No abstract

Ecosystems on the Tibetan Plateau are particularly sensitive to climate change. Significant advances have been made toward understanding the effects of climate change on the vegetation productivity of the plateau by using satellite observations, but a comprehensive study including various satellite measurements has yet to be presented. Here, we analyze the spatiotemporal variability in Tibetan vegetation productivity using a variety of proxies, including the Normalized Difference Vegetation Index, Enhanced Vegetation Index, Near‐Infrared Reflectance of vegetation, and Solar‐Induced chlorophyll Fluorescence. First, in terms of productivity responses to seasonal climate variation, Near‐Infrared Reflectance of vegetation‐ and Solar‐Induced chlorophyll Fluorescence‐based growing season length had better correlation with eddy covariance site measurements and was ~50 days shorter than those of the other proxies. Second, all proxies, except the Normalized Difference Vegetation Index derived from Système Probatoire d'Observation de la Terre, displayed a dipole‐like trend pattern, similar to the observed north‐south dipole pattern of precipitation change. This result is explained by the finding that moisture is a dominant driver controlling the interannual variation in productivity. Third, we analyzed the long‐term responses of vegetation productivity to the precipitation regime and found four distinct productivity regimes, desert steppe, alpine steppe, meadow, and shrub/forests, indicating that Tibetan productivity varies with precipitation in a nonlinear way. The result offers insights into how Tibetan vegetation will respond to future climate change. Our results provide a multisatellite perspective on the impacts of climate change on spatiotemporal variation in productivity and suggest an urgent need to improve Tibetan productivity simulation.

In clinical practice, it has become urgent to develop multifunctional wound dressings that can combat infection and prompt wound healing simultaneously. In this study, we proposed a polydopamine/alginate/nanoselenium composite hydrogel (Alg-PDA-Se) for the treatment of infected wounds. In particular, polydopamine endows the composite hydrogel with controllable near-infrared photothermal properties, while low-dosage selenium nanoparticles (Se NPs) offer excellent anti-oxidation, anti-inflammatory, pro-proliferative, pro-migration, and pro-angiogenic performances, which are verified by multiple cells, including macrophages, fibroblasts, and endothelial cells. More interestingly, the combination of mild temperature with low-dosage Se NPs produces a synergistic effect on combating both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) and promoting the healing of bacteria-infected wounds in vivo. We anticipate that the designed composite hydrogel might be a potential candidate for anti-infection bioactive dressing.