Jiao Fusheng, Xu Xiaojuan, Xue Peng, Gong Haibo, Liu Xiang, Liu Jing, Zhang Kun, Yang Yue, Qiu Jie, Zou Changxin
School of Geography, Nanjing Normal University, Nanjing, 210023, China.
Nanjing Institute of Environmental Sciences (NIES), Ministry of Ecology and Environment (MEE), Nanjing, 210042, China.
J Environ Manage. 2025 Feb;374:124030. doi: 10.1016/j.jenvman.2025.124030. Epub 2025 Jan 11.
Terrestrial ecosystem carbon sinks are a natural deposit that absorbs carbon from the atmosphere. A stable land carbon sink facilitates more reliable predictions of carbon sequestration under changing climate conditions. In contrast, a highly variable land carbon sink will introduce significant uncertainty into model predictions. Karst regions have attracted increasing attention due to their significant contribution to global land carbon sequestration capacity. However, understanding the stability of land carbon sinks and its driving factors in karst areas remains limited. This study focused on the world's largest karst zone, located in Southwest China (SWC), to assess the stability of land carbon sinks. By analyzing inter-annual variation (IAV) in net ecosystem productivity (NEP), we aimed to elucidate the spatial distribution of the stability of land carbon sinks and the dominant climatic drivers. We compared the stability of land carbon sinks across bedrocks, which were classified by carbonate content: non-karst, Discontinuous Carbonate Rocks (DCR), and Continuous Carbonate Rocks (CCR). Our findings showed that while land carbon sinks in karst bedrocks exhibited higher increased NEP rates than those in non-karst areas. Notably, we observed an inverse relationship between the rate and stability-regions with rapid land carbon sink enhancement were often characterized by instability, particularly in karst areas. Moreover, the drivers of the stability of land carbon sinks varied significantly between bedrock types. In non-karst regions, water availability was the primary factor influencing stability, whereas temperature was more dominant in karst regions. DCR regions showed lower stability due to the high sensitivity of land carbon sinks to temperature, while CCR regions experienced reduced stability linked to greater temperature variability. Our results highlight the need to consider the combined effects of bedrock type and climate factors on stability, offering valuable insights for managing and enhancing carbon sequestration capacity in a changing environment.
陆地生态系统碳汇是一种从大气中吸收碳的自然沉积物。稳定的陆地碳汇有助于在气候变化条件下更可靠地预测碳固存。相比之下，高度可变的陆地碳汇会给模型预测带来重大不确定性。喀斯特地区因其对全球陆地碳固存能力的重大贡献而受到越来越多的关注。然而，对喀斯特地区陆地碳汇稳定性及其驱动因素的了解仍然有限。本研究聚焦于位于中国西南部（SWC）的世界最大喀斯特地区，以评估陆地碳汇的稳定性。通过分析净生态系统生产力（NEP）的年际变化（IAV），我们旨在阐明陆地碳汇稳定性的空间分布以及主要气候驱动因素。我们比较了不同基岩类型的陆地碳汇稳定性，这些基岩根据碳酸盐含量分类为：非喀斯特、不连续碳酸盐岩（DCR）和连续碳酸盐岩（CCR）。我们的研究结果表明，虽然喀斯特基岩中的陆地碳汇比非喀斯特地区表现出更高的NEP增长率。值得注意的是，我们观察到增长率与稳定性之间存在反比关系——陆地碳汇快速增强的地区通常具有不稳定性，特别是在喀斯特地区。此外，不同基岩类型的陆地碳汇稳定性驱动因素差异显著。在非喀斯特地区，水分可利用性是影响稳定性的主要因素，而在喀斯特地区温度更为重要。由于陆地碳汇对温度高度敏感，DCR地区表现出较低的稳定性，而CCR地区由于温度变率较大，稳定性降低。我们的结果强调需要考虑基岩类型和气候因素对稳定性的综合影响，为在变化环境中管理和提高碳固存能力提供了有价值的见解。
