Transport, anoxia and end-product accumulation control carbon dioxide and methane production and release in peat soils
Transport, anoxia and end-product accumulation control carbon dioxide and methane production and release in peat soils
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运输、缺氧和最终产物积累控制泥炭土中二氧化碳和甲烷的产生和释放
DOI：
10.1007/s10533-017-0328-7
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发表时间：
--
期刊：
影响因子：
4
通讯作者：
Knorr KH
中科院分区：
文献类型：
--
作者：
Bonaiuti S;Blodau C;Knorr KH
在水饱和的泥炭土中，由于缺乏溶质和气体的运输，厌氧呼吸和甲烷生成被发现会减慢，并积累代谢终产物，即溶解无机碳（DIC）和甲烷（CH 4）。到目前为止，还没有很好地理解溶质和气体的运输如何控制这种影响。我们在20 °C下用均质化的湿营养泥炭进行了300天的柱实验。我们具体评估了作为控制的扩散通量、向下的平流水通量、通过导管气体输送和扩散供氧来加强沸腾对控制厌氧分解速率和碳（C）周转的影响。为了模拟平流通量，在汽提溶解的气体之后，水和溶质向下再循环通过柱。我们分析了DIC和CH 4浓度，生产率和通量，充气孔隙度，氧气剖面（O2）和微生物碳生物量随时间的变化。DIC停留时间，从而作为代理，以表征运输。随着终产物DIC和CH 4的积累，厌氧呼吸和甲烷生成速率逐渐减慢，并在150天后开始。这种减缓伴随着微生物生物量C随深度的分布减少。厌氧DIC和CH 4生产率最快接近地下水位和急剧放缓的深度。DIC和CH 4在整个柱中的均质泥炭物质中的积累使分解常数从近地表的10− 5降低到剖面中的10− 9年− 1。平流水运输扩大了区域的活性甲烷相比，扩散系统;实验增强沸腾有很小或没有影响，以及严格缺氧条件。DIC停留时间呈负相关，无氧呼吸，这表明这个参数是一个预测泥炭地的泥炭厌氧分解。总的来说，这项研究表明，埋葬泥炭和积累的代谢最终产品有效地减缓分解，这种效果需要考虑解释泥炭积累和泥炭矿化率的响应环境条件的变化。
Anaerobic respiration and methanogenesis have been found to slow-down in water saturated peat soils with accumulation of metabolic end-products, i.e. dissolved inorganic carbon (DIC) and methane (CH4), due to a lack of solute and gas transport. So far it is not well understood how solute and gas transport may control this effect. We conducted a column experiment with homogenized ombrotrophic peat over a period of 300 days at 20 °C. We specifically evaluated the effects of diffusive flux as control, downward advective water flux, intensified ebullition by conduit gas transport and diffusive oxygen supply on controlling anaerobic decomposition rates and carbon (C) turnover. To simulate advective flux, water and solutes were recirculated downward through the column after stripping of dissolved gases. We analyzed DIC and CH4concentrations, production rates and fluxes, gas filled porosity, oxygen profiles (O2) and microbial C biomass over time. DIC residence time thereby served as proxy to characterize transport. A slowdown of anaerobic respiration and methanogenesis evolved with the accumulation of the end-products DIC and CH4and set in after 150 days. This slow-down was accompanied by a decrease in the distribution of microbial biomass C with depths. Anaerobic DIC and CH4production rates were fastest close to the water table and sharply slowed with depth. Accumulation of DIC and CH4in the homogeneous peat material throughout the column decreased decomposition constants from about 10−5near the surface to 10−9year−1deeper in the profile. Advective water transport extended the zone of active methanogenesis compared to a diffusive system; experimental enhancement of ebullition had little or no effect as well as strictly anoxic conditions. DIC residence time was negatively correlated to anaerobic respiration suggesting this parameter to be a predictor of anaerobic peat decomposition in peatlands. Overall, this study suggests that burial of peat and accumulation of metabolic end-products effectively slows decomposition and that this effect needs to be considered to explain peat accumulation and the response of peat mineralization rates to changes in environmental conditions.
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通讯作者：
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影响因子：
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DOI：
10.1029/2008gm000811
发表时间：
2013
期刊：
Geophysical monograph
影响因子：
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通讯作者：
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作者：
Basiliko, Nathan;Moore, Tim R.;Bubier, Jill L.
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