The Experts below are selected from a list of 71844 Experts worldwide ranked by ideXlab platform
Stephan D Flint - One of the best experts on this subject based on the ideXlab platform.
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linkages between stratospheric ozone uv radiation and climate change and their implications for Terrestrial Ecosystems
Photochemical and Photobiological Sciences, 2019Co-Authors: Janet F Bornman, Carlos L Ballare, Sharon A Robinson, P Barnes, Matthew T Robson, Marcel A K Jansen, Stephan D FlintAbstract:Exposure of plants and animals to ultraviolet-B radiation (UV-B; 280–315 nm) is modified by stratospheric ozone dynamics and climate change. Even though stabilisation and projected recovery of stratospheric ozone is expected to curtail future increases in UV-B radiation at the Earth's surface, on-going changes in climate are increasingly exposing plants and animals to novel combinations of UV-B radiation and other climate change factors (e.g., ultraviolet-A and visible radiation, water availability, temperature and elevated carbon dioxide). Climate change is also shifting vegetation cover, geographic ranges of species, and seasonal timing of development, which further modifies exposure to UV-B radiation. Since our last assessment, there has been increased understanding of the underlying mechanisms by which plants perceive UV-B radiation, eliciting changes in growth, development and tolerances of abiotic and biotic factors. However, major questions remain on how UV-B radiation is interacting with other climate change factors to modify the production and quality of crops, as well as important ecosystem processes such as plant and animal competition, pest–pathogen interactions, and the decomposition of dead plant matter (litter). In addition, stratospheric ozone depletion is directly contributing to climate change in the southern hemisphere, such that Terrestrial Ecosystems in this region are being exposed to altered patterns of precipitation, temperature and fire regimes as well as UV-B radiation. These ozone-driven changes in climate have been implicated in both increases and reductions in the growth, survival and reproduction of plants and animals in Antarctica, South America and New Zealand. In this assessment, we summarise advances in our knowledge of these and other linkages and effects, and identify uncertainties and knowledge gaps that limit our ability to fully evaluate the ecological consequences of these environmental changes on Terrestrial Ecosystems.
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effects of increased solar ultraviolet radiation on Terrestrial Ecosystems
Journal of Photochemistry and Photobiology B-biology, 1998Co-Authors: Martyn M Caldwell, Janet F Bornman, Stephan D Flint, Lars Olof Bjorn, G Kulandaivelu, A H Teramura, Manfred TeviniAbstract:Elevated solar UV-B radiation associated with stratospheric ozone reduction may exert effects on Terrestrial Ecosystems through actions on plants, microbes, and perhaps on some animals. At the ecosystem level, the effects are less well understood than at the molecular and organismal levels. Many of the most important, yet less predictable, consequences will be indirect effects of elevated UV-B acting through changes in the chemical composition and form of plants and through changes in the abiotic environment. These indirect effects include changes in the susceptibility of plants to attack by insects and pathogens in both agricultural and natural Ecosystems; the direction of these changes can result in either a decrease or an increase in susceptibility. Other indirect effects of elevated UV-B include changes in competitive balance of plants and nutrient cycling. The direct UV-B action on plants that results in changes in form or function of plants appears to occur more often through altered gene activity rather than damage. The yield of some crop varieties can be decreased by elevated UV-B, but other varieties are not affected. Plant breeding and genetic engineering efforts should be able to cope with the potential threats to crop productivity due to elevated UV-B. For forest trees, this may be more difficult if effects of elevated UV-B accumulate over several years. All effects of elevated UV-B radiation must be considered in the context of other climate changes such as increased temperature and levels of carbon dioxide, which may alter the UV-B responses, especially for plants. The actions of elevated carbon dioxide and UV-B appear to be largely independent, but interactions occur between changes in UV-B and other factors. Other ecosystem-level consequences of elevated UV-B radiation are emerging and their magnitude and direction will not be easily predicted.
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stratospheric ozone reduction solar uv b radiation and Terrestrial Ecosystems
Climatic Change, 1994Co-Authors: Martyn M Caldwell, Stephan D FlintAbstract:Stratospheric ozone reduction is occurring and will continue to increase in magnitude into the next century. Yet, the consequences for Terrestrial Ecosystems of the increased solar UV-B (280–320 nm) radiation resulting from total column ozone reduction are not understood. Based on studies of higher plant response to UV-B, several possible consequences for Ecosystems include decreased primary production, altered plant species composition, and altered secondary chemistry with implications for herbivory, litter decomposition and biogeochemical cycles. However, like the assessment of increased atmospheric CO2, extrapolation from studies with isolated plants to ecosystem function is very tenuous at best. Very few UV-B studies have dealt with multispecies systems. Most of the UV-B research in the past two decades (since the first suggestions of ozone reduction) has been conducted as short-term experiments in growth chambers and greenhouses where the unnatural spectral balance of radiation can lead to unrealistic conclusions. Technical difficulties in suitable measurement and manipulation of UV-B radiation also complicate the conduct of reliable experiments. This essay surveys and categorizes some 300 papers from the past 20 years on this subject, draws general conclusions from the research and offers some recommendations with respect to ecosystem consequences.
Carlos L Ballare - One of the best experts on this subject based on the ideXlab platform.
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linkages between stratospheric ozone uv radiation and climate change and their implications for Terrestrial Ecosystems
Photochemical and Photobiological Sciences, 2019Co-Authors: Janet F Bornman, Carlos L Ballare, Sharon A Robinson, P Barnes, Matthew T Robson, Marcel A K Jansen, Stephan D FlintAbstract:Exposure of plants and animals to ultraviolet-B radiation (UV-B; 280–315 nm) is modified by stratospheric ozone dynamics and climate change. Even though stabilisation and projected recovery of stratospheric ozone is expected to curtail future increases in UV-B radiation at the Earth's surface, on-going changes in climate are increasingly exposing plants and animals to novel combinations of UV-B radiation and other climate change factors (e.g., ultraviolet-A and visible radiation, water availability, temperature and elevated carbon dioxide). Climate change is also shifting vegetation cover, geographic ranges of species, and seasonal timing of development, which further modifies exposure to UV-B radiation. Since our last assessment, there has been increased understanding of the underlying mechanisms by which plants perceive UV-B radiation, eliciting changes in growth, development and tolerances of abiotic and biotic factors. However, major questions remain on how UV-B radiation is interacting with other climate change factors to modify the production and quality of crops, as well as important ecosystem processes such as plant and animal competition, pest–pathogen interactions, and the decomposition of dead plant matter (litter). In addition, stratospheric ozone depletion is directly contributing to climate change in the southern hemisphere, such that Terrestrial Ecosystems in this region are being exposed to altered patterns of precipitation, temperature and fire regimes as well as UV-B radiation. These ozone-driven changes in climate have been implicated in both increases and reductions in the growth, survival and reproduction of plants and animals in Antarctica, South America and New Zealand. In this assessment, we summarise advances in our knowledge of these and other linkages and effects, and identify uncertainties and knowledge gaps that limit our ability to fully evaluate the ecological consequences of these environmental changes on Terrestrial Ecosystems.
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Photodegradation alleviates the lignin bottleneck for carbon turnover in Terrestrial Ecosystems
Proceedings of the National Academy of Sciences, 2016Co-Authors: Amy T Austin, M. Soledad Méndez, Carlos L BallareAbstract:A mechanistic understanding of the controls on carbon storage and losses is essential for our capacity to predict and mitigate human impacts on the global carbon cycle. Plant litter decomposition is an important first step for carbon and nutrient turnover, and litter inputs and losses are essential in determining soil organic matter pools and the carbon balance in Terrestrial Ecosystems. Photodegradation, the photochemical mineralization of organic matter, has been recently identified as a mechanism for previously unexplained high rates of litter mass loss in arid lands; however, the global significance of this process as a control on carbon cycling in Terrestrial Ecosystems is not known. Here we show that, across a wide range of plant species, photodegradation enhanced subsequent biotic degradation of leaf litter. Moreover, we demonstrate that the mechanism for this enhancement involves increased accessibility to plant litter carbohydrates for microbial enzymes. Photodegradation of plant litter, driven by UV radiation, and especially visible (blue-green) light, reduced the structural and chemical bottleneck imposed by lignin in secondary cell walls. In leaf litter from woody species, specific interactions with UV radiation obscured facilitative effects of solar radiation on biotic decomposition. The generalized effect of sunlight exposure on subsequent microbial activity, mediated by increased accessibility to cell wall polysaccharides, suggests that photodegradation is quantitatively important in determining rates of mass loss, nutrient release, and the carbon balance in a broad range of Terrestrial Ecosystems.
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effects of solar ultraviolet radiation on Terrestrial Ecosystems patterns mechanisms and interactions with climate change
Photochemical and Photobiological Sciences, 2011Co-Authors: Carlos L Ballare, Martyn M Caldwell, Stephen D Flint, Sharon A Robinson, Janet F BornmanAbstract:Ultraviolet radiation (UV) is a minor fraction of the solar spectrum reaching the ground surface. In this assessment we summarize the results of previous work on the effects of the UV-B component (280-315 nm) on Terrestrial Ecosystems, and draw attention to important knowledge gaps in our understanding of the interactive effects of UV radiation and climate change. We highlight the following points: (i) The effects of UV-B on the growth of Terrestrial plants are relatively small and, because the Montreal Protocol has been successful in limiting ozone depletion, the reduction in plant growth caused by increased UV-B radiation in areas affected by ozone decline since 1980 is unlikely to have exceeded 6%. (ii) Solar UV-B radiation has large direct and indirect (plant-mediated) effects on canopy arthropods and microorganisms. Therefore, trophic interactions (herbivory, decomposition) in Terrestrial Ecosystems appear to be sensitive to variations in UV-B irradiance. (iii) Future variations in UV radiation resulting from changes in climate and land-use may have more important consequences on Terrestrial Ecosystems than the changes in UV caused by ozone depletion. This is because the resulting changes in UV radiation may affect a greater range of Ecosystems, and will not be restricted solely to the UV-B component. (iv) Several ecosystem processes that are not particularly sensitive to UV-B radiation can be strongly affected by UV-A (315-400 nm) radiation. One example is the physical degradation of plant litter. Increased photodegradation (in response to reduced cloudiness or canopy cover) will lead to increased carbon release to the atmosphere via direct and indirect mechanisms.
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dual role of lignin in plant litter decomposition in Terrestrial Ecosystems
Proceedings of the National Academy of Sciences of the United States of America, 2010Co-Authors: Amy T Austin, Carlos L BallareAbstract:Plant litter decomposition is a critical step in the formation of soil organic matter, the mineralization of organic nutrients, and the carbon balance in Terrestrial Ecosystems. Biotic decomposition in mesic Ecosystems is generally negatively correlated with the concentration of lignin, a group of complex aromatic polymers present in plant cell walls that is recalcitrant to enzymatic degradation and serves as a structural barrier impeding microbial access to labile carbon compounds. Although photochemical mineralization of carbon has recently been shown to be important in semiarid Ecosystems, litter chemistry controls on photodegradative losses are not understood. We evaluated the importance of litter chemistry on photodegradation of grass litter and cellulose substrates with varying levels of lignin [cellulose-lignin (CL) substrates] under field conditions. Using wavelength-specific light attenuation filters, we found that light-driven mass loss was promoted by both UV and visible radiation. The spectral dependence of photodegradation correlated with the absorption spectrum of lignin but not of cellulose. Field incubations demonstrated that increasing lignin concentration reduced biotic decomposition, as expected, but linearly increased photodegradation. In addition, lignin content in CL substrates consistently decreased in photodegradative incubations. We conclude that lignin has a dual role affecting litter decomposition, depending on the dominant driver (biotic or abiotic) controlling carbon turnover. Under photodegradative conditions, lignin is preferentially degraded because it acts as an effective light-absorbing compound over a wide range of wavelengths. This mechanistic understanding of the role of lignin in plant litter decomposition will allow for more accurate predictions of carbon dynamics in Terrestrial Ecosystems.
Janet F Bornman - One of the best experts on this subject based on the ideXlab platform.
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linkages between stratospheric ozone uv radiation and climate change and their implications for Terrestrial Ecosystems
Photochemical and Photobiological Sciences, 2019Co-Authors: Janet F Bornman, Carlos L Ballare, Sharon A Robinson, P Barnes, Matthew T Robson, Marcel A K Jansen, Stephan D FlintAbstract:Exposure of plants and animals to ultraviolet-B radiation (UV-B; 280–315 nm) is modified by stratospheric ozone dynamics and climate change. Even though stabilisation and projected recovery of stratospheric ozone is expected to curtail future increases in UV-B radiation at the Earth's surface, on-going changes in climate are increasingly exposing plants and animals to novel combinations of UV-B radiation and other climate change factors (e.g., ultraviolet-A and visible radiation, water availability, temperature and elevated carbon dioxide). Climate change is also shifting vegetation cover, geographic ranges of species, and seasonal timing of development, which further modifies exposure to UV-B radiation. Since our last assessment, there has been increased understanding of the underlying mechanisms by which plants perceive UV-B radiation, eliciting changes in growth, development and tolerances of abiotic and biotic factors. However, major questions remain on how UV-B radiation is interacting with other climate change factors to modify the production and quality of crops, as well as important ecosystem processes such as plant and animal competition, pest–pathogen interactions, and the decomposition of dead plant matter (litter). In addition, stratospheric ozone depletion is directly contributing to climate change in the southern hemisphere, such that Terrestrial Ecosystems in this region are being exposed to altered patterns of precipitation, temperature and fire regimes as well as UV-B radiation. These ozone-driven changes in climate have been implicated in both increases and reductions in the growth, survival and reproduction of plants and animals in Antarctica, South America and New Zealand. In this assessment, we summarise advances in our knowledge of these and other linkages and effects, and identify uncertainties and knowledge gaps that limit our ability to fully evaluate the ecological consequences of these environmental changes on Terrestrial Ecosystems.
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effects of solar ultraviolet radiation on Terrestrial Ecosystems patterns mechanisms and interactions with climate change
Photochemical and Photobiological Sciences, 2011Co-Authors: Carlos L Ballare, Martyn M Caldwell, Stephen D Flint, Sharon A Robinson, Janet F BornmanAbstract:Ultraviolet radiation (UV) is a minor fraction of the solar spectrum reaching the ground surface. In this assessment we summarize the results of previous work on the effects of the UV-B component (280-315 nm) on Terrestrial Ecosystems, and draw attention to important knowledge gaps in our understanding of the interactive effects of UV radiation and climate change. We highlight the following points: (i) The effects of UV-B on the growth of Terrestrial plants are relatively small and, because the Montreal Protocol has been successful in limiting ozone depletion, the reduction in plant growth caused by increased UV-B radiation in areas affected by ozone decline since 1980 is unlikely to have exceeded 6%. (ii) Solar UV-B radiation has large direct and indirect (plant-mediated) effects on canopy arthropods and microorganisms. Therefore, trophic interactions (herbivory, decomposition) in Terrestrial Ecosystems appear to be sensitive to variations in UV-B irradiance. (iii) Future variations in UV radiation resulting from changes in climate and land-use may have more important consequences on Terrestrial Ecosystems than the changes in UV caused by ozone depletion. This is because the resulting changes in UV radiation may affect a greater range of Ecosystems, and will not be restricted solely to the UV-B component. (iv) Several ecosystem processes that are not particularly sensitive to UV-B radiation can be strongly affected by UV-A (315-400 nm) radiation. One example is the physical degradation of plant litter. Increased photodegradation (in response to reduced cloudiness or canopy cover) will lead to increased carbon release to the atmosphere via direct and indirect mechanisms.
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effects of increased solar ultraviolet radiation on Terrestrial Ecosystems
Journal of Photochemistry and Photobiology B-biology, 1998Co-Authors: Martyn M Caldwell, Janet F Bornman, Stephan D Flint, Lars Olof Bjorn, G Kulandaivelu, A H Teramura, Manfred TeviniAbstract:Elevated solar UV-B radiation associated with stratospheric ozone reduction may exert effects on Terrestrial Ecosystems through actions on plants, microbes, and perhaps on some animals. At the ecosystem level, the effects are less well understood than at the molecular and organismal levels. Many of the most important, yet less predictable, consequences will be indirect effects of elevated UV-B acting through changes in the chemical composition and form of plants and through changes in the abiotic environment. These indirect effects include changes in the susceptibility of plants to attack by insects and pathogens in both agricultural and natural Ecosystems; the direction of these changes can result in either a decrease or an increase in susceptibility. Other indirect effects of elevated UV-B include changes in competitive balance of plants and nutrient cycling. The direct UV-B action on plants that results in changes in form or function of plants appears to occur more often through altered gene activity rather than damage. The yield of some crop varieties can be decreased by elevated UV-B, but other varieties are not affected. Plant breeding and genetic engineering efforts should be able to cope with the potential threats to crop productivity due to elevated UV-B. For forest trees, this may be more difficult if effects of elevated UV-B accumulate over several years. All effects of elevated UV-B radiation must be considered in the context of other climate changes such as increased temperature and levels of carbon dioxide, which may alter the UV-B responses, especially for plants. The actions of elevated carbon dioxide and UV-B appear to be largely independent, but interactions occur between changes in UV-B and other factors. Other ecosystem-level consequences of elevated UV-B radiation are emerging and their magnitude and direction will not be easily predicted.
Martyn M Caldwell - One of the best experts on this subject based on the ideXlab platform.
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effects of solar ultraviolet radiation on Terrestrial Ecosystems patterns mechanisms and interactions with climate change
Photochemical and Photobiological Sciences, 2011Co-Authors: Carlos L Ballare, Martyn M Caldwell, Stephen D Flint, Sharon A Robinson, Janet F BornmanAbstract:Ultraviolet radiation (UV) is a minor fraction of the solar spectrum reaching the ground surface. In this assessment we summarize the results of previous work on the effects of the UV-B component (280-315 nm) on Terrestrial Ecosystems, and draw attention to important knowledge gaps in our understanding of the interactive effects of UV radiation and climate change. We highlight the following points: (i) The effects of UV-B on the growth of Terrestrial plants are relatively small and, because the Montreal Protocol has been successful in limiting ozone depletion, the reduction in plant growth caused by increased UV-B radiation in areas affected by ozone decline since 1980 is unlikely to have exceeded 6%. (ii) Solar UV-B radiation has large direct and indirect (plant-mediated) effects on canopy arthropods and microorganisms. Therefore, trophic interactions (herbivory, decomposition) in Terrestrial Ecosystems appear to be sensitive to variations in UV-B irradiance. (iii) Future variations in UV radiation resulting from changes in climate and land-use may have more important consequences on Terrestrial Ecosystems than the changes in UV caused by ozone depletion. This is because the resulting changes in UV radiation may affect a greater range of Ecosystems, and will not be restricted solely to the UV-B component. (iv) Several ecosystem processes that are not particularly sensitive to UV-B radiation can be strongly affected by UV-A (315-400 nm) radiation. One example is the physical degradation of plant litter. Increased photodegradation (in response to reduced cloudiness or canopy cover) will lead to increased carbon release to the atmosphere via direct and indirect mechanisms.
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effects of increased solar ultraviolet radiation on Terrestrial Ecosystems
Journal of Photochemistry and Photobiology B-biology, 1998Co-Authors: Martyn M Caldwell, Janet F Bornman, Stephan D Flint, Lars Olof Bjorn, G Kulandaivelu, A H Teramura, Manfred TeviniAbstract:Elevated solar UV-B radiation associated with stratospheric ozone reduction may exert effects on Terrestrial Ecosystems through actions on plants, microbes, and perhaps on some animals. At the ecosystem level, the effects are less well understood than at the molecular and organismal levels. Many of the most important, yet less predictable, consequences will be indirect effects of elevated UV-B acting through changes in the chemical composition and form of plants and through changes in the abiotic environment. These indirect effects include changes in the susceptibility of plants to attack by insects and pathogens in both agricultural and natural Ecosystems; the direction of these changes can result in either a decrease or an increase in susceptibility. Other indirect effects of elevated UV-B include changes in competitive balance of plants and nutrient cycling. The direct UV-B action on plants that results in changes in form or function of plants appears to occur more often through altered gene activity rather than damage. The yield of some crop varieties can be decreased by elevated UV-B, but other varieties are not affected. Plant breeding and genetic engineering efforts should be able to cope with the potential threats to crop productivity due to elevated UV-B. For forest trees, this may be more difficult if effects of elevated UV-B accumulate over several years. All effects of elevated UV-B radiation must be considered in the context of other climate changes such as increased temperature and levels of carbon dioxide, which may alter the UV-B responses, especially for plants. The actions of elevated carbon dioxide and UV-B appear to be largely independent, but interactions occur between changes in UV-B and other factors. Other ecosystem-level consequences of elevated UV-B radiation are emerging and their magnitude and direction will not be easily predicted.
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stratospheric ozone reduction solar uv b radiation and Terrestrial Ecosystems
Climatic Change, 1994Co-Authors: Martyn M Caldwell, Stephan D FlintAbstract:Stratospheric ozone reduction is occurring and will continue to increase in magnitude into the next century. Yet, the consequences for Terrestrial Ecosystems of the increased solar UV-B (280–320 nm) radiation resulting from total column ozone reduction are not understood. Based on studies of higher plant response to UV-B, several possible consequences for Ecosystems include decreased primary production, altered plant species composition, and altered secondary chemistry with implications for herbivory, litter decomposition and biogeochemical cycles. However, like the assessment of increased atmospheric CO2, extrapolation from studies with isolated plants to ecosystem function is very tenuous at best. Very few UV-B studies have dealt with multispecies systems. Most of the UV-B research in the past two decades (since the first suggestions of ozone reduction) has been conducted as short-term experiments in growth chambers and greenhouses where the unnatural spectral balance of radiation can lead to unrealistic conclusions. Technical difficulties in suitable measurement and manipulation of UV-B radiation also complicate the conduct of reliable experiments. This essay surveys and categorizes some 300 papers from the past 20 years on this subject, draws general conclusions from the research and offers some recommendations with respect to ecosystem consequences.
Ian F Woodward - One of the best experts on this subject based on the ideXlab platform.
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net primary and ecosystem production and carbon stocks of Terrestrial Ecosystems and their responses to climate change
Global Change Biology, 1998Co-Authors: Mingkui Cao, Ian F WoodwardAbstract:Evaluating the role of Terrestrial Ecosystems in the global carbon cycle requires a detailed understanding of carbon exchange between vegetation, soil, and the atmosphere. Global climatic change may modify the net carbon balance of Terrestrial Ecosystems, causing feedbacks on atmospheric CO2 and climate. We describe a model for investigating Terrestrial carbon exchange and its response to climatic variation based on the processes of plant photosynthesis, carbon allocation, litter production, and soil organic carbon decomposition. The model is used to produce geographical patterns of net primary production (NPP), carbon stocks in vegetation and soils, and the seasonal variations in net ecosystem production (NEP) under both contemporary and future climates. For contemporary climate, the estimated global NPP is 57.0 Gt C y ‐1 , carbon stocks in vegetation and soils are 640 Gt C and 1358 Gt C, respectively, and NEP varies from ‐0.5 Gt C in October to 1.6 Gt C in July. For a doubled atmospheric CO2 concentration and the corresponding climate, we predict that global NPP will rise to 69.6 Gt C y ‐1 , carbon stocks in vegetation and soils will increase by, respectively, 133 Gt C and 160 Gt C, and the seasonal amplitude of NEP will increase by 76%. A doubling of atmospheric CO2 without climate change may enhance NPP by 25% and result in a substantial increase in carbon stocks in vegetation and soils. Climate change without CO2 elevation will reduce the global NPP and soil carbon stocks, but leads to an increase in vegetation carbon because of a forest extension and NPP enhancement in the north. By combining the effects of CO2 doubling, climate change, and the consequent redistribution of vegetation, we predict a strong enhancement in NPP and carbon stocks of Terrestrial Ecosystems. This study simulates the possible variation in the carbon exchange at equilibrium state. We anticipate to investigate the dynamic responses in the carbon exchange to atmospheric CO2 elevation and climate change in the past and future.
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net primary and ecosystem production and carbon stocks of Terrestrial Ecosystems and their responses to climate change
Global Change Biology, 1998Co-Authors: Ian F WoodwardAbstract:Evaluating the role of Terrestrial Ecosystems in the global carbon cycle requires a detailed understanding of carbon exchange between vegetation, soil, and the atmosphere. Global climatic change may modify the net carbon balance of Terrestrial Ecosystems, causing feedbacks on atmospheric CO2 and climate. We describe a model for investigating Terrestrial carbon exchange and its response to climatic variation based on the processes of plant photosynthesis, carbon allocation, litter production, and soil organic carbon decomposition. The model is used to produce geographical patterns of net primary production (NPP), carbon stocks in vegetation and soils, and the seasonal variations in net ecosystem production (NEP) under both contemporary and future climates. For contemporary climate, the estimated global NPP is 57.0 Gt C y ‐1 , carbon stocks in vegetation and soils are 640 Gt C and 1358 Gt C, respectively, and NEP varies from ‐0.5 Gt C in October to 1.6 Gt C in July. For a doubled atmospheric CO2 concentration and the corresponding climate, we predict that global NPP will rise to 69.6 Gt C y ‐1 , carbon stocks in vegetation and soils will increase by, respectively, 133 Gt C and 160 Gt C, and the seasonal amplitude of NEP will increase by 76%. A doubling of atmospheric CO2 without climate change may enhance NPP by 25% and result in a substantial increase in carbon stocks in vegetation and soils. Climate change without CO2 elevation will reduce the global NPP and soil carbon stocks, but leads to an increase in vegetation carbon because of a forest extension and NPP enhancement in the north. By combining the effects of CO2 doubling, climate change, and the consequent redistribution of vegetation, we predict a strong enhancement in NPP and carbon stocks of Terrestrial Ecosystems. This study simulates the possible variation in the carbon exchange at equilibrium state. We anticipate to investigate the dynamic responses in the carbon exchange to atmospheric CO2 elevation and climate change in the past and future.
