbon loss rates increased more for eutrophic peat (agricultural area: 352%, nature reserve: 182%) than for oligotrophic peat (83% and 159% respectively). Most peat samples investigated showed higher post-oxygenation CO2 and/or CH4 production compared to the anoxic pre-oxygenation period. This indicates that oxygenation stimulates decomposition, even after anoxic conditions have returned. Contrary to the enzymic latch theory, no effects of oxygenation on the concentrations of soluble or condensed phenolic compounds were detected. Soluble nutrient concentrations did not change due to oxygenation either. Noteworthy is the occurrence of pyrite mineralization and associated acidification in eutrophic peat. Thus, low summer water levels, for example due to climate change, should be avoided in order to limit exceptionally high decomposition rates and associated problems such as increasing subsidence rates, greenhouse gas emission, sulfate release and acidification. (C) 2014 Elsevier B.V. All rights reserved.