Microbial oxidation of lithospheric organic carbon in rapidly eroding tropical mountain soils
Microbial oxidation of lithospheric organic carbon in rapidly eroding tropical mountain soils
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DOI：
10.1126/science.aao6463
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发表时间：
2018-04-13
期刊：
影响因子：
56.9
通讯作者：
Galy, Valier V.
中科院分区：
文献类型：
--
作者：
Hemingway, Jordon D.;Hilton, Robert G.;Galy, Valier V.
岩石圈有机碳（“成岩”; OCpetro）在山脉的剥露和随后的侵蚀过程中被氧化。在地质时间尺度上，这一过程是向大气中排放二氧化碳（CO2）的重要来源，但控制山地景观氧化率的机制受到的限制很小。我们证明，平均而言，67 +/- 11%的OCpetro最初存在于从热带，快速侵蚀的台湾中央山脉挖出的基岩中，在土壤中被氧化，导致每年每平方公里6.1至18.6公吨碳的二氧化碳排放量。在土壤形成过程中的散装OC和脂质生物标志物的分子和同位素演化表明，OCpetro矿化是微生物介导的。山地土壤的快速氧化驱动CO2排放通量随侵蚀速率的增加而增加，从而抵消了硅酸盐风化和生物圈OC埋藏引起的CO2下降。
Lithospheric organic carbon ("petrogenic"; OCpetro) is oxidized during exhumation and subsequent erosion of mountain ranges. This process is a considerable source of carbon dioxide (CO2) to the atmosphere over geologic time scales, but the mechanisms that govern oxidation rates in mountain landscapes are poorly constrained. We demonstrate that, on average, 67 +/- 11% of the OCpetro initially present in bedrock exhumed from the tropical, rapidly eroding Central Range of Taiwan is oxidized in soils, leading to CO2 emissions of 6.1 to 18.6 metric tons of carbon per square kilometer per year. The molecular and isotopic evolution of bulk OC and lipid biomarkers during soil formation reveals that OCpetro remineralization is microbially mediated. Rapid oxidation in mountain soils drives CO2 emission fluxes that increase with erosion rate, thereby counteracting CO2 drawdown by silicate weathering and biospheric OC burial.