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Articles de revues sur le sujet "Carbon cycle (Biogeochemistry)"

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Mahowald, N., K. Lindsay, D. Rothenberg, S. C. Doney, J. K. Moore, P. Thornton, J. T. Randerson et C. D. Jones. « Desert dust and anthropogenic aerosol interactions in the Community Climate System Model coupled-carbon-climate model ». Biogeosciences Discussions 7, no 5 (1 septembre 2010) : 6617–73. http://dx.doi.org/10.5194/bgd-7-6617-2010.

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Abstract. Coupled-carbon-climate simulations are an essential tool for predicting the impact of human activity onto the climate and biogeochemistry. Here we incorporate prognostic desert dust and anthropogenic aerosols into the CCSM3.1 coupled carbon-climate model and explore the resulting interactions with climate and biogeochemical dynamics through a series of transient anthropogenic simulations (20th and 21st centuries) and sensitivity studies. The inclusion of prognostic aerosols into this model has a small net global cooling effect on climate but does not significantly impact the globally averaged carbon cycle; we argue that this is likely to be because the CCSM3.1 model has a small climate feedback onto the carbon cycle. We propose a mechanism for including desert dust and anthropogenic aerosols into a simple carbon-climate feedback analysis to explain the results of our and previous studies. Inclusion of aerosols has statistically significant impacts on regional climate and biogeochemistry, in particular through the effects on the ocean nitrogen cycle and primary productivity of altered iron inputs from desert dust deposition.
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Mahowald, N., K. Lindsay, D. Rothenberg, S. C. Doney, J. K. Moore, P. Thornton, J. T. Randerson et C. D. Jones. « Desert dust and anthropogenic aerosol interactions in the Community Climate System Model coupled-carbon-climate model ». Biogeosciences 8, no 2 (15 février 2011) : 387–414. http://dx.doi.org/10.5194/bg-8-387-2011.

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Abstract. Coupled-carbon-climate simulations are an essential tool for predicting the impact of human activity onto the climate and biogeochemistry. Here we incorporate prognostic desert dust and anthropogenic aerosols into the CCSM3.1 coupled carbon-climate model and explore the resulting interactions with climate and biogeochemical dynamics through a series of transient anthropogenic simulations (20th and 21st centuries) and sensitivity studies. The inclusion of prognostic aerosols into this model has a small net global cooling effect on climate but does not significantly impact the globally averaged carbon cycle; we argue that this is likely to be because the CCSM3.1 model has a small climate feedback onto the carbon cycle. We propose a mechanism for including desert dust and anthropogenic aerosols into a simple carbon-climate feedback analysis to explain the results of our and previous studies. Inclusion of aerosols has statistically significant impacts on regional climate and biogeochemistry, in particular through the effects on the ocean nitrogen cycle and primary productivity of altered iron inputs from desert dust deposition.
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Rodgers, K. B., O. Aumont, S. E. Mikaloff Fletcher, Y. Plancherel, L. Bopp, C. de Boyer Montégut, D. Iudicone, R. F. Keeling, G. Madec et R. Wanninkhof. « Strong sensitivity of Southern Ocean carbon uptake and nutrient cycling to wind stirring ». Biogeosciences Discussions 10, no 9 (13 septembre 2013) : 15033–76. http://dx.doi.org/10.5194/bgd-10-15033-2013.

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Abstract. Here we test the hypothesis that winds have an important role in determining the rate of exchange of CO2 between the atmosphere and ocean through wind stirring over the Southern Ocean. This is tested with a sensitivity study using an ad hoc parameterization of wind stirring in an ocean carbon cycle model. The objective is to identify the way in which perturbations to the vertical density structure of the planetary boundary in the ocean impacts the carbon cycle and ocean biogeochemistry. Wind stirring leads to reduced uptake of CO2 by the Southern Ocean over the period 2000–2006, with differences of order 0.9 Pg C yr−1 over the region south of 45° S. Wind stirring impacts not only the mean carbon uptake, but also the phasing of the seasonal cycle of carbon and other species associated with ocean biogeochemistry. Enhanced wind stirring delays the seasonal onset of stratification, and this has large impacts on both entrainment and the biological pump. It is also found that there is a strong sensitivity of nutrient concentrations exported in Subantarctic Mode Water (SAMW) to wind stirring. This finds expression not only locally over the Southern Ocean, but also over larger scales through the impact on advected nutrients. In summary, the large sensitivity identified with the ad hoc wind stirring parameterization offers support for the importance of wind stirring for global ocean biogeochemistry, through its impact over the Southern Ocean.
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Hajima, Tomohiro, Michio Watanabe, Akitomo Yamamoto, Hiroaki Tatebe, Maki A. Noguchi, Manabu Abe, Rumi Ohgaito et al. « Development of the MIROC-ES2L Earth system model and the evaluation of biogeochemical processes and feedbacks ». Geoscientific Model Development 13, no 5 (13 mai 2020) : 2197–244. http://dx.doi.org/10.5194/gmd-13-2197-2020.

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Abstract. This article describes the new Earth system model (ESM), the Model for Interdisciplinary Research on Climate, Earth System version 2 for Long-term simulations (MIROC-ES2L), using a state-of-the-art climate model as the physical core. This model embeds a terrestrial biogeochemical component with explicit carbon–nitrogen interaction to account for soil nutrient control on plant growth and the land carbon sink. The model's ocean biogeochemical component is largely updated to simulate the biogeochemical cycles of carbon, nitrogen, phosphorus, iron, and oxygen such that oceanic primary productivity can be controlled by multiple nutrient limitations. The ocean nitrogen cycle is coupled with the land component via river discharge processes, and external inputs of iron from pyrogenic and lithogenic sources are considered. Comparison of a historical simulation with observation studies showed that the model could reproduce the transient global climate change and carbon cycle as well as the observed large-scale spatial patterns of the land carbon cycle and upper-ocean biogeochemistry. The model demonstrated historical human perturbation of the nitrogen cycle through land use and agriculture and simulated the resultant impact on the terrestrial carbon cycle. Sensitivity analyses under preindustrial conditions revealed that the simulated ocean biogeochemistry could be altered regionally (and substantially) by nutrient input from the atmosphere and rivers. Based on an idealized experiment in which CO2 was prescribed to increase at a rate of 1 % yr−1, the transient climate response (TCR) is estimated to be 1.5 K, i.e., approximately 70 % of that from our previous ESM used in the Coupled Model Intercomparison Project Phase 5 (CMIP5). The cumulative airborne fraction (AF) is also reduced by 15 % because of the intensified land carbon sink, which results in an airborne fraction close to the multimodel mean of the CMIP5 ESMs. The transient climate response to cumulative carbon emissions (TCRE) is 1.3 K EgC−1, i.e., slightly smaller than the average of the CMIP5 ESMs, which suggests that “optimistic” future climate projections will be made by the model. This model and the simulation results contribute to CMIP6. The MIROC-ES2L could further improve our understanding of climate–biogeochemical interaction mechanisms, projections of future environmental changes, and exploration of our future options regarding sustainable development by evolving the processes of climate, biogeochemistry, and human activities in a holistic and interactive manner.
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Heinze, M., et T. Ilyina. « Ocean Biogeochemistry in the warm climate of the Late Paleocene ». Climate of the Past Discussions 10, no 2 (28 avril 2014) : 1933–75. http://dx.doi.org/10.5194/cpd-10-1933-2014.

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Abstract. The Late Paleocene is characterized by warm and stable climatic conditions which served as the background climate for the Paleocene-Eocene Thermal Maximum (PETM, ~55 million years ago). With respect to feedback processes in the carbon cycle, the ocean biogeochemical background state is of major importance for projecting the climatic response to a carbon perturbation related to the PETM. Therefore we use the Hamburg Ocean Carbon Cycle model HAMOCC, embedded into the ocean general circulation model of the Max Planck Institute for Meteorology, MPIOM, to constrain the ocean biogeochemistry of the Late Paleocene. We focus on the evaluation of modeled spatial and vertical distributions of the ocean carbon cycle parameters in a long-term warm steady-state ocean, based on a 560 ppm CO2 atmosphere. Model results are discussed in the context of available proxy data and simulations of pre-industrial conditions. Our results illustrate that ocean biogeochemistry is shaped by the warm and sluggish ocean state of the Late Paleocene, which affects the strength and spatial variation of the different carbon pumps. Primary production is only slightly reduced in comparison to present-day; it is intensified along the equator, especially in the Atlantic. This enhances remineralization of organic matter, resulting in strong oxygen minimum zones and CaCO3 dissolution in intermediate waters. We show that an equilibrium CO2 exchange without increasing total alkalinity concentrations above today's values is achieved. Yet, the surface ocean pH and the saturation state with respect to CaCO3 are lower than today. Our results indicate that under such conditions, the surface ocean carbonate chemistry is expected to be more sensitive to a carbon perturbation (i.e. the PETM) due to lower CO32− concentration, whereas the deep ocean calcite sediments would be less vulnerable to dissolution due to the sluggish ocean.
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Heinze, M., et T. Ilyina. « Ocean biogeochemistry in the warm climate of the late Paleocene ». Climate of the Past 11, no 1 (13 janvier 2015) : 63–79. http://dx.doi.org/10.5194/cp-11-63-2015.

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Abstract. The late Paleocene is characterized by warm and stable climatic conditions that served as the background climate for the Paleocene–Eocene Thermal Maximum (PETM, ~55 million years ago). With respect to feedback processes in the carbon cycle, the ocean biogeochemical background state is of major importance for projecting the climatic response to a carbon perturbation related to the PETM. Therefore, we use the Hamburg Ocean Carbon Cycle model (HAMOCC), embedded in the ocean general circulation model of the Max Planck Institute for Meteorology, MPIOM, to constrain the ocean biogeochemistry of the late Paleocene. We focus on the evaluation of modeled spatial and vertical distributions of the ocean carbon cycle parameters in a long-term warm steady-state ocean, based on a 560 ppm CO2 atmosphere. Model results are discussed in the context of available proxy data and simulations of pre-industrial conditions. Our results illustrate that ocean biogeochemistry is shaped by the warm and sluggish ocean state of the late Paleocene. Primary production is slightly reduced in comparison to the present day; it is intensified along the Equator, especially in the Atlantic. This enhances remineralization of organic matter, resulting in strong oxygen minimum zones and CaCO3 dissolution in intermediate waters. We show that an equilibrium CO2 exchange without increasing total alkalinity concentrations above today's values is achieved. However, consistent with the higher atmospheric CO2, the surface ocean pH and the saturation state with respect to CaCO3 are lower than today. Our results indicate that, under such conditions, the surface ocean carbonate chemistry is expected to be more sensitive to a carbon perturbation (i.e., the PETM) due to lower CO32− concentration, whereas the deep ocean calcite sediments would be less vulnerable to dissolution due to the vertically stratified ocean.
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Romanou, A., J. Romanski et W. W. Gregg. « Natural ocean carbon cycle sensitivity to parameterizations of the recycling in a climate model ». Biogeosciences Discussions 10, no 7 (5 juillet 2013) : 11111–53. http://dx.doi.org/10.5194/bgd-10-11111-2013.

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Abstract. Sensitivities of the oceanic biological pump within the GISS climate modeling system are explored here. Results are presented from twin control simulations of the air-sea CO2 gas exchange using two different ocean models coupled to the same atmosphere. The two ocean models (Russell ocean model and Hybrid Coordinate Ocean Model, HYCOM) use different vertical coordinate systems, and therefore different representations of column physics. Both variants of the GISS climate model are coupled to the same ocean biogeochemistry module (the NASA Ocean Biogeochemistry Model, NOBM) which computes prognostic distributions for biotic and abiotic fields that influence the air-sea flux of CO2 and the deep ocean carbon transport and storage. In particular, the model differences due to remineralization rate changes are compared to differences attributed to physical processes modeled differently in the two ocean models such as ventilation, mixing, eddy stirring and vertical advection. The Southern Ocean emerges as a key region where the CO2 flux is as sensitive to biological parameterizations as it is to physical parameterizations. Mixing in the Southern Ocean is shown to be a~good indicator of the magnitude of the biological pump efficiency regardless of physical model choice.
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Butzin, Martin, Ying Ye, Christoph Völker, Özgür Gürses, Judith Hauck et Peter Köhler. « Carbon isotopes in the marine biogeochemistry model FESOM2.1-REcoM3 ». Geoscientific Model Development 17, no 4 (26 février 2024) : 1709–27. http://dx.doi.org/10.5194/gmd-17-1709-2024.

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Abstract. In this paper we describe the implementation of the carbon isotopes 13C and 14C (radiocarbon) into the marine biogeochemistry model REcoM3. The implementation is tested in long-term equilibrium simulations where REcoM3 is coupled with the ocean general circulation model FESOM2.1, applying a low-resolution configuration and idealized climate forcing. Focusing on the carbon-isotopic composition of dissolved inorganic carbon (δ13CDIC and Δ14CDIC), our model results are largely consistent with reconstructions for the pre-anthropogenic period. Our simulations also exhibit discrepancies, e.g. in upwelling regions and the interior of the North Pacific. Some of these differences are due to the limitations of our ocean circulation model setup, which results in a rather shallow meridional overturning circulation. We additionally study the accuracy of two simplified modelling approaches for dissolved inorganic 14C, which are faster (15 % and about a factor of five, respectively) than the complete consideration of the marine radiocarbon cycle. The accuracy of both simplified approaches is better than 5 %, which should be sufficient for most studies of Δ14CDIC.
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Keller, K. M., F. Joos et C. C. Raible. « Time of emergence of trends in ocean biogeochemistry ». Biogeosciences 11, no 13 (9 juillet 2014) : 3647–59. http://dx.doi.org/10.5194/bg-11-3647-2014.

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Abstract. For the detection of climate change, not only the magnitude of a trend signal is of significance. An essential issue is the time period required by the trend to be detectable in the first place. An illustrative measure for this is time of emergence (ToE), that is, the point in time when a signal finally emerges from the background noise of natural variability. We investigate the ToE of trend signals in different biogeochemical and physical surface variables utilizing a multi-model ensemble comprising simulations of 17 Earth system models (ESMs). We find that signals in ocean biogeochemical variables emerge on much shorter timescales than the physical variable sea surface temperature (SST). The ToE patterns of pCO2 and pH are spatially very similar to DIC (dissolved inorganic carbon), yet the trends emerge much faster – after roughly 12 yr for the majority of the global ocean area, compared to between 10 and 30 yr for DIC. ToE of 45–90 yr are even larger for SST. In general, the background noise is of higher importance in determining ToE than the strength of the trend signal. In areas with high natural variability, even strong trends both in the physical climate and carbon cycle system are masked by variability over decadal timescales. In contrast to the trend, natural variability is affected by the seasonal cycle. This has important implications for observations, since it implies that intra-annual variability could question the representativeness of irregularly sampled seasonal measurements for the entire year and, thus, the interpretation of observed trends.
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Rodgers, K. B., O. Aumont, S. E. Mikaloff Fletcher, Y. Plancherel, L. Bopp, C. de Boyer Montégut, D. Iudicone, R. F. Keeling, G. Madec et R. Wanninkhof. « Strong sensitivity of Southern Ocean carbon uptake and nutrient cycling to wind stirring ». Biogeosciences 11, no 15 (1 août 2014) : 4077–98. http://dx.doi.org/10.5194/bg-11-4077-2014.

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Abstract. Here we test the hypothesis that winds have an important role in determining the rate of exchange of CO2 between the atmosphere and ocean through wind stirring over the Southern Ocean. This is tested with a sensitivity study using an ad hoc parameterization of wind stirring in an ocean carbon cycle model, where the objective is to identify the way in which perturbations to the vertical density structure of the planetary boundary in the ocean impacts the carbon cycle and ocean biogeochemistry. Wind stirring leads to reduced uptake of CO2 by the Southern Ocean over the period 2000–2006, with a relative reduction with wind stirring on the order of 0.9 Pg C yr−1 over the region south of 45° S. This impacts not only the mean carbon uptake, but also the phasing of the seasonal cycle of carbon and other ocean biogeochemical tracers. Enhanced wind stirring delays the seasonal onset of stratification, and this has large impacts on both entrainment and the biological pump. It is also found that there is a strong reduction on the order of 25–30% in the concentrations of NO3 exported in Subantarctic Mode Water (SAMW) to wind stirring. This finds expression not only locally over the Southern Ocean, but also over larger scales through the impact on advected nutrients. In summary, the large sensitivity identified with the ad hoc wind stirring parameterization offers support for the importance of wind stirring for global ocean biogeochemistry through its impact over the Southern Ocean.
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Thèses sur le sujet "Carbon cycle (Biogeochemistry)"

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Cordova, Vicente D. « Regional-scale carbon flux estimation using MODIS imagery ». Virtual Press, 2005. http://liblink.bsu.edu/uhtbin/catkey/1325989.

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The National Aeronautics and Space Agency NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) platform carried by Terra and Aqua satellites, is providing systematic measurements summarized in high quality, consistent and well-calibrated satellite images and datasets ranging from reflectance in the visible and near infrared bands to estimates of leaf area index, vegetation indices and biome productivity. The objective of this research was to relate the spectral responses and derived MODIS products of ecosystems, to biogeochemical processes and trends in their physiological variables. When different sources of data were compared, discrepancies between the MODIS variables and the corresponding ground measurements were evident. Uncertainties in the input variables of MODIS products algorithms, effects of cloud cover at the studied pixel, estimation algorithm, and local variation in land cover type are considered as the cause. A simple "continuous field" model based on a physiologically-driven spectral index using two ocean-color bands of MODIS satellite sensor showed great potential to track seasonally changing photosynthetic light use efficiency and stress-induced reduction in net primary productivity of terrestrial vegetation. The model explained 88% of the variability in Flux tower-based daily Net Primary Productivity. Also a high correlation between midday gross CO2 exchange with both daily and 8-day mean gross CO2 exchange, consistent across all the studied vegetation types, was found. Although it may not be possible to estimate 8-day mean Light Use Efficiency reliably from satellite data, Light Use Efficiency models may still be useful for estimation of midday values of gross CO2 exchange which could then be related to longer term means of CO2 exchange. In addition, the MODIS enhanced vegetation index shows a high potential for estimation of ecosystem gross primary production, using respiration values from MODIS surface temperature, providing truly per-pixel estimates.
Department of Natural Resources and Environmental Management
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Halloran, Paul R. « Rapid changes in the global carbon cycle ». Thesis, University of Oxford, 2008. http://ora.ox.ac.uk/objects/uuid:cfb93401-3313-4948-a74b-e7e44a068f15.

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The flux of carbon in to and out of the atmosphere exerts a fundamental control over the Earth's climate. The oceans contain almost two orders of magnitude more carbon than the atmosphere, and consequently, small fluctuations within the oceanic carbon reservoir can have very significant effects on air-sea CO2 exchange, and the climate of the planet. Pelagic carbonates represent a major long-term flux of carbon from the surface ocean to deep-sea sediments. Within sediments, the biologically produced carbonates act as a longterm carbon store, but also as chemical recorders of past surface ocean conditions. Counterintuitively, despite the production and sedimentation of carbonate acting as a CO2 sink, over periods shorter than the mixing-time of the ocean, the pH change associated with calcium carbonate precipitation enriches the surface waters in CO2 and elevates the equilibrium value of gaseous exchange with the atmosphere. Coccolithophores, ubiquitous marine photosynthetic plankton, produce calcium carbonate plates, coccoliths, which account for around one third of all marine calcium carbonate production. Sedimentary coccoliths therefore represent a valuable repository of surface ocean geochemical data, as well as a very significant carbon-cycle flux. This thesis examines how the mass of calcium carbonate produced by coccolithophores has changed in response to rising levels of atmospheric CO2. A -40% increase in average coccolith mass over the last 230 years, paralleling anthropogenic CO2 release, is demonstrated within a high-accumulation rate North Atlantic sediment core. Additionally, a flow-cytometry method is presented, which enables the automatic separation of coccoliths from clay particles in sedimentary samples, representing the first step in a coccolith cleaning procedure, which should ultimately enable down-core measurements of coccolith trace-element/calcium ratios. Complementing this work I describe results from continuous dissolution analysis of cultured coccoliths which allows a first-order evaluation of trace-element partitioning into coccoliths produced by the species Coccoliths pelagicus, and present a conceptual methodology to allow the determination of single-species coccolith chemical data.
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Holmes, Brett. « Mobilization of Metals and Phosphorous from Intact Forest Soil Cores by Dissolved Inorganic Carbon : A Laboratory Column Study ». Fogler Library, University of Maine, 2007. http://www.library.umaine.edu/theses/pdf/HolmesB2007.pdf.

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Trudinger, Catherine Mary. « The carbon cycle over the last 1000 years inferred from inversion of ice core data / ». Full text, 2000. http://www.dar.csiro.au/publications/Trudinger_2001a0.htm.

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Ridgwell, Andy J. « Glacial-interglacial perturbations in the global carbon cycle ». Thesis, University of East Anglia, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365134.

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Kambis, Alexis Demitrios. « A numerical model of the global carbon cycle to predict atmospheric carbon dioxide concentrations ». W&M ScholarWorks, 1995. https://scholarworks.wm.edu/etd/1539616709.

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A numerical model of the global carbon cycle is presented which includes the effects of anthropogenic &CO\sb2& emissions &(CO\sb2& produced from fossil fuel combustion, biomass burning, and deforestation) on the global carbon cycle. The model is validated against measured atmospheric &CO\sb2& concentrations. Future levels of atmospheric &CO\sb2& are then predicted for the following scenarios: (1) Business as Usual (BaU) for the period 1990-2000; (2) Same as (1), but with no biomass burning; (3) Same as (1), but with no fossil fuel combustion; (4) Same as (1), but with a doubled atmospheric &CO\sb2& concentration and a 2 K warmer surface temperature associated with the doubled atmospheric &CO\sb2& concentration. The global model presented here consists of four different modules which are fully coupled with respect to &CO\sb2.& These modules represent carbon cycling by the terrestrial biosphere and the ocean, anthropogenic &CO\sb2& emissions, and atmospheric transport of &CO\sb2.&. The prognostic variable of interest is the atmospheric &CO\sb2& concentration field. The &CO\sb2& concentration field depends on both the sources and sinks of &CO\sb2& as well as the atmospheric circulation. In addition, the sources and sinks vary significantly as a function of both time and geographic location. The model output agrees well with measured data at the equatorial and mid latitudes, but this agreement weakens at higher latitudes. This is due to the less adequate representation of the terrestrial ecosystem models at these latitudes. In the first scenario, the predicted concentration of atmospheric &CO\sb2& is 362 parts per million by volume (ppmv) at the end of the 10 year model run. This establishes a baseline for the next three scenarios, which predict that biomass burning will contribute 3 ppmv of &CO\sb2& to the atmosphere by the year 2000, while fossil fuel combustion will contribute 5 ppmv. The net effect of a 2 K average global warming was to increase the atmospheric &CO\sb2& concentration by approximately 1 ppmv, due to enhanced respiration by the terrestrial biosphere.
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Carozza, David. « Carbon cycle box modeling studies of the Paleocene-Eocene thermal maximum ». Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66818.

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Approximately 55 million years ago, an unprecedented amount of light carbon was abruptly released into the ocean and atmosphere. This event, known as the Paleocene-Eocene thermal maximum (PETM), is documented by large negative carbon isotope excursions in marine and soil carbonates and by global environmental changes. Models have been applied to constrain the amount of carbon released during the PETM. In this study, the Walker-Kasting carbon cycle box model is revisited and, after correcting its carbon isotope equations, it is used to resolve a discrepancy in previous emission estimates. In addition, the atmospheric methane box model of Schmidt-Shindell is coupled to the Walker-Kasting model to explore the role of methane during the PETM. This coupled model is then combined with results from other modeling studies to demonstrate that the PETM may have been caused by the rel ease of approximately 3500 Pg C of thermogenic methane into the Atlantic Ocean.
Il y a environ 55 millions d'années, une quantité sans précédent de carbone a été brusquement libérée dans l'océan et l'atmosphère. Cet événement, désigné de maximum thermique Paléocène-Eocène (PETM), est identifiable par de remarquables excursions négatives de del13C en carbonate marin et sol, et par des bouleversements environnementaux d'échelle globale. Plusieurs modèles ont été utilisés afin d'estimer la quantité de carbone émise durant le PETM. Cette étude reprend le modèle du cycle du carbone de Walker-Kasting, révise ses équations du del13C et l'utilise pour résoudre un désaccord entre des estimés antérieures de l'émission totale. Le modèle du méthane atmosphérique de Schmidt-Shindell est également couplé à celui de Walker-Kasting dans le but d'examiner l'importance du méthane durant le PETM. Finalement, ce modèle couplé, en combinaison avec les résultats d'autres modèles, est implémenté pour démontrer que le PETM aurait pu être engendré par l'émission de 3500 Pg C de méthane thermogénétique à l'océan Atlantique.
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Smith, Joanne Caroline. « Particulate organic carbon mobilisation and export from temperate forested uplands ». Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648250.

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Ferretti, Dominic Francesco. « The development and application of a new high precision GC-IRMS technique for N₂O-free isotopic analysis of astmospheric CO₂ ». [Wellington, New Zealand] : Victoria University of Wellington, 1999. http://catalog.hathitrust.org/api/volumes/oclc/154329143.html.

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Bachman, Sarah. « Elevated atmospheric carbon dioxide and precipitation alter ecosystem carbon fluxes over northern mixed-grass prairie at the prairie heating and CO2 enrichment (PHACE) experiment in Cheyenne, Wyoming, USA ». Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1445355711&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.

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Livres sur le sujet "Carbon cycle (Biogeochemistry)"

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R, Trabalka John, et United States. Dept. of Energy. Office of Basic Energy Sciences. Carbon Dioxide Research Division., dir. Atmospheric carbon dioxide and the global carbon cycle. Washington, D.C : U.S. Dept. of Energy, Office of Energy Research, Office of Basic Energy Sciences, Carbon Dioxide Research Division, 1985.

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1965-, McPherson Brian J., et Sundquist E. T, dir. Carbon sequestration and its role in the global carbon cycle. Washington, DC : American Geophysical Union, 2009.

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Josef, Cihlar, Heimann Martin 1949-, Olson Richard K et Food and Agriculture Organization of the United Nations., dir. Terrestrial carbon observation : The Frascati report on in situ carbon data and information : 5-8 June 2001, Frastcati, Italy. Rome : Food and Agriculture Organization of the United Nations, 2002.

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A, Davidson Eric, et United States. National Aeronautics and Space Administration., dir. Effect of land use change on the carbon cycle in Amazon soils : Final technical report. [Washington, DC : National Aeronautics and Space Administration, 1994.

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Kokuritsu Kankyō Kenkyūjo. Chikyū Kankyō Kenkyū Sentā. Chikyū kankyō kansoku dēta to moderu tōgoka ni yoru tanso junkan hendō haaku no tame no kenkyū rōdo mappu. Ibaraki-ken Tsukuba-shi : Kokuritsu Kankyō Kenkyūjo Chikyū Kankyō Kenkyū Sentā, 2013.

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National Agroforestry Center (U.S.), dir. Working trees for carbon cycle balance. [Lincoln, Neb.] : USDA, National Agroforestry Center, 2000.

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National Agroforestry Center (U.S.), dir. Working trees for carbon cycle balance. [Lincoln, Neb.] : USDA, National Agroforestry Center, 2000.

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8

Ridzon, Leonard. The carbon connection. Kansas City, Mo : Acres U.S.A., 1990.

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Natural Sinks of CO2 (1992 Palmas Del Mar, Puerto Rico). Natural sinks of CO2 : Palmas Del Mar, Puerto Rico, 24-27 February 1992. Dordrecht : Kluwer Academic, 1992.

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Stanley, Dagley, Hagedorn Scott R. 1951-, Hanson Richard S. 1935- et Kunz Daniel A. 1949-, dir. Microbial metabolism and the carbon cycle : A symposium in honor of Stanley Dagley ; edited by Scott R. Hagedorn, Richard S. Hanson, Daniel A. Kunz. Chur, Switzerland : Harwood Academic Publishers, 1988.

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Chapitres de livres sur le sujet "Carbon cycle (Biogeochemistry)"

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Doney, Scott C., Keith Lindsay et J. Keith Moore. « Global Ocean Carbon Cycle Modeling ». Dans Ocean Biogeochemistry, 217–38. Berlin, Heidelberg : Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-642-55844-3_10.

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Boyd, Philip W., et Scott C. Doney. « The Impact of Climate Change and Feedback Processes on the Ocean Carbon Cycle ». Dans Ocean Biogeochemistry, 157–93. Berlin, Heidelberg : Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-642-55844-3_8.

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ACHTERBERG, ERIC P. « chapter 1 Grand Challenges in Marine Biogeochemistry ». Dans Climate Change and the Oceanic Carbon Cycle, 1–14. 3333 Mistwell Crescent, Oakville, ON L6L 0A2, Canada : Apple Academic Press, 2017. http://dx.doi.org/10.1201/9781315207490-2.

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Simoneit, B. R. T. « Hydrothermal Petroleum Generation from Immature Organic Matter-Implications to the Oceanic Carbon Cycle ». Dans Facets of Modern Biogeochemistry, 365–87. Berlin, Heidelberg : Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-73978-1_28.

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Fung, Inez. « Models of Oceanic and Terrestrial Sinks of Anthropogenic CO2 : A Review of the Contemporary Carbon Cycle ». Dans Biogeochemistry of Global Change, 166–89. Boston, MA : Springer US, 1993. http://dx.doi.org/10.1007/978-1-4615-2812-8_9.

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Skjelvan, Ingunn, Are Olsen, Leif G. Anderson, Richard G. J. Bellerby, Eva Falck, Yoshie Kasajima, Caroline Kivimäe et al. « A review of the inorganic carbon cycle of the Nordic Seas and Barents Sea ». Dans The Nordic Seas : An Integrated Perspective Oceanography, Climatology, Biogeochemistry, and Modeling, 157–75. Washington, D. C. : American Geophysical Union, 2005. http://dx.doi.org/10.1029/158gm11.

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Walker, James C. G. « Biogeochemical Cycles of Carbon on a Hierarchy of Time Scales ». Dans Biogeochemistry of Global Change, 3–28. Boston, MA : Springer US, 1993. http://dx.doi.org/10.1007/978-1-4615-2812-8_1.

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Bianchi, Thomas S. « Carbon Cycle ». Dans Biogeochemistry of Estuaries. Oxford University Press, 2006. http://dx.doi.org/10.1093/oso/9780195160826.003.0023.

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Carbon is the key element of life on Earth and exists in more than a million compounds (Holmén, 2000; Berner, 2004). The unique covalent long-chained and aromatic carbon compounds form the basis of organic chemistry and the “roadmap” for understanding life from the cellular to the ecosystem level. The oxidation states of C atoms range from +IV to −IV; methane (CH4) is the most reduced form of C (−IV), with CO2 and other carbonate forms existing in the most oxidized state (+IV). The major reservoirs of C are stored in the Earth’s crust, with much of it as inorganic carbonate and the remaining as organic C (e.g., kerogen) (figure 13.1; Sundquist, 1993). The global C cycle can be divided into short- and long-term cycles based on the vast differences in the turnover times of different C pools (Berner, 2004). The carbonate reservoir can be divided into two primary subreservoirs: (1) dissolved inorganic carbon (DIC) in the ocean (H2CO3, HCO3−, and CO32−), and (2) solid carbonate minerals [CaCO3, CaMg(CO3)2, and FeCO3] (Holmén, 2000). While the global C cycle is quite complex, it is perhaps the best understood of all the bioactive element cycles. In fact, there have been numerous review papers on this cycle (e.g., Keeling, 1973; Degens et al., 1984; Siegenthaler and Sarmiento, 1993; Sundquist, 1993; Schimel et al., 1995; Holmén, 2000). Much of the interest in the global C cycle in recent years stems from linkages with environmental issues concerning carbon-based greenhouse gases (e.g., CO2 and CH4) and their role in global climate change (Dickinson and Cicerone, 1986). As described in chapter 8, short-term controls on the C cycle are largely a function of the uptake of inorganic C by autotrophs to fuel fixation in photosynthesis, and the utilization of organic carbon as a food resource by heterotrophs recycling inorganic C back into the system. This short-term cycle, which allows for the transfer of C between the lithosphere, hydrosphere, biosphere, and atmosphere over periods of days to thousands of years, is relatively short in comparison to the more than 4 billion year age of the Earth.
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Schlesinger, William H., et Emily S. Bernhardt. « The Global Carbon Cycle ». Dans Biogeochemistry, 419–44. Elsevier, 2013. http://dx.doi.org/10.1016/b978-0-12-385874-0.00011-x.

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Schlesinger, William H. « The Global Carbon Cycle ». Dans Biogeochemistry, 308–21. Elsevier, 1991. http://dx.doi.org/10.1016/b978-0-12-625156-2.50016-7.

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Rapports d'organisations sur le sujet "Carbon cycle (Biogeochemistry)"

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Covey, C., K. Caldeira, T. Guilderson, P. Cameron-Smith, B. Govindasamy, C. Swanston, M. Wickett, A. Mirin et D. Bader. Global Biogeochemistry Models and Global Carbon Cycle Research at Lawrence Livermore National Laboratory. Office of Scientific and Technical Information (OSTI), mai 2005. http://dx.doi.org/10.2172/15016353.

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Twining, Benjamin S., Mak A. Saito, Alyson E. Santoro, Adrian Marchetti et Naomi M. Levine. US National BioGeoSCAPES Workshop Report. Woods Hole Oceangraphic Institution, janvier 2023. http://dx.doi.org/10.1575/1912/29604.

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BioGeoSCAPES (BGS) is an international program being developed to understand controls on ocean productivity and metabolism by integrating systems biology (‘omics) and biogeochemistry (Figure 1). To ensure global input into the design of the BGS Program, countries interested in participating were tasked with holding an organizing meeting to discuss the country-specific research priorities. A United States BGS planning meeting, sponsored by the Ocean Carbon & Biogeochemistry (OCB) Project Office, was convened virtually November 10-12, 2021. The objectives of the meeting were to communicate the planning underway by international partners, engage the US community to explore possible national contributions to such a program, and build understanding, support, and momentum for US efforts towards BGS. The meeting was well-attended, with 154 participants and many fruitful discussions that are summarized in this document. Key outcomes from the meeting were the identification of additional programs and partners for BGS, a prioritization of measurements requiring intercalibration, and the development of a consensus around key considerations to be addressed in a science plan. Looking forward, the hope is that this workshop will serve as the foundation for future US and international discussions and planning for a BGS program, enabled by NSF funding for an AccelNet project (AccelNet - Implementation: Development of an International Network for the Study of Ocean Metabolism and Nutrient Cycles on a Changing Planet (BioGeoSCAPES)), beginning in 2022.
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Stanley, Rachel H. R., Thomas Thomas, Yuan Gao, Cassandra Gaston, David Ho, David Kieber, Kate Mackey et al. US SOLAS Science Report. Woods Hole Oceanographic Institution, décembre 2021. http://dx.doi.org/10.1575/1912/27821.

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The Surface Ocean – Lower Atmosphere Study (SOLAS) (http://www.solas-int.org/) is an international research initiative focused on understanding the key biogeochemical-physical interactions and feedbacks between the ocean and atmosphere that are critical elements of climate and global biogeochemical cycles. Following the release of the SOLAS Decadal Science Plan (2015-2025) (Brévière et al., 2016), the Ocean-Atmosphere Interaction Committee (OAIC) was formed as a subcommittee of the Ocean Carbon and Biogeochemistry (OCB) Scientific Steering Committee to coordinate US SOLAS efforts and activities, facilitate interactions among atmospheric and ocean scientists, and strengthen US contributions to international SOLAS. In October 2019, with support from OCB, the OAIC convened an open community workshop, Ocean-Atmosphere Interactions: Scoping directions for new research with the goal of fostering new collaborations and identifying knowledge gaps and high-priority science questions to formulate a US SOLAS Science Plan. Based on presentations and discussions at the workshop, the OAIC and workshop participants have developed this US SOLAS Science Plan. The first part of the workshop and this Science Plan were purposefully designed around the five themes of the SOLAS Decadal Science Plan (2015-2025) (Brévière et al., 2016) to provide a common set of research priorities and ensure a more cohesive US contribution to international SOLAS.
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