The past few decades have seen a resurgence of Interest in biological allometry. Specifically, a number of recent studies has suggested a -4/3 Invariant scaling relationship between mass and density that Is universall...The past few decades have seen a resurgence of Interest in biological allometry. Specifically, a number of recent studies has suggested a -4/3 Invariant scaling relationship between mass and density that Is universally valid for tree-dominated communities, regardless of their phyietic affiliation or habitat. In the present study, we test this scaling relationship using a comprehensive forest biomass database, Including 1 266 plots of six blomes and 17 forest types across China. The present study shows that the scaling exponent of the massdensity relationship varies across different tree-dominated communities and habitats. This great variability In the scaling exponent makes any generalization unwarranted. Although Inappropriate regression methods can lead to flawed estimation of the scaling exponent, inconsistency of theoretical framework and empirical patterns may have undermined the validity of previous work.展开更多
The scaling relationship between leaf area and total mass of plant has important implications for understanding resource allocations in the plant.The model of West,Brown and Enquist(WBE model)considers that a 3/4 scal...The scaling relationship between leaf area and total mass of plant has important implications for understanding resource allocations in the plant.The model of West,Brown and Enquist(WBE model)considers that a 3/4 scaling exponent of metabolic rate versus total mass to be optimal for each plant and has been confirmed numerous times.Although leaf area is a better proxy of the metabolic rate than leaf mass,few studies have focused on the scaling exponent of leaf area versus total mass and even fewer have discussed the diversification of this scaling exponent across different conditions.Here,I analyzed the scaling exponent of leaf area versus total mass of sample plots across world plants.I found that as the plant grows,it allocates fewer resources to photosynthetic tissues than expected by the WBE model.The results also empirically show that this scaling exponent varies significantly for different plant leaf habit,taxonomic class and geographic region.Therefore,leaf strategy in response to environmental pressure and constraint clearly plays a significant role.展开更多
Leaf nitrogen(N) and phosphorus(P) concentrations are critical for photosynthesis, growth, reproduction and other ecological processes of plants. Previous studies on large-scale biogeographic patterns of leaf N and P ...Leaf nitrogen(N) and phosphorus(P) concentrations are critical for photosynthesis, growth, reproduction and other ecological processes of plants. Previous studies on large-scale biogeographic patterns of leaf N and P stoichiometric relationships were mostly conducted using data pooled across taxa, while family/genus-level analyses are rarely reported. Here, we examined global patterns of family-specific leaf N and P stoichiometry using a global data set of 12,716 paired leaf N and P records which includes 204 families, 1,305 genera, and 3,420 species. After determining the minimum size of samples(i.e., 35 records), we analyzed leaf N and P concentrations, N:P ratios and N^P scaling relationships of plants for 62 families with 11,440 records. The numeric values of leaf N and P stoichiometry varied significantly across families and showed diverse trends along gradients of mean annual temperature(MAT) and mean annual precipitation(MAP). The leaf N and P concentrations and N:P ratios of 62 families ranged from 6.11 to 30.30 mg g–1, 0.27 to 2.17 mg g–1, and 10.20 to 35.40, respectively. Approximately 1/3–1/2 of the families(22–35 of 62) showed a decrease in leaf N and P concentrations and N:P ratios with increasing MAT or MAP, while the remainder either did not show a significant trend or presented the opposite pattern. Family-specific leaf N^P scaling exponents did not converge to a certain empirical value, with a range of 0.307–0.991 for 54 out of 62 families which indicated a significant N^P scaling relationship. Our results for the first time revealed large variation in the family-level leaf N and P stoichiometry of global terrestrial plants and that the stoichiometric relationships for at least one-third of the families were not consistent with the global trends reported previously. The numeric values of the family-specific leaf N and P stoichiometry documented in the current study provide critical synthetic parameters for biogeographic modeling and for further studies on the physiological and ecologica展开更多
Palaeodrainage basin,as an important component of the source-to-sink system,contains critical information on provenance and palaeoenvironment.Previous studies indicate that the scaling relationships of source-to-sink ...Palaeodrainage basin,as an important component of the source-to-sink system,contains critical information on provenance and palaeoenvironment.Previous studies indicate that the scaling relationships of source-to-sink system components generally follow power laws,and channel-belt thickness represents a reliable first-order proxy for the drainage area.In this study,a database of borehole cores and geophysical well logs of the Jurassic coal measures from Saishiteng area in the northern Qaidam Basin was used to reconstruct the palaeogeography,and to identify single-story channel-belts.Three palaeochannels,namely,River A,River B and River C,were identified which were persistent throughout the Dameigou and Shimengou Formations during the Middle Jurassic.The mean channel-belt thicknesses of River A,River B and River C in the Dameigou Formation were 9.8 m,8.9 m and 7.9 m,respectively,and those in the Shimengou Formation were 7.4 m,6.2 m and 5.4 m,respectively.We estimate the drainage area of three major rivers by using scaling relationships between drainage area and channel-belt thickness.The drainage areas of River A,River B and River C in the Dameigou Formation were 63.0×10~3 km^2,50.1×10~3 km^2 and 37.7×10~3 km^2,respectively,and those in the Shimengou Formation were 32.3×10~3 km^2,21.2×10~3 km^2 and15.3×10~3 km^2,respectively.The drainage basin lengths of River A,River B and River C in the Dameigou Formation were 300.4 km,239 km and 180.2 km,respectively,and those in the Shimengou Formation were 154.3 km,101.3 km and 73.1 km,respectively.For both the Dameigou and Shimengou Formations,River A showed the largest scale,followed by River B and River C succeedingly,which was mainly determined by the stretch direction of provenance in the southern Qilian Mountains.The variations of channel-belt thickness,drainage area and drainage basin length between Dameigou and Shimengou Formations are the response of source-to-sink system to the transformation from extension to compression depression during the Middle Jurassic in展开更多
Landslides produce large quantities of sediment deposits and reduce reservoir life. This study investigated landslides at the Shihmen Reservoir basin in Taiwan that were induced by Typhoon Sinlaku and Typhoon Jangmi i...Landslides produce large quantities of sediment deposits and reduce reservoir life. This study investigated landslides at the Shihmen Reservoir basin in Taiwan that were induced by Typhoon Sinlaku and Typhoon Jangmi in 2008. We formulate scaling relationships between landslide erosion volume and area and conclude that sediment budget can be estimated based on the easier-todetermine landslide erosion area. The methodologies applied for the investigation were geomorphological analysis through 5 m × 5 m digital terrain models(DTMs) of the basin created before and after the landslide events and spatial analysis through a geographic information system. The erosion area and volume of landslides were measured through the subtraction of DTMs produced before and after the events. Statistical analysis revealed that the landslide erosion frequency–magnitude distribution exhibited power-law behaviors with a scaling exponent of 2.15 for the frequency–area distribution and 1.66 for the frequency–volume distribution. This paper proposes different scaling relationships for different moving depths, and landslide erosion volumes were estimated on the basis of depth; thus, landslides of different scales can be distinguished to avoid errors in volume estimation. Two different scaling exponents are proposed: 1.21 for landslide erosions with depths of less than 2 m and 1.01 for landslide erosions with depths of more than 2 m. The proposed scaling relationships are practical for landslide erosion volume estimation by different depths according to the landslide area, and they can provide preliminary results for sediment budget planning in a reservoir basin.展开更多
基金Supported by the Knowledge Innovation Program of the Institute of Geo- graphic Sciences and Natural Resources Research, the Chinese Academy of Sciences （CX10G-E01-02-01, CX10G-E01-08-02, and KZCX1-SW-01- 01A2）, the National Natural Science Foundation of China （30330150）.
文摘The past few decades have seen a resurgence of Interest in biological allometry. Specifically, a number of recent studies has suggested a -4/3 Invariant scaling relationship between mass and density that Is universally valid for tree-dominated communities, regardless of their phyietic affiliation or habitat. In the present study, we test this scaling relationship using a comprehensive forest biomass database, Including 1 266 plots of six blomes and 17 forest types across China. The present study shows that the scaling exponent of the massdensity relationship varies across different tree-dominated communities and habitats. This great variability In the scaling exponent makes any generalization unwarranted. Although Inappropriate regression methods can lead to flawed estimation of the scaling exponent, inconsistency of theoretical framework and empirical patterns may have undermined the validity of previous work.
基金supported by the National Natural Science Foundation of China(project nos.31901086,31988102,31800397)the National Key Research and Development Program of China(2017YFC0503906).
文摘The scaling relationship between leaf area and total mass of plant has important implications for understanding resource allocations in the plant.The model of West,Brown and Enquist(WBE model)considers that a 3/4 scaling exponent of metabolic rate versus total mass to be optimal for each plant and has been confirmed numerous times.Although leaf area is a better proxy of the metabolic rate than leaf mass,few studies have focused on the scaling exponent of leaf area versus total mass and even fewer have discussed the diversification of this scaling exponent across different conditions.Here,I analyzed the scaling exponent of leaf area versus total mass of sample plots across world plants.I found that as the plant grows,it allocates fewer resources to photosynthetic tissues than expected by the WBE model.The results also empirically show that this scaling exponent varies significantly for different plant leaf habit,taxonomic class and geographic region.Therefore,leaf strategy in response to environmental pressure and constraint clearly plays a significant role.
基金supported by the National Natural Science Foundation of China (21838003, 51621002, and 91834301)the Innovation Program of Shanghai Municipal Education Commissionthe Fundamental Research Funds for the Central Universities。
文摘在电解水制氢过程中,为了在低电位下获得超高电流密度,其关键在于打破氧生成反应的标度关系.本文中,我们设计了一种新型异质界面功能化的NiFe(OH)_(x)/Ni_(3)S_(2)电催化剂,成功地规避了析氧反应(OER)的标度关系,使ΔGHOO*-ΔGHO*的差值从3.20 eV降低到2.38 eV.所制备的NiFe(OH)_(x)/Ni_(3)S_(2)电催化剂仅需要310 mV的过电位即可获得2000 mA cm^(-2)的超高电流密度, Tafel斜率仅为20.8 mV dec^(-1).此外,在1000 mA cm^(-2)的电流密度下,稳定运行100小时后无明显的活性损失,该性能优于目前报道的OER催化剂.进一步利用密度泛函理论计算和实验结果揭示了并联催化作用机制,发现多种中间体吸附能均一化能够优化OER反应路径,从而提升超高电流密度下的OER催化性能.本文的研究结果对开发工业级高性能水分解电催化剂具有重要的指导意义.
基金supported by the National Natural Science Foundation of China (31800397)National Key Research and Development Program of China (2017YFC0503900)+2 种基金the TRY initiative on plant traits (http://www.try-db.org)The TRY database is hosted at the Max Planck Institute for Biogeochemistry (Jena, Germany)supported by DIVERSITAS/Future Earth, the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig and EU project BACI (640176)
文摘Leaf nitrogen(N) and phosphorus(P) concentrations are critical for photosynthesis, growth, reproduction and other ecological processes of plants. Previous studies on large-scale biogeographic patterns of leaf N and P stoichiometric relationships were mostly conducted using data pooled across taxa, while family/genus-level analyses are rarely reported. Here, we examined global patterns of family-specific leaf N and P stoichiometry using a global data set of 12,716 paired leaf N and P records which includes 204 families, 1,305 genera, and 3,420 species. After determining the minimum size of samples(i.e., 35 records), we analyzed leaf N and P concentrations, N:P ratios and N^P scaling relationships of plants for 62 families with 11,440 records. The numeric values of leaf N and P stoichiometry varied significantly across families and showed diverse trends along gradients of mean annual temperature(MAT) and mean annual precipitation(MAP). The leaf N and P concentrations and N:P ratios of 62 families ranged from 6.11 to 30.30 mg g–1, 0.27 to 2.17 mg g–1, and 10.20 to 35.40, respectively. Approximately 1/3–1/2 of the families(22–35 of 62) showed a decrease in leaf N and P concentrations and N:P ratios with increasing MAT or MAP, while the remainder either did not show a significant trend or presented the opposite pattern. Family-specific leaf N^P scaling exponents did not converge to a certain empirical value, with a range of 0.307–0.991 for 54 out of 62 families which indicated a significant N^P scaling relationship. Our results for the first time revealed large variation in the family-level leaf N and P stoichiometry of global terrestrial plants and that the stoichiometric relationships for at least one-third of the families were not consistent with the global trends reported previously. The numeric values of the family-specific leaf N and P stoichiometry documented in the current study provide critical synthetic parameters for biogeographic modeling and for further studies on the physiological and ecologica
基金supported by the National Natural Science Foundation of China(No.41572090)National Science and Technology Major Project(No.2016ZX05041004–003)
文摘Palaeodrainage basin,as an important component of the source-to-sink system,contains critical information on provenance and palaeoenvironment.Previous studies indicate that the scaling relationships of source-to-sink system components generally follow power laws,and channel-belt thickness represents a reliable first-order proxy for the drainage area.In this study,a database of borehole cores and geophysical well logs of the Jurassic coal measures from Saishiteng area in the northern Qaidam Basin was used to reconstruct the palaeogeography,and to identify single-story channel-belts.Three palaeochannels,namely,River A,River B and River C,were identified which were persistent throughout the Dameigou and Shimengou Formations during the Middle Jurassic.The mean channel-belt thicknesses of River A,River B and River C in the Dameigou Formation were 9.8 m,8.9 m and 7.9 m,respectively,and those in the Shimengou Formation were 7.4 m,6.2 m and 5.4 m,respectively.We estimate the drainage area of three major rivers by using scaling relationships between drainage area and channel-belt thickness.The drainage areas of River A,River B and River C in the Dameigou Formation were 63.0×10~3 km^2,50.1×10~3 km^2 and 37.7×10~3 km^2,respectively,and those in the Shimengou Formation were 32.3×10~3 km^2,21.2×10~3 km^2 and15.3×10~3 km^2,respectively.The drainage basin lengths of River A,River B and River C in the Dameigou Formation were 300.4 km,239 km and 180.2 km,respectively,and those in the Shimengou Formation were 154.3 km,101.3 km and 73.1 km,respectively.For both the Dameigou and Shimengou Formations,River A showed the largest scale,followed by River B and River C succeedingly,which was mainly determined by the stretch direction of provenance in the southern Qilian Mountains.The variations of channel-belt thickness,drainage area and drainage basin length between Dameigou and Shimengou Formations are the response of source-to-sink system to the transformation from extension to compression depression during the Middle Jurassic in
文摘Landslides produce large quantities of sediment deposits and reduce reservoir life. This study investigated landslides at the Shihmen Reservoir basin in Taiwan that were induced by Typhoon Sinlaku and Typhoon Jangmi in 2008. We formulate scaling relationships between landslide erosion volume and area and conclude that sediment budget can be estimated based on the easier-todetermine landslide erosion area. The methodologies applied for the investigation were geomorphological analysis through 5 m × 5 m digital terrain models(DTMs) of the basin created before and after the landslide events and spatial analysis through a geographic information system. The erosion area and volume of landslides were measured through the subtraction of DTMs produced before and after the events. Statistical analysis revealed that the landslide erosion frequency–magnitude distribution exhibited power-law behaviors with a scaling exponent of 2.15 for the frequency–area distribution and 1.66 for the frequency–volume distribution. This paper proposes different scaling relationships for different moving depths, and landslide erosion volumes were estimated on the basis of depth; thus, landslides of different scales can be distinguished to avoid errors in volume estimation. Two different scaling exponents are proposed: 1.21 for landslide erosions with depths of less than 2 m and 1.01 for landslide erosions with depths of more than 2 m. The proposed scaling relationships are practical for landslide erosion volume estimation by different depths according to the landslide area, and they can provide preliminary results for sediment budget planning in a reservoir basin.
