Long-Term Warming Decreases Redox Capacity of Soil Organic Matter
Long-Term Warming Decreases Redox Capacity of Soil Organic Matter
复制标题
长期变暖降低土壤有机质的氧化还原能力
DOI：
10.1021/acs.estlett.0c00748
复制
发表时间：
2021
影响因子：
10.9
通讯作者：
Keiluweit, Marco
中科院分区：
文献类型：
--
作者：
LaCroix, Rachelle E.;Walpen, Nicolas;Sander, Michael;Tfaily, Malak M.;Blanchard, Jeffrey L.;Keiluweit, Marco
全球气温上升增加了微生物的活动，加速了土壤有机质（SOM）的分解。有机质具有多种功能，其中参与氧化还原反应的能力（或氧化还原能力）影响几乎所有的土壤生态地球化学过程。变暖引起的微生物分解如何影响SOM的氧化还原能力及其在土壤地球化学过程中的功能作用在很大程度上是未知的。我们研究了15年的原位石油变暖对水可提取有机物（WEOM）的氧化还原能力的影响。结合介导的电化学分析和高分辨率质谱，我们评估了加热（高于环境温度5°C）和非加热有机和矿物温带森林土壤中WEOM氧化还原能力变化的分子基础。慢性土壤变暖显着降低浓度和固有的电子接受和捐赠能力的WEOM，特别是在矿质土壤。这种下降是最好的解释芳香族和酚类化合物的相对丰度的减少，这表明增强微生物的氧化还原活性部分的分解引起的氧化还原能力的降低。我们的研究结果表明，全球变暖不仅减少了土壤碳库的大小，但也可能产生负面影响的SOM参与关键的氧化还原过程，如微生物呼吸，营养循环，或污染物降解的能力。
Globally rising temperatures increase microbial activity, accelerating decomposition of soil organic matter (SOM). SOM has numerous functional capabilities, of which the capacity to engage in reduction–oxidation reactions (or redox capacity) affects nearly all soil biogeochemical processes. How warming-induced microbial decomposition affects the redox capacity of SOM and its functional role in biogeochemical processes is largely unknown. We examined the impact of 15 years ofin situsoil warming on the redox capacities of water-extractable organic matter (WEOM). Combining mediated electrochemical analysis with high-resolution mass spectrometry, we assessed the molecular basis for changes in the redox capacities of WEOM within heated (5°C above ambient) and non-heated organic and mineral temperate forest soils. Chronic soil warming significantly decreased both concentrations and inherent electron-accepting and -donating capacities of WEOM, particularly in the mineral soil. This decline was best explained by decreases in the relative abundance of aromatic and phenolic compounds, suggesting that enhanced microbial decomposition of redox-active moieties caused the decrease in redox capacity. Our findings suggest that global warming not only diminishes the size of the soil carbon reservoir but might also negatively alter the ability of SOM to participate in critical redox processes such as microbial respiration, nutrient cycling, or contaminant degradation.