Biomass and net primary productivity （NPP） are two important parameters in determining ecosystem carbon pool and carbon sequestration. The biomass storage and NPP in desert shrubland of Artemisia ordosica on Ordos P...Biomass and net primary productivity （NPP） are two important parameters in determining ecosystem carbon pool and carbon sequestration. The biomass storage and NPP in desert shrubland of Artemisia ordosica on Ordos Plateau were investigated with method of harvesting standard size shrub in the growing season （June-October） of 2006. Results indicated that above- and belowground biomass of the same size shrubs showed no significant variation in the growing season （p〉0.1）, but annual biomass varied significantly （p〈 0.01）. In the A. ordosica community, shrub biomass storage was 699.76-1246.40 g.m^-2 and annual aboveground NPP was 224.09 g-m^-2·a^-1. Moreover, shrub biomass and NPP were closely related with shrub dimensions （cover and height） and could be well predicted by shrub volume using power regression.展开更多
There is a limited knowledge of spatial heterogeneity in soil nutrients and soil respiration in the semi-arid and arid grasslands of China. This study investigated the spatial differences in soil nutrients and soil re...There is a limited knowledge of spatial heterogeneity in soil nutrients and soil respiration in the semi-arid and arid grasslands of China. This study investigated the spatial differences in soil nutrients and soil respiration among three desertified grasslands and within two shrub-dominated communities on the Ordos Plateau of Inner Mongolia, China in 2006. Both soil organic carbon （SOC） and total nitrogen （TN） were significantly different （P 〈 0.01） among the three desertified grasslands along a degradation gradient. Within the two shrub-dominated communities, the SOC and TN contents decreased with increasing distance from the main stems of the shrub, and this ＂fertile island＂ effect was most pronounced in the surface soil. The total soil respirations during the growing season were 131.26, 95.95, and 118.66 g C m^-2, respectively, for the steppe, shrub, and shrub-perennial grass communities. The coefficient of variability of soil respiration was the highest in the shrub community and lowest in the steppe community. CO2 effiuxes from the soil under the canopy of shrub were significantly higher than those from the soil covered with biological crusts and the bare soil in the interplant spaces in the shrub community. However, soil respiration beneath the shrubs was not different from that of the soil in the inter-shrub of the shrub-perennial grass community. This is probably due to the smaller shrub size. In the two shrub-dominated communities, spatial variability in soil respiration was found to depend on soil water content and C：N ratio.展开更多
The Altaid tectonic collage extends over Central Asia, exposing numerous accretionary orogens that can account for the Palaeozoic continental crust growth. A pluridisciplinary approach, using geochronological, geochem...The Altaid tectonic collage extends over Central Asia, exposing numerous accretionary orogens that can account for the Palaeozoic continental crust growth. A pluridisciplinary approach, using geochronological, geochemical, structural and palaeomagnetic tools was carried out to unravel the architecture and the evolution of West Junggar （Northwestern China）, a segment of the Altaid Collage. A polycyclic geodynamic evolution is inferred and includes： （1） an Early Palaeozoic cycle, characterized by the closure of two oceanic basins bounded by island-arc systems; （2） an Early Devonian subduction jamming resulting in a minor-scale collision documented by thrusting, syntectonic sedimentation and subsequent crutal thinning associ- ated with alkaline magmatism; （3） a Late Palaeozoic cycle, driven by the evolution of two opposite subduction zones devel- oped upon the Early Palaeozoic basement. Detailed structural analysis and paleomagnetic data provide constraints for the late evolution of Junggar in the frame of the development of the Late Palaeozoic Kazakh orocline, which led to oblique subduction and transpression in the West Junggar accretionary complex. Progressive buckling of the Kazakh orocline further resulted in Late Carboniferous to Permian wrench tectonics, and lateral displacement of lithotectonic units. Block rotations that continued after the Late Triassic are due to diachronous intraplate reactivation. This scenario mirrors the Palaeozoic geodynamics of the Altaid Collage. Multiple Early Palaeozoic collisions of intra-oceanic arcs and micro continents have contributed to the formarion of the Kazakhstan Microconrinent. Since the Late Palaeozoic, subductions formed around this microcontinent and the final oblique closure of oceanic domains resulted in the transcurrent collage of Tarim and Siberia cratons. Palaeozoic strike-slip faults were later reactivated during Mesozoic intracontinental tectonics.展开更多
基金National Natural Sciences Foundation of China (Nos. 40501072 and 40673067)the Major State Basic Research Develop-ment Program of China (No. 2002CB 412503)the Knowledge In-novation Program of the Institute of Geographic Sciences and Natural Resources Research,CAS "The effect of human activities on regional envi-ronmental quality, the health risk and the environmental remediation"
文摘Biomass and net primary productivity （NPP） are two important parameters in determining ecosystem carbon pool and carbon sequestration. The biomass storage and NPP in desert shrubland of Artemisia ordosica on Ordos Plateau were investigated with method of harvesting standard size shrub in the growing season （June-October） of 2006. Results indicated that above- and belowground biomass of the same size shrubs showed no significant variation in the growing season （p〉0.1）, but annual biomass varied significantly （p〈 0.01）. In the A. ordosica community, shrub biomass storage was 699.76-1246.40 g.m^-2 and annual aboveground NPP was 224.09 g-m^-2·a^-1. Moreover, shrub biomass and NPP were closely related with shrub dimensions （cover and height） and could be well predicted by shrub volume using power regression.
基金Supported by the National Natural Science Foundation of China(Nos.40730105,40501072 and 40973057)the National"Eleventh Five Years Plan"Key Project on Science and Technology of China(No.2007BAC03A11)
文摘There is a limited knowledge of spatial heterogeneity in soil nutrients and soil respiration in the semi-arid and arid grasslands of China. This study investigated the spatial differences in soil nutrients and soil respiration among three desertified grasslands and within two shrub-dominated communities on the Ordos Plateau of Inner Mongolia, China in 2006. Both soil organic carbon （SOC） and total nitrogen （TN） were significantly different （P 〈 0.01） among the three desertified grasslands along a degradation gradient. Within the two shrub-dominated communities, the SOC and TN contents decreased with increasing distance from the main stems of the shrub, and this ＂fertile island＂ effect was most pronounced in the surface soil. The total soil respirations during the growing season were 131.26, 95.95, and 118.66 g C m^-2, respectively, for the steppe, shrub, and shrub-perennial grass communities. The coefficient of variability of soil respiration was the highest in the shrub community and lowest in the steppe community. CO2 effiuxes from the soil under the canopy of shrub were significantly higher than those from the soil covered with biological crusts and the bare soil in the interplant spaces in the shrub community. However, soil respiration beneath the shrubs was not different from that of the soil in the inter-shrub of the shrub-perennial grass community. This is probably due to the smaller shrub size. In the two shrub-dominated communities, spatial variability in soil respiration was found to depend on soil water content and C：N ratio.
基金the National Basic Research Program of China(Grant Nos.2009CB825008&2007CB411301)Chinese National S&T Major Project(Grant No.2008ZX05008)+1 种基金the project‘‘Paleomagnetic study on the tectonic and paleogeographic evolution of northwest of China’’funded by SINOPECco-sponsored by the National Natural Science Foundation of China(Grant Nos.40821002&40802043)
文摘The Altaid tectonic collage extends over Central Asia, exposing numerous accretionary orogens that can account for the Palaeozoic continental crust growth. A pluridisciplinary approach, using geochronological, geochemical, structural and palaeomagnetic tools was carried out to unravel the architecture and the evolution of West Junggar （Northwestern China）, a segment of the Altaid Collage. A polycyclic geodynamic evolution is inferred and includes： （1） an Early Palaeozoic cycle, characterized by the closure of two oceanic basins bounded by island-arc systems; （2） an Early Devonian subduction jamming resulting in a minor-scale collision documented by thrusting, syntectonic sedimentation and subsequent crutal thinning associ- ated with alkaline magmatism; （3） a Late Palaeozoic cycle, driven by the evolution of two opposite subduction zones devel- oped upon the Early Palaeozoic basement. Detailed structural analysis and paleomagnetic data provide constraints for the late evolution of Junggar in the frame of the development of the Late Palaeozoic Kazakh orocline, which led to oblique subduction and transpression in the West Junggar accretionary complex. Progressive buckling of the Kazakh orocline further resulted in Late Carboniferous to Permian wrench tectonics, and lateral displacement of lithotectonic units. Block rotations that continued after the Late Triassic are due to diachronous intraplate reactivation. This scenario mirrors the Palaeozoic geodynamics of the Altaid Collage. Multiple Early Palaeozoic collisions of intra-oceanic arcs and micro continents have contributed to the formarion of the Kazakhstan Microconrinent. Since the Late Palaeozoic, subductions formed around this microcontinent and the final oblique closure of oceanic domains resulted in the transcurrent collage of Tarim and Siberia cratons. Palaeozoic strike-slip faults were later reactivated during Mesozoic intracontinental tectonics.
