2026-10-06T11:07:00Z https://api.figshare.com/v2/oai

oai:figshare.com:article/31792345 2026-10-02T21:25:18Z category_25882 item_type_3 month_year_10_2026

Global convergence of optimal photosynthetic responses to atmospheric dryness Yan Guo (23577478) Lixin Wang (14163557) Ying Sun (21147954) Ecohydrology Gross Primary Productivity (GPP) Vapor pressure deficit (VPD) <p dir="ltr">Terrestrial gross primary productivity (GPP) is central to the global carbon cycle, and it is strongly constrained by atmospheric dryness (i.e., vapor pressure deficit, VPD). Most existing studies assume a monotonic decline in GPP with increasing VPD. Guided by an optimality framework, we predict that GPP responses to VPD are inherently non-monotonic and that an optimal VPD (i.e., the VPD at which the ecosystem shows peak GPP) exists. Using 162 FLUXNET sites globally, we found that more than 96% exhibited an optimal VPD. The ubiquitous optimal VPD is independently observed at the leaf scale using a global gas-exchange dataset. Interestingly, optimal VPD converges to mean ambient VPD across biomes and spatial scales (from leaf to ecosystem scales), driven by dynamic optimal-ambient VPD relationships over time. The results suggest a dynamic photosynthetic adjustment to atmospheric dryness. These findings establish a unified GPP-VPD relationship with implications for carbon-water coupling predictions under a warming and drying climate.</p> 2026-10-02T21:25:18Z Dataset Dataset 10.6084/m9.figshare.31792345.v1 https://figshare.com/articles/dataset/Global_convergence_of_optimal_photosynthetic_responses_to_atmospheric_dryness/31792345 CC BY 4.0