Meyer Vera D, Köhler Peter, Smit Nadine T, Lipp Julius S, Wei Bingbing, Mollenhauer Gesine, Schefuß Enno
MARUM - Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany.
Alfred-Wegener-Institut Helmholtz Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany.
Nat Commun. 2025 May 15;16(1):4530. doi: 10.1038/s41467-025-59013-9.
Carbon storage in soils is important in regulating atmospheric carbon dioxide (CO). However, the sensitivity of the soil-carbon turnover time (τ) to temperature and hydrology forcing is not fully understood. Here, we use radiocarbon dating of plant-derived lipids in conjunction with reconstructions of temperature and rainfall from an eastern Mediterranean sediment core receiving terrigenous material from the Nile River watershed to investigate τin subtropical and tropical areas during the last 18,000 years. We find that τ was reduced by an order of magnitude over the last deglaciation and that temperature was the major driver of these changes while the impact of hydroclimate was relatively small. We conclude that increased CO efflux from soils into the atmosphere constituted a positive feedback to global warming. However, simulated glacial-to-interglacial changes in a dynamic global vegetation model underestimate our data-based reconstructions of soil-carbon turnover times suggesting that this climate feedback is underestimated.
土壤中的碳储存对于调节大气二氧化碳（CO）至关重要。然而，土壤碳周转时间（τ）对温度和水文强迫的敏感性尚未完全了解。在这里，我们利用植物源脂质的放射性碳测年，结合来自接收尼罗河流域陆源物质的东地中海沉积物岩芯的温度和降雨重建，来研究过去18000年亚热带和热带地区的τ。我们发现，在末次冰消期，τ降低了一个数量级，温度是这些变化的主要驱动因素，而水文气候的影响相对较小。我们得出结论，土壤向大气中增加的CO排放构成了对全球变暖的正反馈。然而，动态全球植被模型中模拟的冰期到间冰期变化低估了我们基于数据的土壤碳周转时间重建，这表明这种气候反馈被低估了。
