For the estimation of global karst carbon sink,a few conventional methods usually require the parameters that are difficult to measure,resulting in the big cost.Moreover,under the constraints of incomplete and timelin...For the estimation of global karst carbon sink,a few conventional methods usually require the parameters that are difficult to measure,resulting in the big cost.Moreover,under the constraints of incomplete and timeliness issues in the collection of data over a large region,it has remained a challenge for these methods to study global karst carbon sink.Therefore,this paper proposes estimating the global karst carbon sink,and analyzing the suitability of the response surface methodology and the fluctuating variation of karst carbon sink in global karst regions from 1951 to 2050.This paper shows that the proposed method can reduce the time of numerical calculation and is suitable for application in global weathering models;The global karst carbon sink in the future changes not only displays an upward trend but also exposures its fluctuating trend largely.This fluctuation is probably due to global warming.展开更多
As an important component of the global carbon cycle, forest soil organic carbon has a crucial impact on the stability of ecosystems and climate change. As one of the largest carbon pools in terrestrial ecosystems, th...As an important component of the global carbon cycle, forest soil organic carbon has a crucial impact on the stability of ecosystems and climate change. As one of the largest carbon pools in terrestrial ecosystems, the organic carbon stock in forest soils is of great significance for climate change and the health of forest ecosystems. This paper provides a comprehensive review of forest soil organic carbon, discussing its research progress, role, influencing factors, and future trends, with the aim of providing scientific evidence for forest soil carbon management to mitigate global climate change and promote the sustainable development of forest ecosystems.展开更多
Montane volcanic ash soils contain disproportionate amounts of soil organic carbon and thereby play an often underestimated role in the global carbon cycle.Given the central role of Al and Fe in stabilizing organic ma...Montane volcanic ash soils contain disproportionate amounts of soil organic carbon and thereby play an often underestimated role in the global carbon cycle.Given the central role of Al and Fe in stabilizing organic matter in volcanic ash soils,we assessed various extraction methods of Al,Fe,and C fractions from montane volcanic ash soils in northern Ecuador,aiming at elucidating the role of Al and Fe in stabilizing soil organic matter(SOM).We found extractions with cold sodium hydroxide,ammonium oxalate/oxalic acid,sodium pyrophosphate,and sodium tetraborate to be particularly useful.Combination of these methods yielded information about the role of the mineral phase in stabilizing organic matter and the differences in type and degree of complexation of organic matter with Al and Fe in the various horizons and soil profiles.Sodium tetraborate extraction proved the only soft extraction method that yielded simultaneous information about the Al,Fe,and C fractions extracted.It also appeared to differentiate between SOM fractions of different stability.The fractions of copper chloride-and potassium chloride-extractable Al were useful in assessing the total reactive and toxic Al fractions,respectively.The classical subdivision of organic matter into humic acids,fulvic acids,and humin added little useful information.The use of fulvic acids as a proxy for mobile organic matter as done in several model-based approaches seems invalid in the soils studied.展开更多
Northern peatlands store a large amount of carbon and play a significant role in the global carbon cycle. Owing to the presence of waterlogged and anaerobic conditions, peatlands are typically a source of methane (CH4...Northern peatlands store a large amount of carbon and play a significant role in the global carbon cycle. Owing to the presence of waterlogged and anaerobic conditions, peatlands are typically a source of methane (CH4), a very potent greenhouse gas. This paper reviews the key mechanisms of peatland CH4 production, consumption and transport and the major environmental and biotic controls on peatland CH4 emissions. The advantages and disadvantages of micrometeorological and chamber methods in measuring CH4 fluxes from northern peatlands are also discussed. The magnitude of CH4 flux varies considerably among peatland types (bogs and fens) and microtopographic locations (hummocks and hollows). Some anthropogenic activities including forestry, peat harvesting and industrial emission of sulphur dioxide can cause a reduction in CH4 release from northern peatlands. Further research should be conducted to investigate the in fluence of plant growth forms on CH4 flux from northern peatlands, determine the water table threshold at which plant production in peatlands enhances CH4 release, and quantify peatland CH4 exchange at plant community level with a higher temporal resolution using automatic chambers.展开更多
Soil respiration （SR） is the second-largest flux in ecosystem carbon cycling. Due to the large spatio-temporal variability of environmental factors, SR varied among different vegetation types, thereby impeding accur...Soil respiration （SR） is the second-largest flux in ecosystem carbon cycling. Due to the large spatio-temporal variability of environmental factors, SR varied among different vegetation types, thereby impeding accurate estimation of CO2 emissions via SR. However, studies on spatio-temporal variation of SR are still scarce for semi-arid regions of North China. In this study, we conducted 12-month SR measurements in six land-use types, including two secondary forests （Populus tomentosa （PT） and Robinia pseudoacacia （RP））, three artificial plantations （Armeniaca sibirica （AS）, Punica granatum （PG） and Ziziphusjujuba （Z J）） and one natural grassland （GR）, to quantify spatio-temporal variation of SR and distinguish its controlling factors. Results indicated that SR exhibited distinct sea- sonal patterns for the six sites. Soil respiration peaked in August 2012 and bottomed in April 2013. The temporal coefficient of variation （CI0 of SR for the six sites ranged from 76.98% to 94.08%, while the spatial CV of SR ranged from 20.28% to 72.97% across the 12-month measurement. Soil temperature and soil moisture were the major controlling factors of temporal variation of SR in the six sites, while spatial variation in SR was mainly caused by the differences in soil total nitrogen （STN）, soil organic carbon （SOC）, net photosynthesis rate, and fine root biomass. Our results show that the annual average SR and Q10 （temperature sensitivity of soil respira- tion） values tended to decrease from secondary forests and grassland to plantations, indicating that the conversion of natural ecosystems to man-made ecosystems may reduce CO2 emissions and SR temperature sensitivity. Due to the high spatio-temporal variation of SR in our study area, care should be taken when converting secondary forests and grassland to plantations from the point view of accurately quantifying C02 emissions via SR at regional scales.展开更多
In carbon global cycle, the relationship between the terrestrial ecosystem and the atmosphere where there are, among others, gases that contribute to the greenhouse effect, has become object of relevant scientific int...In carbon global cycle, the relationship between the terrestrial ecosystem and the atmosphere where there are, among others, gases that contribute to the greenhouse effect, has become object of relevant scientific interest. The content of organic matter in soil, expressed by its supplies as well as the organic matter degree of stability, are factors that can prevent the soil from acting as a drain and at the same time contribute for it to become a source of those gases. The variations in the way land is used in Brazil are factors responsible for the increase in emission of greenhouse effect gases. Based on these facts, this study was aimed to evaluate the CO2 and CH4 efflux using a gas retention chamber, and to associate these emissions to the organic carbon content in the soil. Two different areas were selected for the study, one in Tijuca Forest National Park, in a forest area, and the other at the Rio de Janeiro Federal Rural University campus. In the latter, the area was stratified in three sub areas according to the vegetation, use and water saturation degree. Samplings were performed during 8 months between 2013 and 2014.展开更多
Accurate understanding of global photosynthetic capacity(i.e.maximum RuBisCO carboxylation rate,Vc,max)variability is critical for improved simulations of terrestrial ecosystem photosynthesis metabolisms and carbon cy...Accurate understanding of global photosynthetic capacity(i.e.maximum RuBisCO carboxylation rate,Vc,max)variability is critical for improved simulations of terrestrial ecosystem photosynthesis metabolisms and carbon cycles with climate change,but a holistic understanding and assessment remains lacking.Here we hypothesized that V_(c,max)was dictated by both factors of temperature-associated enzyme kinetics(capturing instantaneous ecophysiological responses)and the amount of activated RuBisCO(indexed by V_(c,max)standardized at 25℃,V_(c,max25)),and compiled a comprehensive global dataset(n=7339 observations from 428 sites)for hypothesis testing.The photosynthesis data were derived from leaf gas exchange measurements using portable gas exchange systems.We found that a semi-empirical statistical model considering both factors explained 78%of global V_(c,max)variability,followed by 55%explained by enzyme kinetics alone.This statistical model outperformed the current theoretical optimality model for predicting global V_(c,max)variability(67%),primarily due to its poor characterization on global V_(c,max25)variability(3%).Further,we demonstrated that,in addition to climatic variables,belowground resource constraint on photosynthetic machinery built-up that directly structures the biogeography of V_(c,max25)was a key missing mechanism for improving the theoretical modelling of global V_(c,max)variability.These findings improve the mechanistic understanding of global V_(c,max)variability and provide an important basis to benchmark process-based models of terrestrial photosynthesis and carbon cycling under climate change.展开更多
The carbon dynamics in soils is of great importance due to its links to the global carbon cycle.The prediction of the behavior of native soil organic carbon(SOC)and organic amendments via incubation studies and mathem...The carbon dynamics in soils is of great importance due to its links to the global carbon cycle.The prediction of the behavior of native soil organic carbon(SOC)and organic amendments via incubation studies and mathematical modeling may bridge the knowledge gap in understanding complex soil ecosystems.Three alkaline Typic Ustochrepts and one Typic Halustalf with sandy,loamy sand,and clay loam texture,varying in percent SOC of 0.2;S_(1),0.42;S_(2),0.67;S_(3) and 0.82;S_(4) soils,were amended with wheat straw(WS),WS+P,sesbania green manure(GM),and poultry manure(PM)on 0.5%C rate at field capacity(FC)and ponding(P)moisture levels and incubated at 35℃for 1,15,30 and 45 d.Carbon mineralization was determined via the alkali titration method after 1,5,714,21,and 28 d.The SOC and inorganic carbon contents were determined from dried up(50℃)soil samples after 1,15,30,and 45 d of incubation.Carbon from residue mineralization was determined by subtracting the amount ofCO_(2)-C evolved from control soils.The kinetic models;monocomponent first order,two-component first or-der,and modified Gompertz equations were fitted to the carbon mineralization data from native and added carbon.The SOC decomposition was dependent upon soil properties,and moisture,however,added C was relatively independent.The carbon from PM was immobilized in S4.All the models fitted to the data predicted carbon mineralization in a similar range with few exceptions.The residues lead to the OC build-up in fine-textured soils having relatively high OC and cation exchange capacities.Whereas,fast degradation of applied OC in coarse-textured soils leads to faster mineralization and lower build-up from residues.The decline in CaCO_(3) after incubation was higher at FC than in the P moisture regime.展开更多
Global vegetation photosynthesis and productivity have increased substantially since the 1980s,but this trend is heterogeneous in both time and space.Here,we categorize the secular trend in global vegetation greenness...Global vegetation photosynthesis and productivity have increased substantially since the 1980s,but this trend is heterogeneous in both time and space.Here,we categorize the secular trend in global vegetation greenness into sustained greening,sustained browning and greening-to-browning.We found that by 2016,increased global vegetation greenness had begun to level off,with the area of browning increasing in the last decade,reaching 39.0 million km^(2)(35.9%of the world’s vegetated area).This area is larger than the area with sustained increasing growth(27.8 million km^(2),26.4%);thus,12.0%±3.1%(0.019±0.004 NDVI a^(-1))of the previous earlier increase has been offset since 2010(2010–2016,P<0.05).Global gross primary production also leveled off,following the trend in vegetation greenness in time and space.This leveling off was caused by increasing soil water limitations due to the spatial expansion of drought,whose impact dominated over the impacts of temperature and solar radiation.This response of global gross primary production to soil water limitation was not identified by land submodels within Earth system models.Our results provide empirical evidence that global vegetation greenness and primary production are offset by water stress and suggest that as global warming continues,land submodels may overestimate the world’s capacity to take up carbon with global vegetation greening.展开更多
Project No.591.The Early to Middle Palaeozoic Revolution Countries involved:Argentina,Australia,Austria,Belgium,Canada,Czech Republic,Denmark,Estonia,France,Germany,Iran,Italy,Lithuania,New Zealand,Norway,People’s Re...Project No.591.The Early to Middle Palaeozoic Revolution Countries involved:Argentina,Australia,Austria,Belgium,Canada,Czech Republic,Denmark,Estonia,France,Germany,Iran,Italy,Lithuania,New Zealand,Norway,People’s Republic of China,Poland,Portugal,Russia,Saudi Arabia,Spain,Sweden,Turkey,United Kingdom,USA Project leaders:Bradley D.Cramer(USA),ÞivileÞigaitë(Lithuania),Thijs R.A.Vanderbroucke(France),Kathleen Histon(Italy),Renbin Zhan(China),Guillermo L.Albanesi(Argentina),Michael J.Melchin(Canada),Mikael Calner(Sweden)Duration:2011-2015 Contact:Bradley D.Cramer Kansas Geological Survey Department of Geology University of Kansas 1930 Constant Avenue Lawrence,Kansas 66047 USA Tel:+16147461334 Fax:+17858645317 E-mail:cramerbd@gmail.com Website:in process The presence of at least eight major perturbations to the global carbon cycle in roughly 40 million years demonstrates that the Late Ordovician to Early Devonian interval was among the climatically least stable episodes of Earth history.Following the Great Ordovician Biodiversification Event(GOBE)and prior to the Devonian Terrestrial Revolution,this interval represents a unique opportunity to study in detail the cause-andeffect relationships of significant global planetary change within a biologically fully populated ocean-atmosphere-biosphere system but prior to the development of a significant global terrestrial biosphere.展开更多
基金supported by the National Natural Science of China[41961065]the Guangxi Innovative Development Grand Program[GuikeAD19254002 and GuikeAA18242048]+3 种基金the Guangxi Natural Science Foundation for Innovation Research Team[2019GXNSFGA245001]the Guilin Research and Development Plan Program[20190210-2]the National Key Research and Development Program of China[2016YFB0502501]the BaGuiScholars program of Guangxi and the Guangxi Key Laboratory of Spatial Information and Geomatics[19-050-11-12].
文摘For the estimation of global karst carbon sink,a few conventional methods usually require the parameters that are difficult to measure,resulting in the big cost.Moreover,under the constraints of incomplete and timeliness issues in the collection of data over a large region,it has remained a challenge for these methods to study global karst carbon sink.Therefore,this paper proposes estimating the global karst carbon sink,and analyzing the suitability of the response surface methodology and the fluctuating variation of karst carbon sink in global karst regions from 1951 to 2050.This paper shows that the proposed method can reduce the time of numerical calculation and is suitable for application in global weathering models;The global karst carbon sink in the future changes not only displays an upward trend but also exposures its fluctuating trend largely.This fluctuation is probably due to global warming.
文摘As an important component of the global carbon cycle, forest soil organic carbon has a crucial impact on the stability of ecosystems and climate change. As one of the largest carbon pools in terrestrial ecosystems, the organic carbon stock in forest soils is of great significance for climate change and the health of forest ecosystems. This paper provides a comprehensive review of forest soil organic carbon, discussing its research progress, role, influencing factors, and future trends, with the aim of providing scientific evidence for forest soil carbon management to mitigate global climate change and promote the sustainable development of forest ecosystems.
基金Supported by the Netherlands Foundation for the Advancement of Tropical Research (NWO-WOTRO) (Nos.WAN 75-405and WAN 75-406)
文摘Montane volcanic ash soils contain disproportionate amounts of soil organic carbon and thereby play an often underestimated role in the global carbon cycle.Given the central role of Al and Fe in stabilizing organic matter in volcanic ash soils,we assessed various extraction methods of Al,Fe,and C fractions from montane volcanic ash soils in northern Ecuador,aiming at elucidating the role of Al and Fe in stabilizing soil organic matter(SOM).We found extractions with cold sodium hydroxide,ammonium oxalate/oxalic acid,sodium pyrophosphate,and sodium tetraborate to be particularly useful.Combination of these methods yielded information about the role of the mineral phase in stabilizing organic matter and the differences in type and degree of complexation of organic matter with Al and Fe in the various horizons and soil profiles.Sodium tetraborate extraction proved the only soft extraction method that yielded simultaneous information about the Al,Fe,and C fractions extracted.It also appeared to differentiate between SOM fractions of different stability.The fractions of copper chloride-and potassium chloride-extractable Al were useful in assessing the total reactive and toxic Al fractions,respectively.The classical subdivision of organic matter into humic acids,fulvic acids,and humin added little useful information.The use of fulvic acids as a proxy for mobile organic matter as done in several model-based approaches seems invalid in the soils studied.
基金Project supported by the Canadian Carbon Program (Fluxnet-Canada Research Network) funded by the Canadian Foundation for Climate and Atmospheric Sciences (CFCAS)a Natural Sciences and Engineering Research Councilof Canada (NSERC) Discovery Grant to Nigel Roulet
文摘Northern peatlands store a large amount of carbon and play a significant role in the global carbon cycle. Owing to the presence of waterlogged and anaerobic conditions, peatlands are typically a source of methane (CH4), a very potent greenhouse gas. This paper reviews the key mechanisms of peatland CH4 production, consumption and transport and the major environmental and biotic controls on peatland CH4 emissions. The advantages and disadvantages of micrometeorological and chamber methods in measuring CH4 fluxes from northern peatlands are also discussed. The magnitude of CH4 flux varies considerably among peatland types (bogs and fens) and microtopographic locations (hummocks and hollows). Some anthropogenic activities including forestry, peat harvesting and industrial emission of sulphur dioxide can cause a reduction in CH4 release from northern peatlands. Further research should be conducted to investigate the in fluence of plant growth forms on CH4 flux from northern peatlands, determine the water table threshold at which plant production in peatlands enhances CH4 release, and quantify peatland CH4 exchange at plant community level with a higher temporal resolution using automatic chambers.
基金Under the auspices of Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA05060600)National Natural Science Foundation of China(No.51378306)
文摘Soil respiration （SR） is the second-largest flux in ecosystem carbon cycling. Due to the large spatio-temporal variability of environmental factors, SR varied among different vegetation types, thereby impeding accurate estimation of CO2 emissions via SR. However, studies on spatio-temporal variation of SR are still scarce for semi-arid regions of North China. In this study, we conducted 12-month SR measurements in six land-use types, including two secondary forests （Populus tomentosa （PT） and Robinia pseudoacacia （RP））, three artificial plantations （Armeniaca sibirica （AS）, Punica granatum （PG） and Ziziphusjujuba （Z J）） and one natural grassland （GR）, to quantify spatio-temporal variation of SR and distinguish its controlling factors. Results indicated that SR exhibited distinct sea- sonal patterns for the six sites. Soil respiration peaked in August 2012 and bottomed in April 2013. The temporal coefficient of variation （CI0 of SR for the six sites ranged from 76.98% to 94.08%, while the spatial CV of SR ranged from 20.28% to 72.97% across the 12-month measurement. Soil temperature and soil moisture were the major controlling factors of temporal variation of SR in the six sites, while spatial variation in SR was mainly caused by the differences in soil total nitrogen （STN）, soil organic carbon （SOC）, net photosynthesis rate, and fine root biomass. Our results show that the annual average SR and Q10 （temperature sensitivity of soil respira- tion） values tended to decrease from secondary forests and grassland to plantations, indicating that the conversion of natural ecosystems to man-made ecosystems may reduce CO2 emissions and SR temperature sensitivity. Due to the high spatio-temporal variation of SR in our study area, care should be taken when converting secondary forests and grassland to plantations from the point view of accurately quantifying C02 emissions via SR at regional scales.
文摘In carbon global cycle, the relationship between the terrestrial ecosystem and the atmosphere where there are, among others, gases that contribute to the greenhouse effect, has become object of relevant scientific interest. The content of organic matter in soil, expressed by its supplies as well as the organic matter degree of stability, are factors that can prevent the soil from acting as a drain and at the same time contribute for it to become a source of those gases. The variations in the way land is used in Brazil are factors responsible for the increase in emission of greenhouse effect gases. Based on these facts, this study was aimed to evaluate the CO2 and CH4 efflux using a gas retention chamber, and to associate these emissions to the organic carbon content in the soil. Two different areas were selected for the study, one in Tijuca Forest National Park, in a forest area, and the other at the Rio de Janeiro Federal Rural University campus. In the latter, the area was stratified in three sub areas according to the vegetation, use and water saturation degree. Samplings were performed during 8 months between 2013 and 2014.
基金supported by National Natural Science Foundation of China(31922090 and 31901086)Hong Kong Research Grant Council Early Career Scheme(27306020)+4 种基金HKU Seed Fund for Basic Research(201905159005 and 202011159154)supported by the Innovation and Technology Fund(funding support to State Key Laboratories in Hong Kong of Agorobiotechnology)of the HKSAR,Chinasupported by the Carbon Mitigation Initiative of the Princeton Universitysupport from the National Science Foundation(DEB-2045968)Texas Tech University.
文摘Accurate understanding of global photosynthetic capacity(i.e.maximum RuBisCO carboxylation rate,Vc,max)variability is critical for improved simulations of terrestrial ecosystem photosynthesis metabolisms and carbon cycles with climate change,but a holistic understanding and assessment remains lacking.Here we hypothesized that V_(c,max)was dictated by both factors of temperature-associated enzyme kinetics(capturing instantaneous ecophysiological responses)and the amount of activated RuBisCO(indexed by V_(c,max)standardized at 25℃,V_(c,max25)),and compiled a comprehensive global dataset(n=7339 observations from 428 sites)for hypothesis testing.The photosynthesis data were derived from leaf gas exchange measurements using portable gas exchange systems.We found that a semi-empirical statistical model considering both factors explained 78%of global V_(c,max)variability,followed by 55%explained by enzyme kinetics alone.This statistical model outperformed the current theoretical optimality model for predicting global V_(c,max)variability(67%),primarily due to its poor characterization on global V_(c,max25)variability(3%).Further,we demonstrated that,in addition to climatic variables,belowground resource constraint on photosynthetic machinery built-up that directly structures the biogeography of V_(c,max25)was a key missing mechanism for improving the theoretical modelling of global V_(c,max)variability.These findings improve the mechanistic understanding of global V_(c,max)variability and provide an important basis to benchmark process-based models of terrestrial photosynthesis and carbon cycling under climate change.
文摘The carbon dynamics in soils is of great importance due to its links to the global carbon cycle.The prediction of the behavior of native soil organic carbon(SOC)and organic amendments via incubation studies and mathematical modeling may bridge the knowledge gap in understanding complex soil ecosystems.Three alkaline Typic Ustochrepts and one Typic Halustalf with sandy,loamy sand,and clay loam texture,varying in percent SOC of 0.2;S_(1),0.42;S_(2),0.67;S_(3) and 0.82;S_(4) soils,were amended with wheat straw(WS),WS+P,sesbania green manure(GM),and poultry manure(PM)on 0.5%C rate at field capacity(FC)and ponding(P)moisture levels and incubated at 35℃for 1,15,30 and 45 d.Carbon mineralization was determined via the alkali titration method after 1,5,714,21,and 28 d.The SOC and inorganic carbon contents were determined from dried up(50℃)soil samples after 1,15,30,and 45 d of incubation.Carbon from residue mineralization was determined by subtracting the amount ofCO_(2)-C evolved from control soils.The kinetic models;monocomponent first order,two-component first or-der,and modified Gompertz equations were fitted to the carbon mineralization data from native and added carbon.The SOC decomposition was dependent upon soil properties,and moisture,however,added C was relatively independent.The carbon from PM was immobilized in S4.All the models fitted to the data predicted carbon mineralization in a similar range with few exceptions.The residues lead to the OC build-up in fine-textured soils having relatively high OC and cation exchange capacities.Whereas,fast degradation of applied OC in coarse-textured soils leads to faster mineralization and lower build-up from residues.The decline in CaCO_(3) after incubation was higher at FC than in the P moisture regime.
基金the National Key Research and Development Program of China(2017YFA0604700)the National Natural Science Foundation of China(41722104)+3 种基金the Key Research Project of Chinese Academy of Sciences(QYZDY-SSWDQC025 and 2019DC0027)supported by the European Research Council Synergy(ERC-2013-Sy G-610028 IMBALANCE-P)the Spanish Government(CGL2016-79835)the Catalan Government(SGR 2017-1005)。
文摘Global vegetation photosynthesis and productivity have increased substantially since the 1980s,but this trend is heterogeneous in both time and space.Here,we categorize the secular trend in global vegetation greenness into sustained greening,sustained browning and greening-to-browning.We found that by 2016,increased global vegetation greenness had begun to level off,with the area of browning increasing in the last decade,reaching 39.0 million km^(2)(35.9%of the world’s vegetated area).This area is larger than the area with sustained increasing growth(27.8 million km^(2),26.4%);thus,12.0%±3.1%(0.019±0.004 NDVI a^(-1))of the previous earlier increase has been offset since 2010(2010–2016,P<0.05).Global gross primary production also leveled off,following the trend in vegetation greenness in time and space.This leveling off was caused by increasing soil water limitations due to the spatial expansion of drought,whose impact dominated over the impacts of temperature and solar radiation.This response of global gross primary production to soil water limitation was not identified by land submodels within Earth system models.Our results provide empirical evidence that global vegetation greenness and primary production are offset by water stress and suggest that as global warming continues,land submodels may overestimate the world’s capacity to take up carbon with global vegetation greening.
文摘Project No.591.The Early to Middle Palaeozoic Revolution Countries involved:Argentina,Australia,Austria,Belgium,Canada,Czech Republic,Denmark,Estonia,France,Germany,Iran,Italy,Lithuania,New Zealand,Norway,People’s Republic of China,Poland,Portugal,Russia,Saudi Arabia,Spain,Sweden,Turkey,United Kingdom,USA Project leaders:Bradley D.Cramer(USA),ÞivileÞigaitë(Lithuania),Thijs R.A.Vanderbroucke(France),Kathleen Histon(Italy),Renbin Zhan(China),Guillermo L.Albanesi(Argentina),Michael J.Melchin(Canada),Mikael Calner(Sweden)Duration:2011-2015 Contact:Bradley D.Cramer Kansas Geological Survey Department of Geology University of Kansas 1930 Constant Avenue Lawrence,Kansas 66047 USA Tel:+16147461334 Fax:+17858645317 E-mail:cramerbd@gmail.com Website:in process The presence of at least eight major perturbations to the global carbon cycle in roughly 40 million years demonstrates that the Late Ordovician to Early Devonian interval was among the climatically least stable episodes of Earth history.Following the Great Ordovician Biodiversification Event(GOBE)and prior to the Devonian Terrestrial Revolution,this interval represents a unique opportunity to study in detail the cause-andeffect relationships of significant global planetary change within a biologically fully populated ocean-atmosphere-biosphere system but prior to the development of a significant global terrestrial biosphere.
