A wide variety of studies have estimated the magnitude of global terrestrial net primary production （NPP）, but its variations, both spatially and temporally, still remain uncertain. By using an improved process-base...A wide variety of studies have estimated the magnitude of global terrestrial net primary production （NPP）, but its variations, both spatially and temporally, still remain uncertain. By using an improved process-based terrestrial ecosystem model （DLEM, Dynamic Land Ecosystem Model）, we provide an estimate of global terrestrial NPP induced by multiple environmental factors and examine the response of terrestrial NPP to climate variability at biome and global levels and along latitudes throughout the first decade of the 21st century. The model simulation estimates an average global terrestrial NPP of 54.6 Pg C yr-1 during 2000-2009, varying from 52.8 Pg C yr-1 in the dry year of 2002 to 56.4 Pg C yr-1 in the wet year of 2008. In wet years, a large increase in terrestrial NPP compared to the decadal mean was prevalent in Amazonia, Africa and Australia. In dry years, however, we found a 3.2% reduction in global terrestrial NPP compared to the decadal mean, primarily due to limited moisture supply in tropical regions. At a global level, precipitation explained approximately 63% of the variation in terrestrial NPP, while the rest was attributed to changes in temperature and other environmental factors. Precipitation was the major factor determining inter-annual variation in terrestrial NPP in low-latitude regions. However, in midand high-latitude regions, temperature variability largely controlled the magnitude of terrestrial NPP. Our results imply that pro- jected climate warming and increasing climate extreme events would alter the magnitude and spatiotemporal patterns of global terrestrial NPP.展开更多
Microplastic(MP)pollution,a global environmental problem,has been recently studied in marine and freshwater environments.However,our understanding of MP effect on terrestrial ecosystems,especially carbon(C)and nitroge...Microplastic(MP)pollution,a global environmental problem,has been recently studied in marine and freshwater environments.However,our understanding of MP effect on terrestrial ecosystems,especially carbon(C)and nitrogen(N)turnover remains poor.This review summarizes the sources and distribution characteristics of MPs in terrestrial ecosystems and explores their effects on soil properties,plant growth,C and N turnover.Once entering the terrestrial ecosystem,MPs could involve in sequestrating carbon and nitrogen by changing soil properties(e.g.,pH,soil aggregate stability,and soil porosity).MPs could exert direct influences on plants or on soil physical environment and microbial metabolic environment to indirectly affect plant growth,thus altering the quantity and quality of soil C and N inputs by shifts in plant litter and roots.The changes of the dominant bacteria phyla,related functional genes,and enzymes caused by MP pollution could affect C and N cycles.Additionally,the MP effect varies with its properties(e.g.,types,shapes,elemental composition,functional groups,released additives).Future researches should unify the standard system of MP separation,detection,and reveal the ecological effects of MPs,especially their impacts on terrestrial carbon and nitrogen cycles in the context of climate changes.展开更多
基金NSF Decadal and Regional Climate Prediction using Earth System Models,No.AGS-1243220NSF Dynamics of Coupled Natural and Human Systems,No.1210360+2 种基金NSF Computer and Network Systems,No.CNS-1059376NASA Land Cover/Land Use Change Program,No.NNX08AL73G S01NASA Interdisciplinary Science Program,No.NNX10AU06G,No.NNX11AD47G
文摘A wide variety of studies have estimated the magnitude of global terrestrial net primary production （NPP）, but its variations, both spatially and temporally, still remain uncertain. By using an improved process-based terrestrial ecosystem model （DLEM, Dynamic Land Ecosystem Model）, we provide an estimate of global terrestrial NPP induced by multiple environmental factors and examine the response of terrestrial NPP to climate variability at biome and global levels and along latitudes throughout the first decade of the 21st century. The model simulation estimates an average global terrestrial NPP of 54.6 Pg C yr-1 during 2000-2009, varying from 52.8 Pg C yr-1 in the dry year of 2002 to 56.4 Pg C yr-1 in the wet year of 2008. In wet years, a large increase in terrestrial NPP compared to the decadal mean was prevalent in Amazonia, Africa and Australia. In dry years, however, we found a 3.2% reduction in global terrestrial NPP compared to the decadal mean, primarily due to limited moisture supply in tropical regions. At a global level, precipitation explained approximately 63% of the variation in terrestrial NPP, while the rest was attributed to changes in temperature and other environmental factors. Precipitation was the major factor determining inter-annual variation in terrestrial NPP in low-latitude regions. However, in midand high-latitude regions, temperature variability largely controlled the magnitude of terrestrial NPP. Our results imply that pro- jected climate warming and increasing climate extreme events would alter the magnitude and spatiotemporal patterns of global terrestrial NPP.
基金National Key R&D Program of China(2021YFD1700900)Central Public-interest Scientific Institution Basal Research Fund(2022-jbkyywf-wll)Cooperative Innovation Project of International Cooperation Program of CAAS(2022-wll).
文摘Microplastic(MP)pollution,a global environmental problem,has been recently studied in marine and freshwater environments.However,our understanding of MP effect on terrestrial ecosystems,especially carbon(C)and nitrogen(N)turnover remains poor.This review summarizes the sources and distribution characteristics of MPs in terrestrial ecosystems and explores their effects on soil properties,plant growth,C and N turnover.Once entering the terrestrial ecosystem,MPs could involve in sequestrating carbon and nitrogen by changing soil properties(e.g.,pH,soil aggregate stability,and soil porosity).MPs could exert direct influences on plants or on soil physical environment and microbial metabolic environment to indirectly affect plant growth,thus altering the quantity and quality of soil C and N inputs by shifts in plant litter and roots.The changes of the dominant bacteria phyla,related functional genes,and enzymes caused by MP pollution could affect C and N cycles.Additionally,the MP effect varies with its properties(e.g.,types,shapes,elemental composition,functional groups,released additives).Future researches should unify the standard system of MP separation,detection,and reveal the ecological effects of MPs,especially their impacts on terrestrial carbon and nitrogen cycles in the context of climate changes.
