Latitude, Elevation, and Mean Annual Temperature Predict Peat Organic Matter Chemistry at a Global Scale
Latitude, Elevation, and Mean Annual Temperature Predict Peat Organic Matter Chemistry at a Global Scale
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纬度、海拔和年平均温度预测全球范围内的泥炭有机质化学
DOI：
10.1029/2021gb007057
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发表时间：
2022
影响因子：
5.2
通讯作者：
Benscoter, Brian W.
中科院分区：
文献类型：
--
作者：
Verbeke, Brittany A.;Lamit, Louis J.;Lilleskov, Erik A.;Hodgkins, Suzanne B.;Basiliko, Nathan;Kane, Evan S.;Andersen, Roxane;Artz, Rebekka R.;Benavides, Juan C.;Benscoter, Brian W.
泥炭地含有全球土壤碳的很大一部分，但这些储层将如何应对气候变化仍然相对未知。泥炭有机质化学变化的全球图景将有助于我们衡量泥炭地土壤对气候的反应。本研究的目的是验证以下假设：(a)泥炭碳水化合物含量（土壤有机质反应性的指标）随纬度增加而减少，(b)泥炭芳香含量（顽固性的指标）呈反比变化，(c)海拔与纬度有相似的影响。我们使用傅里叶变换红外光谱分析了1034份泥炭样品的有机官能团的变化，这些样品采集于10至20、30-40和60-70 cm深度的165个单独地点，纬度梯度为79°N-65°S，海拔为0 - 4773 m。高纬度泥炭的碳水化合物含量显著高于赤道附近的泥炭，而芳香含量则相反。同一纬度不同海拔的泥炭，碳水化合物含量高，芳香物质含量低。高纬度地区较高的碳水化合物含量表明矿化的可能性更大，而低纬度泥炭的化学成分与它们在较高温度下的相对稳定性是一致的。在赤道附近较温暖的地区，低碳水化合物和高芳香化合物的结合表明，高纬度泥炭的矿化直到在新的温度制度下达到顽固性。
Peatlands contain a significant fraction of global soil carbon, but how these reservoirs will respond to the changing climate is still relatively unknown. A global picture of the variations in peat organic matter chemistry will aid our ability to gauge peatland soil response to climate. The goal of this research is to test the hypotheses that (a) peat carbohydrate content, an indicator of soil organic matter reactivity, will increase with latitude and decrease with mean annual temperatures, (b) while peat aromatic content, an indicator of recalcitrance, will vary inversely, and (c) elevation will have a similar effect to latitude. We used Fourier Transform Infrared Spectroscopy to examine variations in the organic matter functional groups of 1034 peat samples collected from 10 to 20, 30–40, and 60–70 cm depths at 165 individual sites across a latitudinal gradient of 79°N–65°S and from elevations of 0–4,773 m. Carbohydrate contents of high latitude peat were significantly greater than peat originating near the equator, while aromatic content showed the opposite trend. For peat from similar latitudes but different elevations, the carbohydrate content was greater and aromatic content was lower at higher elevations. Higher carbohydrate content at higher latitudes indicates a greater potential for mineralization, whereas the chemical composition of low latitude peat is consistent with their apparent relative stability in the face of warmer temperatures. The combination of low carbohydrates and high aromatics at warmer locations near the equator suggests the mineralization of high latitude peat until reaching recalcitrance under a new temperature regime.