Nature Communications ( IF 14.7 ) Pub Date : 2023-04-13 , DOI: 10.1038/s41467-023-37766-5
Jannik Martens 1, 2 , Carsten W Mueller 3, 4 , Prachi Joshi 5 , Christoph Rosinger 6, 7, 8 , Markus Maisch 5 , Andreas Kappler 5, 9 , Michael Bonkowski 6 , Georg Schwamborn 10, 11 , Lutz Schirrmeister 10 , Janet Rethemeyer 1
Ice-rich Pleistocene-age permafrost is particularly vulnerable to rapid thaw, which may quickly expose a large pool of sedimentary organic matter (OM) to microbial degradation and lead to emissions of climate-sensitive greenhouse gases. Protective physico-chemical mechanisms may, however, restrict microbial accessibility and reduce OM decomposition; mechanisms that may be influenced by changing environmental conditions during sediment deposition. Here we study different OM fractions in Siberian permafrost deposited during colder and warmer periods of the past 55,000 years. Among known stabilization mechanisms, the occlusion of OM in aggregates is of minor importance, while 33-74% of the organic carbon is associated with small, <6.3 µm mineral particles. Preservation of carbon in mineral-associated OM is enhanced by reactive iron minerals particularly during cold and dry climate, reflected by low microbial CO2 production in incubation experiments. Warmer and wetter conditions reduce OM stabilization, shown by more decomposed mineral-associated OM and up to 30% higher CO2 production. This shows that considering the stability and bioavailability of Pleistocene-age permafrost carbon is important for predicting future climate-carbon feedback.
中文翻译:
更新世永久冻土中矿物相关有机碳的稳定
富含冰的更新世时代永久冻土特别容易受到快速解冻的影响,这可能会迅速将大量沉积有机物 (OM) 暴露给微生物降解,并导致对气候敏感的温室气体排放。然而,保护性物理化学机制可能会限制微生物的可及性并减少 OM 分解;沉积物沉积过程中环境条件变化可能影响的机制。在这里,我们研究了过去 55,000 年较冷和较暖时期沉积的西伯利亚永久冻土中不同的 OM 组分。在已知的稳定机制中,聚集体中 OM 的吸留不太重要,而 33-74% 的有机碳与小于 6.3 µm 的小矿物颗粒相关。2生产孵化实验。更温暖和更潮湿的条件会降低 OM 的稳定性,表现为更多分解的矿物相关 OM 和高达 30% 的 CO 2产量。这表明考虑更新世多年冻土碳的稳定性和生物有效性对于预测未来气候-碳反馈具有重要意义。