The organic carbon dynamics of a moorland catchment in N. W. England
The organic carbon dynamics of a moorland catchment in N. W. England
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DOI：
10.1007/s10533-007-9117-z
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发表时间：
2007-05
期刊：
影响因子：
4
通讯作者：
E. Tipping;E. J. Smith;C. Bryant;J. Adamson
中科院分区：
文献类型：
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作者：
E. Tipping;E. J. Smith;C. Bryant;J. Adamson
在北方英格兰的Doe House Gill集水区对碳循环进行了量化，该集水区为高起伏的高沼地，富含有机物的土壤（薄土和灰壤）厚度为10-25 cm。土壤碳库为8,300 g/m-2，主要是由于腐殖酸和较老的胡敏素。如果假设处于稳定状态，并且只有一个土壤碳库，则整个土壤的平均14 C含量（93%现代）得出的平均碳停留时间为800年，尽管在所研究的四个样本中，这一时间从300年到1，600年不等。2002-2003年，溶解有机碳和颗粒有机碳（DOC，POC）的溪流水通量分别为2.5和0.4 g m−2 a−1，低于英国其他一些高地溪流的数值。利用碳库、碳通量和碳同位素数据，在稳态假设下，对DyDOC模型进行了标定，该模型模拟了土壤碳循环，包括DOC的生成和迁移。根据DyDOC，垃圾池（约。100 gC m−2）迅速转化，大部分（>90%）的凋落物碳迅速矿化。计算出土壤仅增加16 gC m−2 a−1，并损失相同的量，约80%为CO2，20%为DOC。从107.5%的DO 14 C含量现代（由于“炸弹碳”）的模型可以通过假设所有DOC直接来自凋落物进行校准，但DOC更可能是一种混合物，来自一个以上的土壤C库。表现出的季节性变化的溪流水DOC浓度（最大值在9月，最小值在1月）主要是由于降雨量和蒸散量的变化，而不是在代谢生产率的“潜在DOC”。该模型预测，Q10为2，土壤有机碳总库将减少约5%，如果受到200年的变暖。DyDOC预测较高的DOC通量响应于增加凋落物输入或变暖，并可以模拟DOC通量的变化，由于土壤固体吸附的变化，可能会发生由于酸化及其逆转。
The carbon cycle was quantified in the catchment of Doe House Gill, which drains high-relief moorland, with thin organic-rich soils (leptosols and podzols) 10–25 cm deep, in northern England. The soil C pool of 8,300 g m-2 is due mainly to humic acid and older humin. If steady state is assumed, and a single soil C pool, the average 14C content of the whole soil (93% modern) yields a mean carbon residence time of 800 years, although this varied from 300 to 1,600 years in the four samples studied. Stream water fluxes of dissolved and particulate organic carbon (DOC, POC) were 2.5 and 0.4 g m−2 a−1 respectively in 2002–2003, lower than values for some other upland streams in the UK. The C pool, flux, and isotope data were used, with the assumption of steady state, to calibrate DyDOC, a model that simulates the soil carbon cycle, including the generation and transport of DOC. According to DyDOC, the litter pool (ca. 100 gC m−2) turns over quickly, and most (>90%) of the litter carbon is rapidly mineralised. The soil is calculated to gain only 16 gC m−2 a−1, and to lose the same amount, about 80% as CO2 and 20% as DOC. From the DO14C content of 107.5% modern (due to “bomb carbon”) the model could be calibrated by assuming all DOC to come directly from litter, but DOC is more likely a mixture, derived from more than one soil C pool. The seasonal variability exhibited by stream water DOC concentration (maximum in September, minimum in January) is attributed mainly to variations in rainfall and evapotranspiration, rather than in the metabolic production rate of “potential DOC”. The model predicts that, for a Q10 of 2, the total soil organic C pool would decrease by about 5% if subjected to warming over 200 years. DyDOC predicts higher DOC fluxes in response to increased litter inputs or warming, and can simulate changes in DOC flux due to variations in sorption to soil solids, that might occur due to acidification and its reversal.