美国俄勒冈大学Hunter, Brooke D.团队研究了侵蚀地貌中土壤有机碳库丰度和持久性的地貌控制。相关论文于2024年1月29日发表于国际顶尖学术期刊《自然—地球科学》杂志上。
研究人员使用地形和土壤生物地球化学分析表明，在研究区域的16个站点中，随着模拟侵蚀速率从21.0到至0.2 kg m-2和12.0至0.1 kg m-2，总有机碳储量和典型的循环较慢的有机碳矿物相关组分呈指数下降。沿着大于一个数量级的侵蚀梯度，放射性碳(Δ14C)、土壤厚度和质地数据分别呈现更年轻、更薄和更粗糙的趋势，表明快速侵蚀场地的有机碳含量远低于缓慢侵蚀场地，并且主要由循环更快的有机碳库控制。
通过将这些侵蚀驱动的土壤和有机碳趋势与高分辨率地形数据相结合，可以很容易地应用山顶凸度和其他侵蚀速率指标，来估算不同景观环境中的有机碳丰度和持久性，从而提高研究在一系列时空尺度上预测碳动态的能力。
据介绍，土壤在全球碳循环中发挥着核心作用，是自然气候解决方案的关键组成部分，需要对局部到区域尺度的土壤有机碳(SOC)动态进行定量预测。在丘陵和山区中，隆升和河流切割的变化会产生侵蚀梯度和山坡形态，从而控制着影响有机碳丰度和持久性的土壤性质。
附：英文原文
Title: Geomorphic controls on the abundance and persistence of soil organic carbon pools in erosional landscapes
Author: Hunter, Brooke D., Roering, Joshua J., Silva, Lucas C. R., Moreland, Kimber C.
Issue&Volume: 2024-01-29
Abstract: Soils play a central role in the global carbon cycle and constitute a key component of natural climate solutions that require quantitative predictions of soil organic carbon (SOC) dynamics at local to regional scales. In hilly and mountainous terrain, variations in uplift and stream incision generate gradients in erosion and hillslope morphology that control soil properties that impact the abundance and persistence of SOC. Here we use topographic and soil biogeochemical analyses to show that across 16 sites in our study region, total SOC stocks and the typically slower-cycling mineral-associated fraction of SOC decrease exponentially with modelled erosion rate from 21.0 to 0.2kg m–2 and 12.0 to 0.1kg m–2, respectively. Along the greater than order-of-magnitude erosional gradient, radiocarbon (Δ14C), soil thickness and texture data trend younger, thinner and coarser, respectively, such that fast-eroding sites have much less SOC than slow-eroding sites and are dominated by faster-cycling SOC pools. By coupling these erosion-driven soil and SOC trends with high-resolution topographic data, hilltop convexity and other erosion rate metrics can be readily applied to estimate SOC abundance and persistence in diverse landscape settings, facilitating our ability to predict carbon dynamics across a range of spatiotemporal scales.
DOI: 10.1038/s41561-023-01365-2
Source: https://www.nature.com/articles/s41561-023-01365-2