With development of modern geoscience, particularly development of environmental sciences, the contemporary soil science is undergoing great changes in both research contents and scope. Soil is not onlya certain subst...With development of modern geoscience, particularly development of environmental sciences, the contemporary soil science is undergoing great changes in both research contents and scope. Soil is not onlya certain substance or a certain independent natural historical body but also a spheric layer with peculiarstructure and functions in the earth system. From the viewpoint of the geo-biosphere system of earth, soilscience does deal not only with the soil substances per se but also more importantly with the relationshipsamong soil, the other spheres and the human survival environment in view of the "pedosphere". This is thenew orientation of soil science today and will affect profoundly the studies on the human survival environmentand global changes. To throw more light on this subject, the present paper intends to address the conceptionof pedosphere and its role in global changes. Also addressed are series of environmental issues in China andtheir relations to the global changes. Moreover, research orientation and priorities are indicated, includingexploitation and protection of the soil resources, soil fertility and sustainable agricultural development, construction of the ecological environment, and the material cycling in pedosphere and its relation to globalchanges.展开更多
High altitude and high latitude regions on Earth are experiencing rapid changes in climate, with impacts on polar organisms and the environment. The persistent cold and sometimes inhospitable conditions create unique ...High altitude and high latitude regions on Earth are experiencing rapid changes in climate, with impacts on polar organisms and the environment. The persistent cold and sometimes inhospitable conditions create unique ecosystems and habitats for polar organisms.展开更多
Dear Colleagues, We would like to invite you to submit manuscripts to a special issue of the journal Advances in Polar Science （APS） on ＂Response of Polar Organisms and Natural Environment to Global Changes＂.
Changes in the soil environment induced by major global changes in climate are affecting carbon emissions in cold-temperate coniferous forests.A randomized block experiment simulating warming,rainfall increase and nit...Changes in the soil environment induced by major global changes in climate are affecting carbon emissions in cold-temperate coniferous forests.A randomized block experiment simulating warming,rainfall increase and nitrogen addition in a Larix gmelinii forest was carried out to study the effects on soil carbon,nitrogen,and CO_(2)flux during the thawing,growing,and freezing periods.Our study found that warming(0-2.0℃)increased soil organic carbon(SOC)and total nitrogen(STN),dissolved organic carbon(DOC)and dissolved organic nitrogen(DON),and microbial biomass carbon(MBC)and microbial biomass nitrogen(MBN).Warming played a direct role in regulating soil CO_(2)emissions,stimulated microbial and plant root respiration and soil CO_(2)flux rapidly increased.Rainfall increase initially increased soil carbon and nitrogen,but a 30%increase in mean annual rainfall caused losses of SOC,STN,DOC,and DON,while MBC and MBN accumulated.Soil CO_(2)emissions were regulated by MBC after an increase in rainfall,excess moisture inhibited microbial activity,and soil CO_(2)flux showed a trend of R2(20%rainfall increase)>R1(10%rainfall increase)>CK(control)>R3(30%rainfall increase).The addition of nitrogen increased SOC,STN,DOC,DON,MBC and MBN.Soil CO_(2)flux progressively decreased with nitrogen inputs(2.5,5.0 and 10.0 g m^(-2)a^(-1)),as more N intensified plant-microbe competition.Nitrogen addition indirectly regulated soil CO_(2)emissions by altering SOC and STN,with MBC and MBN acting as secondary regulators.The results highlight the role of cold-temperate coniferous forest soils in predicting carbon-climate feedback in high-latitude forest permafrost regions.展开更多
A review of the year’s international political and security situation In 2010, despite the generally stable international environment, significant changes occurred seen in international relations. This is due
The future global climate changes induced by the increased atmospheric CO2 concentration is receiving much attention from the scientific community as well as the public. Model simulations and palaeoclimatic data studi...The future global climate changes induced by the increased atmospheric CO2 concentration is receiving much attention from the scientific community as well as the public. Model simulations and palaeoclimatic data studies show an evident change in temperature and precipitation over China will occur under conditions of the global warming. Possible scenarios of the future climates are given here for China on the basis of synthesizing model simulations and palaeoclimatic data. Most parts of China will experience an increase in temperature, but the warming may be more remarkable in winter in h1e northern half of the country. Increase in precipitation will be seen in nearly every parts of the eastern China, and it will be larger in North and Northeast China. Impacts of the climate changes on the national tourism are assessed. Regions suitable for tourisin development in terms of climate comfortable index will shift northward. Some scenic spots and toruism facilities will be damaged due to sea level rise and increased rainfall. Some regions will benefit from the dimate change, but the tourism industry as a whole will be negatively affected.展开更多
Two ingressions occurred in the last glacial interstadial (50,00-25,000 a BP) and Holocene optimum (7,500-5,000 a BP) periods in Antercticregion. The grea expansion of Antarcic Ice Sheet appeared at last glacialmaxim...Two ingressions occurred in the last glacial interstadial (50,00-25,000 a BP) and Holocene optimum (7,500-5,000 a BP) periods in Antercticregion. The grea expansion of Antarcic Ice Sheet appeared at last glacialmaximum (18,000 a BP) when Antarctic sea level was 100- 150 m lower thanthat at presat. Three times of glacial advances and rotreas occurred on thefront of Antarctic Ice Shed since 3,000 a BP. All these phenomena werecoordinated with global changes. In the past decades, records from Antercticice-free areas and ice cores testified that mvironmedl and climatic changesin Antarctic region have been coordinated with global changes since latePlelstocene. In the past decades, Antarctic inland was a little warming up andthe fron of the ice shed was slowly melting and ratreating due to the increaseof CO2 content in the atmosphere. The greenhouse effect will cause AntercticIce Sheet (especially on the ice shelves) to be partly melting away, but can notdestroy it. In this case the amplitude of sea level rise caused by the melting ofAntarctic ice will be less than 0.2 m within the coming five decades.展开更多
Soil-emitted N_(2)O contributes to two-thirds of global N_(2)O emissions,and is sensitive to global change.We used DayCent model to simulate major plant-soil N cycling processes under different global change scenarios...Soil-emitted N_(2)O contributes to two-thirds of global N_(2)O emissions,and is sensitive to global change.We used DayCent model to simulate major plant-soil N cycling processes under different global change scenarios in a typical temperate mixed forest in north-eastern China.Simulated scenarios included warming(T),elevated atmospheric CO_(2) concentration([CO_(2)])(C),increased N deposition(N)and precipitation(P),and their full factorial combinations.The responses of plant-soil nitrogen cycling processes including net N mineralization,plant N uptake,gross nitrification,denitrification and soil N_(2)O emission were examined.Concurrent increase of elevated[CO_(2)]and N deposition displayed most strong interactive effects on most fluxes.Using the results from experimental studies for evaluation,simulation uncertainty was highest under elevated[CO_(2)]and increased precipitation among the four global change factors.N deposition had a fundamental impact on soil N cycle and N_(2)O emission in our studied forest.Despite forest soil acting as a N sink for added N,scenarios which included increased N deposition showed higher cumulative soil N_(2)O emissions(summed up from 2001 to 2100).In particular,the scenario which included T,P,and N had the largest cumulative soil N_(2)O emission,which was a 24.4% increase over that under ambient conditions.Our study points to the importance of the interactive effects of global change factors on plant-soil N cycling and the necessity of multi-factor manipulation experiments.展开更多
<p align="justify"> <span style="font-family:Verdana;">Physical concepts based on the Clausius-Clapeyron relation and on the thermodynamics and aerosol characteristics associated with u...<p align="justify"> <span style="font-family:Verdana;">Physical concepts based on the Clausius-Clapeyron relation and on the thermodynamics and aerosol characteristics associated with updrafts, global climate models assuming different parametrizations and lightning-related output variables, and lightning-related data (thunderstorm days) are being used to infer the lightning incidence in a warmer planet, motivated by the global warming observed. In all cases, there are many gaps to be overcome making the lightning response to the global temperature increase still unpredicted. Values from almost 0% (no increase) to 100% have been estimated, being 10% the most common value. While the physical concepts address only part of the problem and the global climate models need to make many simple assumptions, lightning-relate data have strong time and space limitations. In this context, any new evidence should be considered as an important contribution to better understand how will be the lightning incidence in the future. In this article</span></span></span></a><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span><span><span style="font-family:'Minion Pro Capt','serif';"><span style="font-family:Verdana;"> we described new results about the occurrence of thunderstorms from 1850 to 2010 (a period of 160 years) in the city of Rio de Janeiro, in the Southeast of Brazil. During this period thunderstorm days were recorded in the same location, making this time series one of the longest series of this type available worldwide. The data support an increase of 21% in the mean annual thunderstorm days during the period, while surface temperature i</span><span><span style="font-family:Verdana;">ncreased by 0.6</span><span style="text-align:left;widows:2;text-transform:none;background-color:#ffffff;font-style:normal;text-indent:0px;display:inline !important;font-family:Verdana;white-space:normal;orphans:2;float:none;letter-spacing:normal;color:#4f4f4f;font-weight:400;word-spacing:0px;font-variant-ligatures:normal;font-variant-caps:normal;-webkit-text-stroke-width:0px;text-decoration-style:initial;text-decoration-color:initial;">°</span><span style="font-family:Verdana;">C during the period. Considering that the mean annua</span></span><span style="font-family:Verdana;">l number of thunderstorm in the beginning of this period was 29, we found an increase of one thunderstorm day per 0.1</span><span style="text-align:left;widows:2;text-transform:none;background-color:#ffffff;font-style:normal;text-indent:0px;display:inline !important;font-family:Verdana;white-space:normal;orphans:2;float:none;letter-spacing:normal;color:#4f4f4f;font-weight:400;word-spacing:0px;font-variant-ligatures:normal;font-variant-caps:normal;-webkit-text-stroke-width:0px;text-decoration-style:initial;text-decoration-color:initial;">°</span><span style="font-family:Verdana;">C of increase in the surface temperature. Assuming that the number of lightning flashes per thunderstorm remains approximately constant during the period</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> this number corresponds to an increase in the lightning flash rate of approximately 35% per </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="text-align:left;widows:2;text-transform:none;background-color:#ffffff;font-style:normal;text-indent:0px;display:inline !important;font-family:Verdana;white-space:normal;orphans:2;float:none;letter-spacing:normal;color:#4f4f4f;font-weight:400;word-spacing:0px;font-variant-ligatures:normal;font-variant-caps:normal;-webkit-text-stroke-width:0px;text-decoration-style:initial;text-decoration-color:initial;">°</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">C of increase of temperature. In addition, considering that the increase of the global temperature during the period was almost the same that observed in Rio de Janeiro</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> we can conclude that this increase in the lightning flash rate is due to the global warming with no effect of urban activity. Finally, we found that monthly thunderstorm days and monthly mean surface temperature show a linear correlation with a coefficient of 0.9 along the period.</span></span></span> </p>展开更多
The leaf nitrogen(N)to phosphorus(P)ratio(N:P)is a critical indicator of nutrient dynamics and ecosystem function.Investigating temporal variations in leaf N:P can provide valuable insights into how plants adapt to en...The leaf nitrogen(N)to phosphorus(P)ratio(N:P)is a critical indicator of nutrient dynamics and ecosystem function.Investigating temporal variations in leaf N:P can provide valuable insights into how plants adapt to environmental changes and nutrient availability.However,limited research has been conducted on long-term temporal leaf N:P variation over a range of temperature zones.Using long-term monitoring data from the Chinese Ecosystem Research Network(CERN),we investigated temporal changes in leaf N and P stoichiometry for 50 dominant tree species from 10 typical forest sites across temperate and subtropical regions,and identified the underlying mechanisms driving these changes.For both regions combined,leaf P concentration of the 50 dominant tree species decreased(20.6%),whereas leaf N:P increased(52.0%)from 2005 to 2020.Leaf P decreased and leaf N:P increased in 67% and 69% of the tree species,respectively.The leaf N:P increase was primarily driven by the tree species in eastern subtropical forests,where global change factors and soil nutrients explained 68% of leaf N:P variation.The P limitation exhibited by tree species in eastern subtropical forest ecosystems intensified over time,and elevated temperature and CO_(2) levels,coupled with decreased soil available P concentrations,appear to be the main factors driving long-term leaf N:P increases in these forests.Investigating long-term variations in soil nutrients together with global change factors will improve our understanding of the nutrient status of forest ecosystems in the context of global change and will support effective forest ecosystem management.展开更多
1.Drylands face significant challenges under global change Drylands cover approximately 41%of Earth's terrestrial surface and support about 38%of the global population.They comprise a variety of biomes,and provide...1.Drylands face significant challenges under global change Drylands cover approximately 41%of Earth's terrestrial surface and support about 38%of the global population.They comprise a variety of biomes,and provide essential resources and ecosystem services for humans such as mineral resources,food,livestock products,sand stabilization,and soil and water conservation(Li et al.,2021).However,drylands are characterized by water limitation,and are highly sensitive to global change(Prăvălie et al.,2016).展开更多
Urbanization radically alters the climatic environment and landscape patterns of urban areas,but its impact on the carbon sequestration capacity of vegetation remains uncertain.Given the limitations of current small-s...Urbanization radically alters the climatic environment and landscape patterns of urban areas,but its impact on the carbon sequestration capacity of vegetation remains uncertain.Given the limitations of current small-scale ground-based in situ experiments,the response of vegetation carbon sequestration capacity to urbanization and the factors influencing it remain unclear at the global scale.Using multisource remote sensing data,we quanti-fied and differentiated the direct and indirect impacts of urbanization on the carbon sequestration capacity of vegetation in 508 large urban areas globally from 2000 to 2020.The results revealed that the direct impacts of urbanization were generally negative.However,446 cities experienced an indirect enhancement in vegetation carbon sequestration capacity during urbanization,averaging 19.6%globally and offsetting 14.7%of the di-rect loss due to urbanization.These positive indirect effects were most pronounced in environments with limited hydrothermal conditions and increased most in densely populated temperate and cold regions.Furthermore,indi-rect impacts were closely related to urbanization intensity,human footprint,and level of urban development.Our study enhances the understanding of how the carbon sequestration capacity of vegetation dynamically responds to changes in the urban environment,which is crucial for improving future urban vegetation management and building sustainable cities.展开更多
Just a few days after the astronomical spectacle of the“seven planets in alignment”on February 28,2025,the weather in many places underwent a dramatic change.In Shanghai,which was still at the beginning of spring(Ma...Just a few days after the astronomical spectacle of the“seven planets in alignment”on February 28,2025,the weather in many places underwent a dramatic change.In Shanghai,which was still at the beginning of spring(March 1),the temperature suddenly soared to 29℃,the temperature of summer,while Shandong was hit by a sudden heavy snowstorm.There are various opinions and no consensus on this inexplicable weather change.For this reason,based on the principle of the role of planets in the luminescence and heat generation of stars,the author of this article reveals the significant impact of the“Seven planets in alignment”on global climate change,and also points out that the melting of polar glaciers and the approach of the moon to the Earth is another important cause of global climate change.Therefore,countermeasures to save the abnormal changes in global climate are proposed.展开更多
The results of the 2022-2025 study conducted for the vulnerability assessment of pastures and for the development of improvement measures on the degraded land sections in the arid and semi-arid provinces of the Caucas...The results of the 2022-2025 study conducted for the vulnerability assessment of pastures and for the development of improvement measures on the degraded land sections in the arid and semi-arid provinces of the Caucasus under the global climate change conditions are introduced in the current article.The main goal of our scientific work is to study and assess the current ecological and resource state of natural phytocenoses,pastures and hayfields in the arid and semi-arid landscapes under climate change.The paper presents the results of determining the areas and levels of degradation of the natural biogeocenoses and biogeocenoses of the pastures and hayfields in the mountain and highland landscapes.The results were obtained using remote sensing,field and laboratory studies and analyses.The conducted studies have revealed that along 34,174.5 ha pasture and 1342.0 meadows areas of the pastures at the Areni,Yeghegis,Yeghegnadzor and Vayq consolidated administrative territories situated in the arid and semi-arid zones of the Vayots Dzor Region high degradation was recorded in about 6508 hectares of pasture and 407 hectares of meadows areas,which is related to irregular and uncontrolled economic mismanagement of the local population and global climate change.To improve the ecological condition,accessibility and quality of ecosystem services of the pastures,hayfields and natural meadows,comprehensive restoration bioecological and agrotechnical measures have been proposed.They are aimed at improving the air,water and nutrient regimes of soils,at their bioprotection,as well as at the general increase in area and at improving the economic characteristics of the vegetation cover.Such measures on the ecosystem basis are appropriate in the context of enriching the qualitative composition of plants with useful ecological and economic bioecological characteristics,taking into account the characteristics of landscapes,weather and climatic conditions,and agricultural opportunities.展开更多
One-year-resolved and annually-counted stalagmite multi-proxies （j180, ~13C, and layer width） from Daoguan Cave, Guizhou Province revealed detailed variability regarding the Asian Summer Monsoon （ASM） and local hu...One-year-resolved and annually-counted stalagmite multi-proxies （j180, ~13C, and layer width） from Daoguan Cave, Guizhou Province revealed detailed variability regarding the Asian Summer Monsoon （ASM） and local humidity across Bond events （BE） in the PreboreaL During BEs 8 and 7, 1.5%o enrichments in jlSo values were generally consistent with high- to low-latitude climate changes. In detail, the decadal-scale minor j180 oscillations in BE8 were broadly less than the mean value, in contrast to the significant changes in local soil moisture derived from the j13C values and layer records. In the mid-BE7, jlSo variability was generally above the average level, and higher- amplitude variations were observed in the three proxy indicators. Wavelet analysis on the total jlSo time series and across the specific time windows of BEs 8 and 7 identified periodicities of about 130, 60, and 20-a, respectively. Exceptionally strong in BE7, the 60-a cycle, pervasively observed in instrumental studies, became prominent starting at 11.4 kaBP. Thus, glacial background conditions are important for suppressing the ASM intensity in BE8, while during BE7, tropical hydrological circulations were potentially actively involved. Consequently, climate internal oscillations, analogous to modern conditions, might have occurred in the distant past once the link between the tropical ocean and atmosphere was established as occurs today.展开更多
Deforestation and other Land Use and Land Cover(LULC) changes, driven by variety of physical and anthropogenic factors, have altered the mountainous environment. Mountains around the world including northern and north...Deforestation and other Land Use and Land Cover(LULC) changes, driven by variety of physical and anthropogenic factors, have altered the mountainous environment. Mountains around the world including northern and north western belts of Pakistan are highly sensitive to deforestation and other LULC changes, which have profound impacts on various sectors of bio-physical and socio-economic systems. Assessment of LULC changes has high significance for protection, conservation and monitoring mountainous environment. The present study is an attempt to assess the landscape changes with particular reference to forest cover depletion in Kurram Agency located in the north western mountain belt of Pakistan. For detailed comparative analysis the study area has been divided into three sections, which coincide with the present administrative divisions of the Agency, i.e., Upper,Lower and Central Kurram. Temporal span of this study covers four decades. In this study, land use map of 1970 and land sat satellite imageries of 1987, 2000 and 2014 were used as spatial data sets. The images were processed and classified into six LULC classes through geospatial packages and change detection maps were prepared for each division and time period.Findings of the study reveal two trends in the four major LULC categories. Forest and rangeland have shrunk, on average, by 15% and 7.5% respectively while, bare soil and rocks outcrops have expanded by 89% and agriculture land by 7.2% in Kurram agency.The water bodies and snow cover have minor fluctuation in its land area. Major causes of shrinking greenery is attributed to high influx of Afghan refugees and high energy demand of growing population. However, with outflow of the refugees from Kurram agency the general trend in forest cover has reverted and deforestation rate has slowed down.展开更多
Global climate change is intensifying the impact of slope hazards,particularly rainfall-induced landslide hazards(RILH),on mountain road networks(MRNs).However,effective quantitative models for dynamically assessing M...Global climate change is intensifying the impact of slope hazards,particularly rainfall-induced landslide hazards(RILH),on mountain road networks(MRNs).However,effective quantitative models for dynamically assessing MRNs vulnerability under RILH disturbances are still lacking.To bridge this gap,this study develops a Cascading Failure Model for Rainfall-Induced Landslide Hazard(CFM-RILH).Validation via a case study of the GarzêTibetan Autonomous Prefecture Road Network(GTPRNs)reveals key characteristics of MRNs system vulnerability under RILH disturbances:(1)Under the disturbance effects of RILH,the vulnerability of the MRNs system follows a nonlinear phase transition law that intensifies with increasing disturbance intensity,exhibiting a distinct critical threshold.When the disturbance intensity exceeds this threshold,the system undergoes a global cascading failure phenomenon analogous to an“avalanche.”(2)Under RILH disturbances,the robustness of the MRNs system possesses a distinct safety boundary.Exceeding this boundary not only fails to improve hazard resistance but instead substantially elevates the risk of large-scale cascading failure.(3)Increasing network redundancy may be considered one of the primary engineering measures for enhancing MRNs resilience against such disturbances.Based on these findings,we propose a“Two-Stage Emergency Response and Hierarchical Fortification”strategy specifically to improve the resilience of GTPRNs impacted by RILH.The CFM-RILH model provides an effective tool for assessing road network vulnerability under such hazards.Furthermore,its modeling framework can also inform vulnerability assessment and resilience strategy development for road networks affected by other types of slope hazards.展开更多
To feed the increasing world population, more food needs to be produced from agricultural land systems. Solutions to produce more food with fewer resources while minimizing adverse environmental and ecological consequ...To feed the increasing world population, more food needs to be produced from agricultural land systems. Solutions to produce more food with fewer resources while minimizing adverse environmental and ecological consequences require sustainable agricultural land use practices as supplementary to advanced biotechnology and agronomy. This review paper, from a land system perspective, systematically proposed and analyzed three interactive strategies that could possibly raise future food production under global change. By reviewing the current literatures, we suggest that cropland expansion is less possible amid iferce land competition, and it is likely to do less in increasing food production. Moreover, properly allocating crops in space and time is a practical way to ensure food production. Climate change, dietary shifts, and other socio-economic drivers, which would shape the demand and supply side of food systems, should be taken into consideration during the decision-making on rational land management in respect of sustainable crop choice and allocation. And ifnally, crop-speciifc agricultural intensiifcation would play a bigger role in raising future food production either by increasing the yield per unit area of individual crops or by increasing the number of crops sown on a particular area of land. Yet, only when it is done sustainably is this a much more effective strategy to maximize food production by closing yield and harvest gaps.展开更多
China is now the world’s largest producer and user of industrial fertilizers and manures. Consequently China plays a substantial role in global N cycle dynamics and in man’s disruption of the nitrogen cycle though t...China is now the world’s largest producer and user of industrial fertilizers and manures. Consequently China plays a substantial role in global N cycle dynamics and in man’s disruption of the nitrogen cycle though there are still significant uncertainties about the size and importance of emission and leaching rates. A major cause of China’s global role is the overuse of nitrogen fertilizers, which is most serious with intensive vegetable production where application rates can be up to 50% greater than crop needs, but is also a problem with wheat, rice and maize. China’s overuse of nitrogen fertiliser over the past 10-20 years has resulted in non-point source (NPS) pollution from crop production becoming a major cause of water pollution, and the situation is projected to get worse. In contrast, water pollution from point sources such as intensive livestock production and urban or industrial development is being brought more under control. The consequences for air pollution are equally serious. Emissions of nitrous oxide from fertilizers and manures may be so large that China could be responsible for 25-30% of global emissions of this damaging greenhouse gas and of the global warming resulting from it. The main national and local issues relate particularly to low fertilizer use efficiency and the losses of ammonia and NOx that lead to acid precipitation, and leaching and run-off losses that result in high nitrate levels in groundwater and eutrophication of rivers and lakes. The reasons why farmers overuse nitrogen fertilizer are complex and not fully understood. They involve agro-climate differences between provinces and counties, farming systems and farm income structures. Although there is a wide range of institutional and technological improvements that can greatly reduce this overuse rapid progress in reducing NPS is unlikely.展开更多
Soil organic carbon density and its related characteristics of 41 soil types all over China were analyzed by using data of 745 soil profiles , and size of soil carbon pool was estimated. As a result, area-weighted ave...Soil organic carbon density and its related characteristics of 41 soil types all over China were analyzed by using data of 745 soil profiles , and size of soil carbon pool was estimated. As a result, area-weighted averages of these 41 soil types for bulk density, profile depth, organic carbon content and profile carbon were 1. 24 tC/m3, 86. 2 cm, 3. 04% and 19. 7 kg C/m2 respectively. Total size of soil carbon pool was 185. 68 × 1009tC, which is 29 times of that in terrestrial biomass of China and 12. 6% of global soil carbon pools. Because of its huge carbon pool, soil of China plays an important role in global carbon cycle.展开更多
文摘With development of modern geoscience, particularly development of environmental sciences, the contemporary soil science is undergoing great changes in both research contents and scope. Soil is not onlya certain substance or a certain independent natural historical body but also a spheric layer with peculiarstructure and functions in the earth system. From the viewpoint of the geo-biosphere system of earth, soilscience does deal not only with the soil substances per se but also more importantly with the relationshipsamong soil, the other spheres and the human survival environment in view of the "pedosphere". This is thenew orientation of soil science today and will affect profoundly the studies on the human survival environmentand global changes. To throw more light on this subject, the present paper intends to address the conceptionof pedosphere and its role in global changes. Also addressed are series of environmental issues in China andtheir relations to the global changes. Moreover, research orientation and priorities are indicated, includingexploitation and protection of the soil resources, soil fertility and sustainable agricultural development, construction of the ecological environment, and the material cycling in pedosphere and its relation to globalchanges.
文摘High altitude and high latitude regions on Earth are experiencing rapid changes in climate, with impacts on polar organisms and the environment. The persistent cold and sometimes inhospitable conditions create unique ecosystems and habitats for polar organisms.
文摘Dear Colleagues, We would like to invite you to submit manuscripts to a special issue of the journal Advances in Polar Science （APS） on ＂Response of Polar Organisms and Natural Environment to Global Changes＂.
基金funded by the Science and Technology Programme of Inner Mongolia Autonomous Region(Grant No.:2023YFDZ0026 and 2024KYPT0003)the 2024 Postgraduate Research and Innovation Programme of Inner Mongolia Agricultural University。
文摘Changes in the soil environment induced by major global changes in climate are affecting carbon emissions in cold-temperate coniferous forests.A randomized block experiment simulating warming,rainfall increase and nitrogen addition in a Larix gmelinii forest was carried out to study the effects on soil carbon,nitrogen,and CO_(2)flux during the thawing,growing,and freezing periods.Our study found that warming(0-2.0℃)increased soil organic carbon(SOC)and total nitrogen(STN),dissolved organic carbon(DOC)and dissolved organic nitrogen(DON),and microbial biomass carbon(MBC)and microbial biomass nitrogen(MBN).Warming played a direct role in regulating soil CO_(2)emissions,stimulated microbial and plant root respiration and soil CO_(2)flux rapidly increased.Rainfall increase initially increased soil carbon and nitrogen,but a 30%increase in mean annual rainfall caused losses of SOC,STN,DOC,and DON,while MBC and MBN accumulated.Soil CO_(2)emissions were regulated by MBC after an increase in rainfall,excess moisture inhibited microbial activity,and soil CO_(2)flux showed a trend of R2(20%rainfall increase)>R1(10%rainfall increase)>CK(control)>R3(30%rainfall increase).The addition of nitrogen increased SOC,STN,DOC,DON,MBC and MBN.Soil CO_(2)flux progressively decreased with nitrogen inputs(2.5,5.0 and 10.0 g m^(-2)a^(-1)),as more N intensified plant-microbe competition.Nitrogen addition indirectly regulated soil CO_(2)emissions by altering SOC and STN,with MBC and MBN acting as secondary regulators.The results highlight the role of cold-temperate coniferous forest soils in predicting carbon-climate feedback in high-latitude forest permafrost regions.
文摘A review of the year’s international political and security situation In 2010, despite the generally stable international environment, significant changes occurred seen in international relations. This is due
文摘The future global climate changes induced by the increased atmospheric CO2 concentration is receiving much attention from the scientific community as well as the public. Model simulations and palaeoclimatic data studies show an evident change in temperature and precipitation over China will occur under conditions of the global warming. Possible scenarios of the future climates are given here for China on the basis of synthesizing model simulations and palaeoclimatic data. Most parts of China will experience an increase in temperature, but the warming may be more remarkable in winter in h1e northern half of the country. Increase in precipitation will be seen in nearly every parts of the eastern China, and it will be larger in North and Northeast China. Impacts of the climate changes on the national tourism are assessed. Regions suitable for tourisin development in terms of climate comfortable index will shift northward. Some scenic spots and toruism facilities will be damaged due to sea level rise and increased rainfall. Some regions will benefit from the dimate change, but the tourism industry as a whole will be negatively affected.
文摘Two ingressions occurred in the last glacial interstadial (50,00-25,000 a BP) and Holocene optimum (7,500-5,000 a BP) periods in Antercticregion. The grea expansion of Antarcic Ice Sheet appeared at last glacialmaximum (18,000 a BP) when Antarctic sea level was 100- 150 m lower thanthat at presat. Three times of glacial advances and rotreas occurred on thefront of Antarctic Ice Shed since 3,000 a BP. All these phenomena werecoordinated with global changes. In the past decades, records from Antercticice-free areas and ice cores testified that mvironmedl and climatic changesin Antarctic region have been coordinated with global changes since latePlelstocene. In the past decades, Antarctic inland was a little warming up andthe fron of the ice shed was slowly melting and ratreating due to the increaseof CO2 content in the atmosphere. The greenhouse effect will cause AntercticIce Sheet (especially on the ice shelves) to be partly melting away, but can notdestroy it. In this case the amplitude of sea level rise caused by the melting ofAntarctic ice will be less than 0.2 m within the coming five decades.
基金supported by the National Basic Research Program of China(973 program,2014CB954400)the National Natural Science Foundation of China(41401289).
文摘Soil-emitted N_(2)O contributes to two-thirds of global N_(2)O emissions,and is sensitive to global change.We used DayCent model to simulate major plant-soil N cycling processes under different global change scenarios in a typical temperate mixed forest in north-eastern China.Simulated scenarios included warming(T),elevated atmospheric CO_(2) concentration([CO_(2)])(C),increased N deposition(N)and precipitation(P),and their full factorial combinations.The responses of plant-soil nitrogen cycling processes including net N mineralization,plant N uptake,gross nitrification,denitrification and soil N_(2)O emission were examined.Concurrent increase of elevated[CO_(2)]and N deposition displayed most strong interactive effects on most fluxes.Using the results from experimental studies for evaluation,simulation uncertainty was highest under elevated[CO_(2)]and increased precipitation among the four global change factors.N deposition had a fundamental impact on soil N cycle and N_(2)O emission in our studied forest.Despite forest soil acting as a N sink for added N,scenarios which included increased N deposition showed higher cumulative soil N_(2)O emissions(summed up from 2001 to 2100).In particular,the scenario which included T,P,and N had the largest cumulative soil N_(2)O emission,which was a 24.4% increase over that under ambient conditions.Our study points to the importance of the interactive effects of global change factors on plant-soil N cycling and the necessity of multi-factor manipulation experiments.
文摘<p align="justify"> <span style="font-family:Verdana;">Physical concepts based on the Clausius-Clapeyron relation and on the thermodynamics and aerosol characteristics associated with updrafts, global climate models assuming different parametrizations and lightning-related output variables, and lightning-related data (thunderstorm days) are being used to infer the lightning incidence in a warmer planet, motivated by the global warming observed. In all cases, there are many gaps to be overcome making the lightning response to the global temperature increase still unpredicted. Values from almost 0% (no increase) to 100% have been estimated, being 10% the most common value. While the physical concepts address only part of the problem and the global climate models need to make many simple assumptions, lightning-relate data have strong time and space limitations. In this context, any new evidence should be considered as an important contribution to better understand how will be the lightning incidence in the future. In this article</span></span></span></a><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span><span><span style="font-family:'Minion Pro Capt','serif';"><span style="font-family:Verdana;"> we described new results about the occurrence of thunderstorms from 1850 to 2010 (a period of 160 years) in the city of Rio de Janeiro, in the Southeast of Brazil. During this period thunderstorm days were recorded in the same location, making this time series one of the longest series of this type available worldwide. The data support an increase of 21% in the mean annual thunderstorm days during the period, while surface temperature i</span><span><span style="font-family:Verdana;">ncreased by 0.6</span><span style="text-align:left;widows:2;text-transform:none;background-color:#ffffff;font-style:normal;text-indent:0px;display:inline !important;font-family:Verdana;white-space:normal;orphans:2;float:none;letter-spacing:normal;color:#4f4f4f;font-weight:400;word-spacing:0px;font-variant-ligatures:normal;font-variant-caps:normal;-webkit-text-stroke-width:0px;text-decoration-style:initial;text-decoration-color:initial;">°</span><span style="font-family:Verdana;">C during the period. Considering that the mean annua</span></span><span style="font-family:Verdana;">l number of thunderstorm in the beginning of this period was 29, we found an increase of one thunderstorm day per 0.1</span><span style="text-align:left;widows:2;text-transform:none;background-color:#ffffff;font-style:normal;text-indent:0px;display:inline !important;font-family:Verdana;white-space:normal;orphans:2;float:none;letter-spacing:normal;color:#4f4f4f;font-weight:400;word-spacing:0px;font-variant-ligatures:normal;font-variant-caps:normal;-webkit-text-stroke-width:0px;text-decoration-style:initial;text-decoration-color:initial;">°</span><span style="font-family:Verdana;">C of increase in the surface temperature. Assuming that the number of lightning flashes per thunderstorm remains approximately constant during the period</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> this number corresponds to an increase in the lightning flash rate of approximately 35% per </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="text-align:left;widows:2;text-transform:none;background-color:#ffffff;font-style:normal;text-indent:0px;display:inline !important;font-family:Verdana;white-space:normal;orphans:2;float:none;letter-spacing:normal;color:#4f4f4f;font-weight:400;word-spacing:0px;font-variant-ligatures:normal;font-variant-caps:normal;-webkit-text-stroke-width:0px;text-decoration-style:initial;text-decoration-color:initial;">°</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">C of increase of temperature. In addition, considering that the increase of the global temperature during the period was almost the same that observed in Rio de Janeiro</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> we can conclude that this increase in the lightning flash rate is due to the global warming with no effect of urban activity. Finally, we found that monthly thunderstorm days and monthly mean surface temperature show a linear correlation with a coefficient of 0.9 along the period.</span></span></span> </p>
基金supported by the National Natural Science Foundation of China(No.42030509)the Special Project on National Science and Technology Basic Resources Investigation of China(No.2021FY100705).
文摘The leaf nitrogen(N)to phosphorus(P)ratio(N:P)is a critical indicator of nutrient dynamics and ecosystem function.Investigating temporal variations in leaf N:P can provide valuable insights into how plants adapt to environmental changes and nutrient availability.However,limited research has been conducted on long-term temporal leaf N:P variation over a range of temperature zones.Using long-term monitoring data from the Chinese Ecosystem Research Network(CERN),we investigated temporal changes in leaf N and P stoichiometry for 50 dominant tree species from 10 typical forest sites across temperate and subtropical regions,and identified the underlying mechanisms driving these changes.For both regions combined,leaf P concentration of the 50 dominant tree species decreased(20.6%),whereas leaf N:P increased(52.0%)from 2005 to 2020.Leaf P decreased and leaf N:P increased in 67% and 69% of the tree species,respectively.The leaf N:P increase was primarily driven by the tree species in eastern subtropical forests,where global change factors and soil nutrients explained 68% of leaf N:P variation.The P limitation exhibited by tree species in eastern subtropical forest ecosystems intensified over time,and elevated temperature and CO_(2) levels,coupled with decreased soil available P concentrations,appear to be the main factors driving long-term leaf N:P increases in these forests.Investigating long-term variations in soil nutrients together with global change factors will improve our understanding of the nutrient status of forest ecosystems in the context of global change and will support effective forest ecosystem management.
基金supported by the 111 projectthe Fundamental Research Funds for the Central Universities of China。
文摘1.Drylands face significant challenges under global change Drylands cover approximately 41%of Earth's terrestrial surface and support about 38%of the global population.They comprise a variety of biomes,and provide essential resources and ecosystem services for humans such as mineral resources,food,livestock products,sand stabilization,and soil and water conservation(Li et al.,2021).However,drylands are characterized by water limitation,and are highly sensitive to global change(Prăvălie et al.,2016).
基金supported by the National Natural Science Foun-dation of China(Grants No.42471118 and 52078440)the Youth Innovation Promotion Association of CAS(Grant No.2021194).
文摘Urbanization radically alters the climatic environment and landscape patterns of urban areas,but its impact on the carbon sequestration capacity of vegetation remains uncertain.Given the limitations of current small-scale ground-based in situ experiments,the response of vegetation carbon sequestration capacity to urbanization and the factors influencing it remain unclear at the global scale.Using multisource remote sensing data,we quanti-fied and differentiated the direct and indirect impacts of urbanization on the carbon sequestration capacity of vegetation in 508 large urban areas globally from 2000 to 2020.The results revealed that the direct impacts of urbanization were generally negative.However,446 cities experienced an indirect enhancement in vegetation carbon sequestration capacity during urbanization,averaging 19.6%globally and offsetting 14.7%of the di-rect loss due to urbanization.These positive indirect effects were most pronounced in environments with limited hydrothermal conditions and increased most in densely populated temperate and cold regions.Furthermore,indi-rect impacts were closely related to urbanization intensity,human footprint,and level of urban development.Our study enhances the understanding of how the carbon sequestration capacity of vegetation dynamically responds to changes in the urban environment,which is crucial for improving future urban vegetation management and building sustainable cities.
文摘Just a few days after the astronomical spectacle of the“seven planets in alignment”on February 28,2025,the weather in many places underwent a dramatic change.In Shanghai,which was still at the beginning of spring(March 1),the temperature suddenly soared to 29℃,the temperature of summer,while Shandong was hit by a sudden heavy snowstorm.There are various opinions and no consensus on this inexplicable weather change.For this reason,based on the principle of the role of planets in the luminescence and heat generation of stars,the author of this article reveals the significant impact of the“Seven planets in alignment”on global climate change,and also points out that the melting of polar glaciers and the approach of the moon to the Earth is another important cause of global climate change.Therefore,countermeasures to save the abnormal changes in global climate are proposed.
基金the framework of the Project 21T-4C045 of the Higher Education and Science Committee(RA)。
文摘The results of the 2022-2025 study conducted for the vulnerability assessment of pastures and for the development of improvement measures on the degraded land sections in the arid and semi-arid provinces of the Caucasus under the global climate change conditions are introduced in the current article.The main goal of our scientific work is to study and assess the current ecological and resource state of natural phytocenoses,pastures and hayfields in the arid and semi-arid landscapes under climate change.The paper presents the results of determining the areas and levels of degradation of the natural biogeocenoses and biogeocenoses of the pastures and hayfields in the mountain and highland landscapes.The results were obtained using remote sensing,field and laboratory studies and analyses.The conducted studies have revealed that along 34,174.5 ha pasture and 1342.0 meadows areas of the pastures at the Areni,Yeghegis,Yeghegnadzor and Vayq consolidated administrative territories situated in the arid and semi-arid zones of the Vayots Dzor Region high degradation was recorded in about 6508 hectares of pasture and 407 hectares of meadows areas,which is related to irregular and uncontrolled economic mismanagement of the local population and global climate change.To improve the ecological condition,accessibility and quality of ecosystem services of the pastures,hayfields and natural meadows,comprehensive restoration bioecological and agrotechnical measures have been proposed.They are aimed at improving the air,water and nutrient regimes of soils,at their bioprotection,as well as at the general increase in area and at improving the economic characteristics of the vegetation cover.Such measures on the ecosystem basis are appropriate in the context of enriching the qualitative composition of plants with useful ecological and economic bioecological characteristics,taking into account the characteristics of landscapes,weather and climatic conditions,and agricultural opportunities.
基金supported by grants of National Key R&D Program of China(No.2016YFA0600401)National Nature Science Foundation of China(No.41672161)+1 种基金Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)(164320H116)Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application,and Key Laboratory of Virtual Geographic Environment(Nanjing Normal University)
文摘One-year-resolved and annually-counted stalagmite multi-proxies （j180, ~13C, and layer width） from Daoguan Cave, Guizhou Province revealed detailed variability regarding the Asian Summer Monsoon （ASM） and local humidity across Bond events （BE） in the PreboreaL During BEs 8 and 7, 1.5%o enrichments in jlSo values were generally consistent with high- to low-latitude climate changes. In detail, the decadal-scale minor j180 oscillations in BE8 were broadly less than the mean value, in contrast to the significant changes in local soil moisture derived from the j13C values and layer records. In the mid-BE7, jlSo variability was generally above the average level, and higher- amplitude variations were observed in the three proxy indicators. Wavelet analysis on the total jlSo time series and across the specific time windows of BEs 8 and 7 identified periodicities of about 130, 60, and 20-a, respectively. Exceptionally strong in BE7, the 60-a cycle, pervasively observed in instrumental studies, became prominent starting at 11.4 kaBP. Thus, glacial background conditions are important for suppressing the ASM intensity in BE8, while during BE7, tropical hydrological circulations were potentially actively involved. Consequently, climate internal oscillations, analogous to modern conditions, might have occurred in the distant past once the link between the tropical ocean and atmosphere was established as occurs today.
文摘Deforestation and other Land Use and Land Cover(LULC) changes, driven by variety of physical and anthropogenic factors, have altered the mountainous environment. Mountains around the world including northern and north western belts of Pakistan are highly sensitive to deforestation and other LULC changes, which have profound impacts on various sectors of bio-physical and socio-economic systems. Assessment of LULC changes has high significance for protection, conservation and monitoring mountainous environment. The present study is an attempt to assess the landscape changes with particular reference to forest cover depletion in Kurram Agency located in the north western mountain belt of Pakistan. For detailed comparative analysis the study area has been divided into three sections, which coincide with the present administrative divisions of the Agency, i.e., Upper,Lower and Central Kurram. Temporal span of this study covers four decades. In this study, land use map of 1970 and land sat satellite imageries of 1987, 2000 and 2014 were used as spatial data sets. The images were processed and classified into six LULC classes through geospatial packages and change detection maps were prepared for each division and time period.Findings of the study reveal two trends in the four major LULC categories. Forest and rangeland have shrunk, on average, by 15% and 7.5% respectively while, bare soil and rocks outcrops have expanded by 89% and agriculture land by 7.2% in Kurram agency.The water bodies and snow cover have minor fluctuation in its land area. Major causes of shrinking greenery is attributed to high influx of Afghan refugees and high energy demand of growing population. However, with outflow of the refugees from Kurram agency the general trend in forest cover has reverted and deforestation rate has slowed down.
基金financially supported by the National Key R&D Program of China(2024YFE0111900)The National Natural Science Foundation of China(U2468214,52378370,52278372)+1 种基金The National Ten Thousand Talent Program for Young Top-notch Talents(2022QB04978)The Science and Technology Program of Hebei Province(2023HBQZYCSB004)。
文摘Global climate change is intensifying the impact of slope hazards,particularly rainfall-induced landslide hazards(RILH),on mountain road networks(MRNs).However,effective quantitative models for dynamically assessing MRNs vulnerability under RILH disturbances are still lacking.To bridge this gap,this study develops a Cascading Failure Model for Rainfall-Induced Landslide Hazard(CFM-RILH).Validation via a case study of the GarzêTibetan Autonomous Prefecture Road Network(GTPRNs)reveals key characteristics of MRNs system vulnerability under RILH disturbances:(1)Under the disturbance effects of RILH,the vulnerability of the MRNs system follows a nonlinear phase transition law that intensifies with increasing disturbance intensity,exhibiting a distinct critical threshold.When the disturbance intensity exceeds this threshold,the system undergoes a global cascading failure phenomenon analogous to an“avalanche.”(2)Under RILH disturbances,the robustness of the MRNs system possesses a distinct safety boundary.Exceeding this boundary not only fails to improve hazard resistance but instead substantially elevates the risk of large-scale cascading failure.(3)Increasing network redundancy may be considered one of the primary engineering measures for enhancing MRNs resilience against such disturbances.Based on these findings,we propose a“Two-Stage Emergency Response and Hierarchical Fortification”strategy specifically to improve the resilience of GTPRNs impacted by RILH.The CFM-RILH model provides an effective tool for assessing road network vulnerability under such hazards.Furthermore,its modeling framework can also inform vulnerability assessment and resilience strategy development for road networks affected by other types of slope hazards.
基金supported and financed by the National Basic Research Program of China(973 Program,2010CB951504)the National Natural Science Foundation of China(41271112)the National Non-Profit Institute Research Grant of Chinese Academy of Agricultural Sciences,China(IARRP-2014-2)
文摘To feed the increasing world population, more food needs to be produced from agricultural land systems. Solutions to produce more food with fewer resources while minimizing adverse environmental and ecological consequences require sustainable agricultural land use practices as supplementary to advanced biotechnology and agronomy. This review paper, from a land system perspective, systematically proposed and analyzed three interactive strategies that could possibly raise future food production under global change. By reviewing the current literatures, we suggest that cropland expansion is less possible amid iferce land competition, and it is likely to do less in increasing food production. Moreover, properly allocating crops in space and time is a practical way to ensure food production. Climate change, dietary shifts, and other socio-economic drivers, which would shape the demand and supply side of food systems, should be taken into consideration during the decision-making on rational land management in respect of sustainable crop choice and allocation. And ifnally, crop-speciifc agricultural intensiifcation would play a bigger role in raising future food production either by increasing the yield per unit area of individual crops or by increasing the number of crops sown on a particular area of land. Yet, only when it is done sustainably is this a much more effective strategy to maximize food production by closing yield and harvest gaps.
基金Project supported by the Canadian International Development Agency, Canada and the Chinese Academy of Sciences,China (No. KZCX2-413).
文摘China is now the world’s largest producer and user of industrial fertilizers and manures. Consequently China plays a substantial role in global N cycle dynamics and in man’s disruption of the nitrogen cycle though there are still significant uncertainties about the size and importance of emission and leaching rates. A major cause of China’s global role is the overuse of nitrogen fertilizers, which is most serious with intensive vegetable production where application rates can be up to 50% greater than crop needs, but is also a problem with wheat, rice and maize. China’s overuse of nitrogen fertiliser over the past 10-20 years has resulted in non-point source (NPS) pollution from crop production becoming a major cause of water pollution, and the situation is projected to get worse. In contrast, water pollution from point sources such as intensive livestock production and urban or industrial development is being brought more under control. The consequences for air pollution are equally serious. Emissions of nitrous oxide from fertilizers and manures may be so large that China could be responsible for 25-30% of global emissions of this damaging greenhouse gas and of the global warming resulting from it. The main national and local issues relate particularly to low fertilizer use efficiency and the losses of ammonia and NOx that lead to acid precipitation, and leaching and run-off losses that result in high nitrate levels in groundwater and eutrophication of rivers and lakes. The reasons why farmers overuse nitrogen fertilizer are complex and not fully understood. They involve agro-climate differences between provinces and counties, farming systems and farm income structures. Although there is a wide range of institutional and technological improvements that can greatly reduce this overuse rapid progress in reducing NPS is unlikely.
文摘Soil organic carbon density and its related characteristics of 41 soil types all over China were analyzed by using data of 745 soil profiles , and size of soil carbon pool was estimated. As a result, area-weighted averages of these 41 soil types for bulk density, profile depth, organic carbon content and profile carbon were 1. 24 tC/m3, 86. 2 cm, 3. 04% and 19. 7 kg C/m2 respectively. Total size of soil carbon pool was 185. 68 × 1009tC, which is 29 times of that in terrestrial biomass of China and 12. 6% of global soil carbon pools. Because of its huge carbon pool, soil of China plays an important role in global carbon cycle.
