2025-07-17 中国科学院(CAS)
＜関連情報＞
- https://english.cas.cn/newsroom/research_news/earth/202507/t20250718_1047594.shtml
- https://www.sciencedirect.com/science/article/abs/pii/S0022169425010017?via%3Dihub
地下水の影響を受けた超乾燥生態系では生産性が向上しているにもかかわらず、炭素貯留の可能性は限られている Limited carbon sequestration potential despite enhanced productivity in groundwater-influenced hyper-arid ecosystems
Mengtao Ci, Xingming Hao, Sen Zhang, Fan Sun, Qixiang Liang, Xue Fan, Jingjing Zhang, Xuewei Li, Haibing Xiong
Journal of Hydrology Available online: 6 June 2025
DOI:https://doi.org/10.1016/j.jhydrol.2025.133663
Graphical abstract
Highlights
- Water transfer impacts groundwater, vegetation productivity in the lower Tarim River corridor.
- NPP and NEP were estimated using the groundwater-enhanced CASA model.
- Higher groundwater increased NPP and NEP, but the area remained a carbon source.
- NPP and NEP were inhibited when the groundwater level dropped below certain levels.
- Convergent cross-mapping showed that groundwater level strongly affected NPP.
Abstract
Groundwater level (GWL) fluctuations significantly affect carbon cycling in hyper-arid ecosystems. However, the impacts of GWL fluctuations on carbon cycling in the lower Tarim River and the mechanisms driving these changes are poorly understood. Accordingly, the effects of GWL changes on the net primary productivity (NPP) and net ecosystem productivity (NEP) in the riparian corridor of the lower Tarim River were investigated in this study using an improved Carnegie–Ames–Stanford Approach model. An increase in GWL resulting from ecological water transfer was found to enhance both the NPP and NEP. However, the riparian corridor remained a net carbon source as the maximum carbon sink area accounted for only 30.8 % of the study region. The analysis results also revealed a nonlinear and threshold-based relationship between the GWL and carbon cycling, in which the NPP and NEP were significantly inhibited when the GWL dropped below –4.84 m and –4.44 m, respectively. Finally, convergent cross mapping revealed that the GWL had a greater causal effect on the NPP than on the NEP. These findings provide a robust scientific basis for optimising ecosystem management strategies to enhance carbon sequestration in hyper-arid regions.
