Nutrient resorption is an important conservation mechanism for plants to overcome nutrient limitation in the less fertile area of desertifled land. In the semi-arid Horqin Sandy Land of Northern China, the shrub Artem...Nutrient resorption is an important conservation mechanism for plants to overcome nutrient limitation in the less fertile area of desertifled land. In the semi-arid Horqin Sandy Land of Northern China, the shrub Artemisia ha/odendron usually colonizes into the bare ground of severely desertified land as a pioneer species. It is, therefore, expected that A. ha/odendron will be less dependent on current nutrient uptake through efficient and proficient re- sorption of nutrients. In this study, we found that averaged nitrogen （N） and phosphorus （P） concentrations in se- nesced leaves significantly varied from 12.3 and 1.2 mg/g in the shifting sand dune to 15.9 and 1.9 mg/g in the fixed sand dune, respectively, suggesting that foliar N and P resorption of A. ha/odendron were more proficient in the shifting sand dune. In particular, positive relationships between nutrient concentrations in senesced leaves and soil nutrient availability indicate that A. ha/odendron in infertile habitats is more likely to manage with a low level of nu- trients in senesced leaves, giving this species an advantage in infertile soil. Moreover, foliar N- and P-resorption efficiencies and proficiencies showed limited inter-annual variability although annual precipitation varied greatly among 2007-2009. However, N and P resorption of A. ha/oc/endron were not more efficient and proficient than those previously reported for other shrubs, indicating that the pioneer shrub in sand dune environments does not rely more heavily than other plants on the process of resorption to conserve nutrients. Incomplete resorption of nutrients in A. halodendron suggests that senesced-leaf fall would return litter with high quality to the soil, and thereby would indirectly improve soil nutrient availability. The restoration of desertified land, therefore, may be ac- celerated after A. halodendron pioneers into shifting sand dunes.展开更多
Atmospheric composition is an important indicator of habitability and life.The presence or absence of a large exomoon around an Earth-size exoplanet could have important consequences for planet climate stability.Thus ...Atmospheric composition is an important indicator of habitability and life.The presence or absence of a large exomoon around an Earth-size exoplanet could have important consequences for planet climate stability.Thus the detection of exomoons and retrieval of information regarding atmospheric composition of Earth-size exoplanets are important goals of future exoplanet observations.Here a data analysis method is developed to achieve both goals simultaneously,based on reflection spectra of exoplanet-exomoon systems.We show that the existence of exomoons,the size of exomoons,and the concentrations of some atomic and molecular species in the atmospheres of their hosting Earth-like exoplanets can be retrieved with high levels of reliability.In addition,the method can provide well-constrained fractions of basic surface types on the targets because of the characteristic spectral features of atmospheric species and surface types in the analyzed spectral range.展开更多
Precise and high-resolution carbon dioxide(CO_(2))emission data is of great importance in achieving carbon neutrality around the world.Here we present for the first time the near-real-time Global Gridded Daily CO_(2)E...Precise and high-resolution carbon dioxide(CO_(2))emission data is of great importance in achieving carbon neutrality around the world.Here we present for the first time the near-real-time Global Gridded Daily CO_(2)Emissions Dataset(GRACED)from fossil fuel and cement production with a global spatial resolution of 0.1°by 0.1°and a temporal resolution of 1 day.Gridded fossil emissions are computed for different sectors based on the daily national CO_(2)emissions from near-real-time dataset(Carbon Monitor),the spatial patterns of point source emission dataset Global Energy Infrastructure Emissions Database(GID),Emission Database for Global Atmospheric Research(EDGAR),and spatiotemporal patters of satellite nitrogen dioxide(NO2)retrievals.Our study on the global CO_(2)emissions responds to the growing and urgent need for high-quality,fine-grained,near-real-time CO_(2)emissions estimates to support global emissions monitoring across various spatial scales.Weshow the spatial patterns of emission changes for power,industry,residential consumption,ground transportation,domestic and international aviation,and international shipping sectors from January 1,2019,to December 31,2020.This gives thorough insights into the relative contributions from each sector.Furthermore,it provides the most up-to-date and fine-grained overview of where and when fossil CO_(2)emissions have decreased and rebounded in response to emergencies(e.g.,coronavirus disease 2019[COVID-19])and other disturbances of human activities of any previously published dataset.As the world recovers from the pandemic and decarbonizes its energy systems,regular updates of this dataset will enable policymakers to more closely monitor the effectiveness of climate and energy policies and quickly adapt.展开更多
基金National Key Technology R&D Program (Y113911001)Strategic Priority Research Program of the Chinese Academy of Sciences (XDA05050406)National Natural Science Foundation of China (31270501, 30970471)
文摘Nutrient resorption is an important conservation mechanism for plants to overcome nutrient limitation in the less fertile area of desertifled land. In the semi-arid Horqin Sandy Land of Northern China, the shrub Artemisia ha/odendron usually colonizes into the bare ground of severely desertified land as a pioneer species. It is, therefore, expected that A. ha/odendron will be less dependent on current nutrient uptake through efficient and proficient re- sorption of nutrients. In this study, we found that averaged nitrogen （N） and phosphorus （P） concentrations in se- nesced leaves significantly varied from 12.3 and 1.2 mg/g in the shifting sand dune to 15.9 and 1.9 mg/g in the fixed sand dune, respectively, suggesting that foliar N and P resorption of A. ha/odendron were more proficient in the shifting sand dune. In particular, positive relationships between nutrient concentrations in senesced leaves and soil nutrient availability indicate that A. ha/odendron in infertile habitats is more likely to manage with a low level of nu- trients in senesced leaves, giving this species an advantage in infertile soil. Moreover, foliar N- and P-resorption efficiencies and proficiencies showed limited inter-annual variability although annual precipitation varied greatly among 2007-2009. However, N and P resorption of A. ha/oc/endron were not more efficient and proficient than those previously reported for other shrubs, indicating that the pioneer shrub in sand dune environments does not rely more heavily than other plants on the process of resorption to conserve nutrients. Incomplete resorption of nutrients in A. halodendron suggests that senesced-leaf fall would return litter with high quality to the soil, and thereby would indirectly improve soil nutrient availability. The restoration of desertified land, therefore, may be ac- celerated after A. halodendron pioneers into shifting sand dunes.
基金supported by the National Natural Science Foundation of China(1166116101,4164104)supported by the National Natural Science Foundation of China(41375102)+5 种基金support from the Spark Program,Tsinghua Universitysupport from "Institute National des Sciences de l’Univers"(INSU)the "Centre National de la Recherche Scientifique"(CNRS) and "Centre National d’Etude Spatiale"(CNES),through the "Programme National de Planétologie"the PICS programMEX/OMEGAMEX/PFS programs
文摘Atmospheric composition is an important indicator of habitability and life.The presence or absence of a large exomoon around an Earth-size exoplanet could have important consequences for planet climate stability.Thus the detection of exomoons and retrieval of information regarding atmospheric composition of Earth-size exoplanets are important goals of future exoplanet observations.Here a data analysis method is developed to achieve both goals simultaneously,based on reflection spectra of exoplanet-exomoon systems.We show that the existence of exomoons,the size of exomoons,and the concentrations of some atomic and molecular species in the atmospheres of their hosting Earth-like exoplanets can be retrieved with high levels of reliability.In addition,the method can provide well-constrained fractions of basic surface types on the targets because of the characteristic spectral features of atmospheric species and surface types in the analyzed spectral range.
基金the National Natural Science Foundation of China(grants 41921005 and 71874097)Beijing Natural Science Foundation(JQ19032)the Qiu Shi Science&Technologies Foundation.
文摘Precise and high-resolution carbon dioxide(CO_(2))emission data is of great importance in achieving carbon neutrality around the world.Here we present for the first time the near-real-time Global Gridded Daily CO_(2)Emissions Dataset(GRACED)from fossil fuel and cement production with a global spatial resolution of 0.1°by 0.1°and a temporal resolution of 1 day.Gridded fossil emissions are computed for different sectors based on the daily national CO_(2)emissions from near-real-time dataset(Carbon Monitor),the spatial patterns of point source emission dataset Global Energy Infrastructure Emissions Database(GID),Emission Database for Global Atmospheric Research(EDGAR),and spatiotemporal patters of satellite nitrogen dioxide(NO2)retrievals.Our study on the global CO_(2)emissions responds to the growing and urgent need for high-quality,fine-grained,near-real-time CO_(2)emissions estimates to support global emissions monitoring across various spatial scales.Weshow the spatial patterns of emission changes for power,industry,residential consumption,ground transportation,domestic and international aviation,and international shipping sectors from January 1,2019,to December 31,2020.This gives thorough insights into the relative contributions from each sector.Furthermore,it provides the most up-to-date and fine-grained overview of where and when fossil CO_(2)emissions have decreased and rebounded in response to emergencies(e.g.,coronavirus disease 2019[COVID-19])and other disturbances of human activities of any previously published dataset.As the world recovers from the pandemic and decarbonizes its energy systems,regular updates of this dataset will enable policymakers to more closely monitor the effectiveness of climate and energy policies and quickly adapt.
