美国劳伦斯利弗莫尔实验室Georgiou, Katerina小组在研究矿物组合驱动的土壤有机碳的温度敏感性中取得新进展。2024年2月20日出版的《自然—地球科学》杂志发表了这项成果。

研究人员分析了观测得出的土壤碳库的全球估计值，以量化它们的相对比例，并计算它们对气候温度的敏感性，因为碳含量随温度升高而下降。研究发现，颗粒碳的气候温度敏感性平均比矿物相关碳高28%，在凉爽气候条件下最高可达53%。此外，这些潜在的土壤碳库之间的碳分布，驱动着大量土壤碳储量的紧急气候温度敏感性。

然而，全球模型对土壤碳库分布的预测差异很大。研究人员发现，在耦合模型比较项目第6阶段的地球系统模型和离线陆地模型中，概念上类似于矿物保护碳的模型库的全球比例在16%到85%之间，这对土壤碳年龄和生态系统响应性具有重要意义。为了提高碳循环—气候反馈预测的准确性，需要对潜在的土壤碳库进行评估，以准确预测土壤碳的分布和脆弱性。

研究人员表示，土壤有机质分解及其与气候的相互作用取决于有机质是否与土壤矿物质相关。然而，数据限制阻碍了矿物相关和颗粒土壤有机碳库的全球尺度分析，以及在用于估计碳循环—气候反馈的地球系统模型中的基准测试。

附：英文原文

Title: Emergent temperature sensitivity of soil organic carbon driven by mineral associations

Author: Georgiou, Katerina, Koven, Charles D., Wieder, William R., Hartman, Melannie D., Riley, William J., Pett-Ridge, Jennifer, Bouskill, Nicholas J., Abramoff, Rose Z., Slessarev, Eric W., Ahlstrm, Anders, Parton, William J., Pellegrini, Adam F. A., Pierson, Derek, Sulman, Benjamin N., Zhu, Qing, Jackson, Robert B.

Issue&Volume: 2024-02-20

Abstract: Soil organic matter decomposition and its interactions with climate depend on whether the organic matter is associated with soil minerals. However, data limitations have hindered global-scale analyses of mineral-associated and particulate soil organic carbon pools and their benchmarking in Earth system models used to estimate carbon cycle–climate feedbacks. Here we analyse observationally derived global estimates of soil carbon pools to quantify their relative proportions and compute their climatological temperature sensitivities as the decline in carbon with increasing temperature. We find that the climatological temperature sensitivity of particulate carbon is on average 28% higher than that of mineral-associated carbon, and up to 53% higher in cool climates. Moreover, the distribution of carbon between these underlying soil carbon pools drives the emergent climatological temperature sensitivity of bulk soil carbon stocks. However, global models vary widely in their predictions of soil carbon pool distributions. We show that the global proportion of model pools that are conceptually similar to mineral-protected carbon ranges from 16 to 85% across Earth system models from the Coupled Model Intercomparison Project Phase 6 and offline land models, with implications for bulk soil carbon ages and ecosystem responsiveness. To improve projections of carbon cycle–climate feedbacks, it is imperative to assess underlying soil carbon pools to accurately predict the distribution and vulnerability of soil carbon.

DOI: 10.1038/s41561-024-01384-7

Source: https://www.nature.com/articles/s41561-024-01384-7