Mapping turnover of dissolved organic carbon in global topsoil
Mapping turnover of dissolved organic carbon in global topsoil
复制标题
绘制全球表土中溶解有机碳的周转率
DOI：
10.1016/j.scitotenv.2023.167621
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发表时间：
2024
影响因子：
9.8
通讯作者：
Zhang, Lihua
中科院分区：
文献类型：
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作者：
Guo, Ziyu;Wang, Yihui;Liu, Jianzhao;He, Liyuan;Zhu, Xinhao;Zuo, Yunjiang;Wang, Nannan;Yuan, Fenghui;Sun, Ying;Zhang, Lihua
溶解有机碳（DOC）是有机碳的不稳定组分，是微生物的主要底物。因此，DOC的周转在土壤微生物呼吸中占主导地位。我们编制了0-30 cm土壤剖面DOC周转率的全球数据集（1096个数据点），并将数据与机器学习算法集成，以开发全球表土DOC周转率的全球地图。全球0-30 cm土壤DOC周转率平均为0.0087天-1，生物群落之间存在相当大的差异。DOC周转速率最快的是热带森林（0.0175d-1），最低的是苔原（0.0036d-1），表现出从低纬度到高纬度递减的趋势。DOC周转率主要受土壤和气候因素的控制，证实了结构方程模型和Mental检验的分析。通过机器学习算法，我们制作了每月规模的DOC周转率全球地图，并将其与DOC密度的全球数据集进一步结合，以生成表层土壤DOC周转的碳矿化月度地图。全球地球仪表层土壤DOC的年碳释放量估计为27.98 Pg C year-1，其中森林生物群落的贡献最大，其次是牧场和草地。冻原的DOC释放的碳最少，这是由于其低周转率受到低温的抑制。生物群落和全球尺度的DOC周转率和DOC的碳释放信息为生态系统模型提供了一个基准，以更好地预测土壤碳动态及其对全球碳循环的贡献。
Dissolved organic carbon (DOC), the labile fraction of organic carbon, is a predominant substrate for microbes. Therefore, the turnover of DOC dominates microbial respiration in soils. We compiled a global dataset (1096 data points) of the turnover rates of DOC in 0–30 cm soil profiles and integrated the data with a machine learning algorithm to develop a global map of DOC turnover rate in global topsoil. The global DOC turnover rate in 0–30 cm soil was averaged as 0.0087 day−1, with a considerable variation among biomes. The fastest DOC turnover rate was found in tropical forests (0.0175 day−1) and the lowest in tundra (0.0036 day−1), exhibiting a declining trend from low to high latitudes. The DOC turnover rate is primarily controlled by edaphic and climate factors, as confirmed by the analyses with the structural equation model and the Mental's test. With a machine learning algorithm, we produced global maps of DOC turnover rate at a monthly scale, which were further combined with a global dataset of DOC density to produce monthly maps of carbon mineralization from DOC turnover in topsoil. The annual carbon release from DOC was estimated as 27.98 Pg C year−1from topsoil across the globe, with the largest contribution from forest biomes, followed by pasture and grassland. Tundra released the least carbon from DOC due to its low turnover rate suppressed by low temperatures. The biome- and global-scale information of DOC turnover rate and carbon release from DOC provide a benchmark for ecosystem models to better project soil carbon dynamics and their contributions to global carbon cycling in the changing environment.