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O papel das emissões de CO2 para a atmosfera, em rios da bacia do Ji-Paraná(RO), no ciclo regional do carbono; The role of CO2 outgassing from rivers of Ji-Paraná Basin(RO), in the regional carbon cycle

Rasera, Maria de Fatima Fernandes Lamy
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 04/08/2005 PT
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66.24%
O principal papel dos rios no ciclo global biogeoquímico do carbono tem sido considerado como o de exportador fluvial de carbono orgânico total (COT) e carbono inorgânico dissolvido (CID) para os oceanos. Entretanto, estudos recentes mostraram a importância dos fluxos evasivos de CO2 a partir de rios da Amazônia, sugerindo que uma parte significativa do carbono fixado pela floresta retornaria para a atmosfera por esta via. A troca gasosa entre a atmosfera e as águas supersaturadas dos rios é função do gradiente de concentração do gás através da interface ar-água. A pCO2 da água é fortemente determinada pela concentração de carbono inorgânico dissolvido e pH, que, por sua vez, são função de processos físicos, químicos e biológicos. O foco principal deste estudo foi estabelecer a importância dos fluxos evasivos de CO2 nos balanços de C, uma vez que os sistemas aquáticos são uma fonte significativa de C para a atmosfera nos ambientes tropicais úmidos. Ao mesmo tempo, avaliou-se a influência das concentrações de CID e pH na evasão de CO2. A área de estudo foi a bacia do rio Ji-Paraná, Rondônia. Vários rios desta bacia foram amostrados entre maio/99 e maio/03. Concentrações de CID, temperatura e pH foram utilizadas para calcular a pCO2 da água...

Principais aspectos do ciclo biogeoquímico do elemento carbono e seu contexto na atualidade; Main aspects of the global biogeochemical carbon cycle and context at the present time

Tonello, Victor Manoel Marques
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 04/05/2007 PT
Relevância na Pesquisa
56.11%
O presente trabalho consistiu na produção de uma síntese sobre os principais aspectos do ciclo biogeoquímico do carbono, envolvendo aspectos recentes do efeito estufa na atmosfera, sendo também contextualizadas as políticas públicas e seus mecanismos sócio-econômicos; inserida num contexto atual, das mudanças climáticas, intimamente relacionadas à Convenção-Quadro das Nações Unidas sobre Mudança do Clima, Protocolo de Kyoto e Mecanismos de Desenvolvimento Limpo. Os ecossistemas terrestres prestam enorme contribuição de serviços ambientais ao homem na forma de oferta de água, alimentos e insumos gerais. Estes ganhos são sustentáveis na medida em que haja um equilíbrio estável entre a entrada e saída de certas variáveis. Ainda não se entende satisfatoriamente a funcionalidade dos ecossistemas naturais e sua plena interação com o clima, nas escalas local, regional e global; portanto, é uma responsabilidade social antecipar o entendimento dessa relação, antes que tudo se transforme. Não se sabe ao certo todas as conseqüências do aumento excessivo na temperatura terrestre, mas são esperadas alterações profundas em diversos ecossistemas, por exemplo: descongelamento das calotas polares e o conseqüente alagamento de regiões costeiras...

Composição isotópica e fluxos de CO2 em área de Cerrado (Parque Estadual de Vassununga, SP); Isotopic composition and carbon dioxide fluxes in an area of Cerrado (State Park of Vassununga, SP)

Dias, Jádson Dezincourt
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 08/01/2010 PT
Relevância na Pesquisa
56.08%
O presente estudo foi desenvolvido em uma área de Cerrado stricto sensu, localizado no Parque Estadual de Vassununga, próximo ao município de Santa Rita do Passa Quatro, interior de São Paulo. O objetivo deste trabalho foi mensurar os fluxos de CO2, liberado pelos processos respiratórios da vegetação e do solo (heterotrófica + autotrófica) para aferir a importância relativa destes compartimentos na respiração total do ecossistema, utilizando-se da técnica isotópica. Foi utilizada a técnica da reta de keeling plot, para determinar os valores isotópicos respirados pelo ecossistema, e pelos componentes vegetais (serapilheira, madeira morta, raízes, folha e ramo). De acordo com os resultados, os valores isotópicos do CO2 respirado pelos componentes autotróficos e heterotróficos, foram significativamente influenciados pela sazonalidade, ficando mais enriquecidos em 13C durante o período seco. As correlações encontradas entre os valores do 'delta'13C- CO2 respirado pelos componentes e os fatores ambientais, como temperatura e umidade indicaram uma relação significativa. Os valores do 'delta'13C-CO2 respirado pelo ecossistema foram menos enriquecidos em 13C quando houve maior disponibilidade de água no sistema. O valor isotópico do 'delta'13C-CO2 respirado pelo ecossistema Cerrado foi de - 25...

Discursos escolares sobre o ciclo do carbono; Speeches on the school cycle of carbon

Cristiane Oliveira de Barros
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 29/08/2011 PT
Relevância na Pesquisa
56.21%
Entender o funcionamento de nosso planeta em sua complexibilidade, em diferentes processos e acoplamentos entre eles, tem sido um desafio para cientistas em todo mundo em diversas áreas. Estender este conhecimento, a perspectiva da sua complexidade, à escola e aos alunos é um desafio ainda maior, já que passa pela estrutura curricular, produção de materiais didáticos, avaliação e mediação docente. Isso certamente também se relaciona com questões ambientais. Discursos sobre ambiente são produzidos por diversas ciências, com seus arquivos e suas condições de produção, mas também por outras vozes e em outras instâncias e instituições. Discursos esses que significam e re-significam as relações homem/natureza, ciências humanas/ciência naturais, homem/ambiente, relações entre sociedade, ciência, tecnologia e ambiente. Dentre as questões atualmente mais discutidas em torno da temática ambiental estão aquelas relacionadas ao aquecimento global e às mudanças climáticas, envolvidas em controvérsias sobre a ação antrópica e, principalmente no que diz respeito ao aumento do CO2 atmosférico e sua possível relação com possíveis mudanças no clima da Terra. Alguns desses discursos que significam o ambiente de diferentes maneiras chegam à escola...

The Impact of Agricultural Soil Erosion on the Global Carbon Cycle

Van Oost, K.; Quine, T. A.; Govers, G.; De Gryze, S.; Six, J.; Harden, J. W.; Ritchie, J. C.; McCarty, G. W.; Heckrath, G.; Kosmas, C.; Giraldez, J. V.; Marques da Silva, José Rafael; Merckx, R.
Fonte: American Association for the Advancement of Science Publicador: American Association for the Advancement of Science
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.15%
Agricultural soil erosion is thought to perturb the global carbon cycle, but estimates of its effect range from a source of 1 petagram per year−1 to a sink of the same magnitude. By using caesium-137 and carbon inventory measurements from a large-scale survey, we found consistent evidence for an erosion-induced sink of atmospheric carbon equivalent to approximately 26% of the carbon transported by erosion. Based on this relationship, we estimated a global carbon sink of 0.12 (range 0.06 to 0.27) petagrams of carbon per year−1 resulting from erosion in the world’s agricultural landscapes. Our analysis directly challenges the view that agricultural erosion represents an important source or sink for atmospheric CO2.

Precipitation Mediates the Response of Carbon Cycle to Rising Temperature in the Mid-to-High Latitudes of the Northern Hemisphere

Lin, Xin; Li, Junsheng; Luo, Jianwu; Wu, Xiaopu; Tian, Yu; Wang, Wei
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 14/07/2015 EN
Relevância na Pesquisa
46.24%
Over the past decades, rising air temperature has been accompanied by changes in precipitation. Despite relatively robust literature on the temperature sensitivity of carbon cycle at continental to global scales, less is known about the way this sensitivity is affected by precipitation. In this study we investigate how precipitation mediates the response of the carbon cycle to warming over the mid-to-high latitudes in the Northern Hemisphere (north of 30°N). Based on atmospheric CO2 observations at Point Barrow (BRW) in Alaska, satellite-derived NDVI (a proxy of vegetation productivity), and temperature and precipitation data, we analyzed the responses of carbon cycle to temperature change in wet and dry years (with precipitation above or below the multiyear average). The results suggest that, over the past three decades, the net seasonal atmospheric CO2 changes at BRW were significantly correlated with temperature in spring and autumn, yet only weakly correlated with temperature and precipitation during the growing season. We further found that responses of the net CO2 changes to warming in spring and autumn vary with precipitation levels, with the absolute temperature sensitivity in wet years roughly twice that in dry years. The analyses of NDVI and climate data also identify higher sensitivity of vegetation growth to warming in wet years for the growing season...

Isotopic Constraints on the Late Archean Carbon Cycle from the Transvaal Supergroup along the Western Margin of the Kaapvaal Craton, South Africa

Knoll, Andrew; Horstmann, Uwe E.; Strauss, Harald; Goldberg, Tatiana; Beukes, Nicolas J.; Lacassie, Juan P.; Schroeder, Stefan; Fischer, Woodward W.; Schrag, Daniel P.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
46.25%
Few existing studies illuminate the operation of the carbon cycle before the rise of atmospheric oxygen circa 2400 million years ago. Stable carbon isotopic measurements of shallow stromatolitic carbonates (~0 [parts per thousand] VPDB) and basinal carbonate minerals (-6 [parts per thousand]) in iron formation have been used to infer a strong isotopic depth gradient in Archean ocean basins. From new diamond drill cores obtained by the Agouron Drilling Project from the Griqualand West structural basin in the Northern Cape Province, South Africa, we present [delta C-13] data from carbonates and organic matter that offer fresh insights into the Late Archean carbon cycle. Three drill cores cover the development, progradation, and ultimate demise (by drowning) of the Campbellrand carbonate platform (ca. 2590-2500 Ma); one captures the platform top shallow marine and intertidal paleoenvironments, the other two run through slope and basinal sections deposited adjacent to the platform margin, increasing in water depth (likely to >1 km). Both shallow and deep-water carbonates precipitated on the seafloor consistently show [delta C-13] values around -0.5 [parts per thousand], incompatible with a strong Late Archean isotopic depth gradient. A mathematical model suggests that these isotopic data are consistent with a reduced biological pump...

Rate My Data: Quantifying the Value of Ecological Data for Models of Terrestrial Carbon Cycle

Keenan, Trevor; Davidson, Eric; Munger, James; Richardson, Andrew
Fonte: Ecological Society of America Publicador: Ecological Society of America
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
56.18%
Primarily driven by concern about rising levels of atmospheric CO2, ecologists and earth system scientists are collecting vast amounts of data related to the carbon cycle. These measurements are generally time-consuming and expensive to make, and, unfortunately, we live in an era where research funding is increasingly hard to come by. Thus, important questions are: ‘Which data streams provide the most valuable information? ’ and, ‘How much data do we need? ’ These questions are relevant not only for model developers, who need observational data to improve, constrain and test their models, but also for experimentalists and those designing ecological observation networks. Here we address these questions using a model-data fusion approach. We constrain a process-oriented, forest ecosystem C cycle model with seventeen different data streams from the Harvard Forest. We iteratively rank each data source according to its contribution to reducing model uncertainty. Results show the importance of some measurements commonly unavailable to carbon cycle modelers, such as estimates of turnover times from different carbon pools. Surprisingly, many data sources are relatively redundant in the presence of others, and do not lead to a significant improvement in model performance. A few select data sources lead to the largest reduction in parameter based model uncertainty. Projections of future carbon cycling were poorly constrained when only hourly net ecosystem exchange measurements were used to inform the model. They were well constrained...

Consequences of Considering Carbon/Nitrogen Interactions on the Feedbacks between Climate and the Terrestrial Carbon Cycle

Sokolov, Andrei P.; Kicklighter, David W.; Melillo, Jerry M.; Felzer, Benjamin; Schlosser, C. Adam; Cronin, Timothy W.
Fonte: MIT Joint Program on the Science and Policy of Global Change Publicador: MIT Joint Program on the Science and Policy of Global Change
Tipo: Relatório
EN_US
Relevância na Pesquisa
46.25%
A number of observational studies indicate that carbon sequestration by terrestrial ecosystems in a world with an atmosphere richer in carbon dioxide and a warmer climate depends on the interactions between the carbon and nitrogen cycles. However, most terrestrial ecosystem models being used in climate-change assessments do not take into account these interactions. Here we explore how carbon/nitrogen interactions in terrestrial ecosystems affect feedbacks to the climate system using the MIT Integrated Global Systems Model (IGSM) and its terrestrial ecosystems submodel, the Terrestrial Ecosystems Model (TEM). We use two versions of TEM, one with (standard TEM) and one without (carbon-only TEM) carbon/nitrogen interactions. Feedbacks between climate and the terrestrial carbon cycle are estimated by comparing model response to an increase in atmospheric CO2 concentration with and without climate change. Overall, for small or moderate increases in surface temperatures, the terrestrial biosphere simulated by the standard TEM takes up less atmospheric carbon than the carbon-only version, resulting in a larger increase in atmospheric CO2 concentration for a given amount of carbon emitted. With strong surface warming, the terrestrial biosphere simulated by the standard TEM may still become a carbon source early in the 23rd century. Our simulations also show that consideration of carbon/nitrogen interactions not only limits the effect of CO2 fertilization in the absence of climate change...

The Paleocene-Eocene thermal maximum: a perturbation of carbon cycle, climate, and biosphere with implications for the future

McInerney, F.; Wing, S.
Fonte: Annual Reviews Publicador: Annual Reviews
Tipo: Artigo de Revista Científica
Publicado em //2011 EN
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66.17%
During the Paleocene-Eocene Thermal Maximum (PETM), ~56 Mya, thousands of petagrams of carbon were released into the ocean-atmosphere system with attendant changes in the carbon cycle, climate, ocean chemistry, and marine and continental ecosystems. The period of carbon release is thought to have lasted <20 ka, the duration of the whole event was ~200 ka, and the global temperature increase was 5–8°C. Terrestrial and marine organisms experienced large shifts in geographic ranges, rapid evolution, and changes in trophic ecology, but few groups suffered major extinctions with the exception of benthic foraminifera. The PETM provides valuable insights into the carbon cycle, climate system, and biotic responses to environmental change that are relevant to long-term future global changes.; Francesca A. McInerney and Scott L. Wing

Emulating coupled atmosphere-ocean and carbon cycle models with a simpler model, MAGICC6 - Part 1: Model description and calibration

Meinshausen, M.; Raper, S.; Wigley, T.
Fonte: European Geophysical Society Publicador: European Geophysical Society
Tipo: Artigo de Revista Científica
Publicado em //2011 EN
Relevância na Pesquisa
46.24%
Current scientific knowledge on the future response of the climate system to human-induced perturbations is comprehensively captured by various model intercomparison efforts. In the preparation of the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC), intercomparisons were organized for atmosphere-ocean general circulation models (AOGCMs) and carbon cycle models, named “CMIP3” and “C⁴MIP”, respectively. Despite their tremendous value for the scientific community and policy makers alike, there are some difficulties in interpreting the results. For example, radiative forcings were not standardized across the various AOGCM integrations and carbon cycle runs, and, in some models, key forcings were omitted. Furthermore, the AOGCM analysis of plausible emissions pathways was restricted to only three SRES scenarios. This study attempts to address these issues. We present an updated version of MAGICC, the simple carbon cycle-climate model used in past IPCC Assessment Reports with enhanced representation of time-varying climate sensitivities, carbon cycle feedbacks, aerosol forcings and ocean heat uptake characteristics. This new version, MAGICC6, is successfully calibrated against the higher complexity AOGCMs and carbon cycle models. Parameterizations of MAGICC6 are provided. The mean of the emulations presented here using MAGICC6 deviates from the mean AOGCM responses by only 2.2% on average for the SRES scenarios. This enhanced emulation skill in comparison to previous calibrations is primarily due to: making a “like-with-like comparison” using AOGCM-specific subsets of forcings; employing a new calibration procedure; as well as the fact that the updated simple climate model can now successfully emulate some of the climate-state dependent effective climate sensitivities of AOGCMs. The diagnosed effective climate sensitivity at the time of CO₂ doubling for the AOGCMs is on average 2.88°C...

Assessment of the Risk of Amazon Dieback

Vergara, Walter; Scholz, Sebastian M.
Fonte: World Bank Publicador: World Bank
Tipo: Publications & Research :: Publication; Publications & Research :: Publication
ENGLISH
Relevância na Pesquisa
46.25%
The Amazon basin is a key component of the global carbon cycle. The old-growth rainforests in the basin represent storage of ~ 120 petagrams of carbon (Pg C) in their biomass. Annually, these tropical forests process approximately 18 Pg C through respiration and photosynthesis. This is more than twice the rate of global anthropogenic fossil fuel emissions. The basin is also the largest global repository of biodiversity and produces about 20 percent of the world's flow of fresh water into the oceans. Despite the large carbon dioxide (CO2) efflux from recent deforestation, the Amazon rainforest ecosystem is still considered to be a net carbon sinks of 0.8-1.1 Pg C per year because growth on average exceeds mortality (Phillips et al. 2008). However, current climate trends and human-induced deforestation may be transforming forest structure and behavior (Phillips et al. 2009). Increasing temperatures may accelerate respiration rates and thus carbon emissions from soils (Malhi and Grace 2000). High probabilities for modification in rainfall patterns (Malhi et al. 2008) and prolonged drought stress may lead to reductions in biomass density. Resulting changes in evapo-transpiration and therefore convective precipitation could further accelerate drought conditions and destabilize the tropical ecosystem as a whole...

Uncertainty in atmospheric CO₂ predictions from a parametric uncertainty analysis of a global carbon cycle model; Uncertainty in atmospheric carbon dioxide predictions from a parametric uncertainty analysis of a global carbon cycle model

Fonte: MIT Joint Program on the Science and Policy of Global Change Publicador: MIT Joint Program on the Science and Policy of Global Change
Formato: 25 p.; 472964 bytes; application/pdf
ENG
Relevância na Pesquisa
46.26%
Key uncertainties in the global carbon cycle are explored with a 2-D model for the oceanic carbon sink. By calibrating the key parameters of this ocean carbon sink model to widely referenced values, it produces an average oceanic carbon sink during the 1980s of 1.94 Pg/yr, consistent with the range estimated by the IPCC of 2.0 Pg/yr +/- 0.8 Pg/yr. A sensitivity analysis of the parameter values used as inputs to the 2-D ocean carbon sink model developed for this study suggests that the IPCC's range for the oceanic carbon sink of 1.2 to 2.8 Pg/yr during the 1980s may be too conservative. By applying the Probabilistic Collocation Method to this simple ocean carbon sink model, the uncertainty in the size of the oceanic sink for carbon and hence future atmospheric CO₂ concentrations is quantitatively examined. An average 1980s oceanic carbon sink of 2.06 ± 0.9 Pg/y (with 67% confidence) is estimated. This uncertainty is found to be dominated the uncertainty in by the rate of vertical mixing of dissolved carbon from the surface into the deep ocean which is parameterized in this study by vertical diffusion. It is observed that a wide range of parameter values can be used to balance the contemporary carbon cycle due to the large uncertainties in the total oceanic and terrestrial sinks. For a reference set of emissions similar to the IS92a scenario of the IPCC...

The Role of Hyperspectral data in understanding the Global Carbon Cycle

Ustin, S. L.; Zarco-Tejada, Pablo J.; Asner, G.
Fonte: Conselho Superior de Investigações Científicas Publicador: Conselho Superior de Investigações Científicas
Tipo: Comunicación de congreso Formato: 957844 bytes; application/pdf
ENG
Relevância na Pesquisa
66.13%
Presented at the 2001 AVIRIS Workshop, JPL-NASA, Pasadena, California, Feb. 27th - March 2nd, 2001; A major challenge in predicting the consequences of global climate change is to accurately estimate carbon stocks and to predict future CO2 sequestration and dynamics (NRC, 1999). Climate dynamics and human activities drive changes in land cover and land use, creating unpredictable patterns of disturbance and environmental stresses in natural and managed ecosystems. These changes affect carbon storage, the distribution of carbon in above and below ground compartments, ecosystem productivity, and biogeochemical cycles. A wide range of information is needed to monitor the carbon cycle from properties that regulate fluxes of CO2, to estimates of standing biomass, land cover types, and land use history. Satellite observations provide the only practical means to obtain a synoptic view of the Earth's ecosystems, their spatial distribution, extent, and temporal dynamics.; Peer reviewed

A data assimilation framework for constraining upscaled cropland carbon flux seasonality and biometry with MODIS

Sus, Oliver; Heuer, M. W.; Meyers, T. P.; Williams, M.
Fonte: Universidade Autônoma de Barcelona Publicador: Universidade Autônoma de Barcelona
Tipo: Artigo de Revista Científica Formato: application/pdf
Publicado em //2013 ENG
Relevância na Pesquisa
56.12%
Agroecosystem models are strongly dependent on information on land management patterns for regional applications. Land management practices play a major role in determining global yield variability, and add an anthropogenic signal to the observed seasonality of atmospheric CO₂ concentrations. However, there is still little knowledge on spatial and temporal variability of important farmland activities such as crop sowing dates, and thus these remain rather crudely approximated within carbon cycle studies. In this study, we present a framework allowing for spatio-temporally resolved simulation of cropland carbon fluxes under observational constraints on land management and canopy greenness. We apply data assimilation methodology in order to explicitly account for information on sowing dates and model leaf area index. MODIS 250 m vegetation index data were assimilated both in batch-calibration for sowing date estimation and sequentially for improved model state estimation, using the ensemble Kalman filter (EnKF), into a crop carbon mass balance model (SPAc). In doing so, we are able to quantify the multiannual (2000–2006) regional carbon flux and biometry seasonality of maize–soybean crop rotations surrounding the Bondville Ameriflux eddy covariance site...

Isotopic constraints on the Late Archean carbon cycle from the Transvaal Supergroup along the western margin of the Kaapvaal Craton, South Africa

Fischer, W. W.; Schroeder, S.; Lacassie, J. P.; Beukes, N. J.; Goldberg, T.; Strauss, H.; Horstmann, U. E.; Schrag, D. P.; Knoll, A. H.
Fonte: Elsevier Publicador: Elsevier
Tipo: Article; PeerReviewed Formato: application/pdf
Publicado em /03/2009
Relevância na Pesquisa
46.25%
Few existing studies illuminate the operation of the carbon cycle before the rise of atmospheric oxygen circa 2400 million years ago. Stable carbon isotopic measurements of shallow stromatolitic carbonates (~0‰ VPDB) and basinal carbonate minerals (−6‰) in iron formation have been used to infer a strong isotopic depth gradient in Archean ocean basins. From new diamond drill cores obtained by the Agouron Drilling Project from the Griqualand West structural basin in the Northern Cape Province, South Africa, we present δ^(13)C data from carbonates and organic matter that offer fresh insights into the Late Archean carbon cycle. Three drill cores cover the development, progradation, and ultimate demise (by drowning) of the Campbellrand carbonate platform (ca. 2590–2500 Ma); one captures the platform top shallow marine and intertidal paleoenvironments, the other two run through slope and basinal sections deposited adjacent to the platform margin, increasing inwater depth (likely to >1 km). Both shallowand deep-water carbonates precipitated on the seafloor consistently show δ^(13)C values around −0.5‰, incompatible with a strong Late Archean isotopic depth gradient. A mathematical model suggests that these isotopic data are consistent with a reduced biological pump...

Technopolitical Regimes and Climate Change: A Transcript of an Interview with the Carbon Cycle

Barnes, Philip
Fonte: New Vision for Public Affairs Publicador: New Vision for Public Affairs
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
66.21%
Despite the urgent response that climate change demands, debate over climate change policy goes round and round without showing signs that it can rest long enough for action to be taken. Meanwhile, the situation with the atmospheric commons continues to deteriorate. In a desperate attempt to constructively contribute to the climate change debate and break through the morass, this paper engages with Act or Network Theory which affords practitioners the freedom to dialogue with the non-human. The result is a transcription of an interview with The Carbon Cycle. Using the concept of the technopolitical regime, The Carbon Cycle identifies two broadly defined philosophies that humans use to frame climate change policy. The two technopolitical regimes, what The Carbon Cycle calls the Interventionists and the Egalitarians, are informed by conflicting values. According to The Carbon Cycle, humans will need to face the difficult challenge of negotiating a policy response to climate change that lies somewhere between the interventionist and the egalitarian strategies. Depending on the policy approach taken, the implications for society-nature relationships and democratic governance are radically different and are teased out in this conversation.

Coral Reef Sedimentation on Rodrigues and the Western Indian Ocean and its Impact on the Carbon Cycle

Rees, Siwan A.; Opdyke, Bradley; Wilson, Paul A.; Fifield, L Keith
Fonte: Royal Society of London Publicador: Royal Society of London
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
56.04%
Coral reefs in the southwest Indian Ocean cover an area of ca. 18 530 km2 compared with a global reef area of nearly 300 000 km 2. These regions are important as fishing grounds, tourist attractions and as a significant component of the global carbon cycle. The mass of calcium carbonate stored within Holocenc neritic sediments is a number that we are only now beginning to quantify with any confidence, in stark contrast to the mass and sedimentation rates associated with pelagic calcium carbonate, which have been relatively well defined for decades. We report new data that demonstrate that the reefs at Rodrigues, like those at Réunion and Mauritius, only reached a mature state (reached sea level) by 2-3 ka: thousands of years later than most of the reefs in the Australasian region. Yet field observations show that the large lagoon at Rodrigues is already completely full of carbonate detritus (typical lagoon depth less than 1 m at low spring tide). The presence of aeolian dunes at Rodrigues indicates periodic exposure of past lagoons throughout the Pleistocene. The absence of elevated Pleistocene reef deposits on the island indicates that the island has not been uplifted. Most Holocene reefs are between 15 and 20 m in thickness and those in the southwest Indian Ocean appear to be consistent with this observation. We support the view that the CO2 flux associated with coral-reef growth acts as a climate change amplifier during deglaciation...

COINS: an integrative modelling shell for carbon accounting and general ecological analysis

Roxburgh, Stephen; Davies, Ian
Fonte: Pergamon-Elsevier Ltd Publicador: Pergamon-Elsevier Ltd
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
56.06%
It is common for a range of models to be developed to investigate broadly similar ecological and environmental phenomena. This inevitably results in collections of models that, although individually possessing unique characteristics, also share a number of key similarities. Here we describe a new modelling shell called COINS (COmparison and INtegration Shell) within which many related models can be co-located, and where model similarities are exploited to facilitate rapid model development and analysis. The philosophy underlying COINS is to separate computer code that is shared across different models, such as common process descriptions, or shared data input and output routines, from the core equations of each model. This reduces code redundancy, allowing the modeller to more directly focus on the process of model formulation. As an integrative tool, COINS can be used to (i) construct component models, (ii) integrate existing components to develop a simulation, and (iii) allow end users to run a simulation for analysis and scenario comparison. The COINS software has been developed with a specific focus on modelling the terrestrial carbon cycle, but its utility is potentially broader, particularly within the general area of ecological analysis and natural resource management. Three examples based on terrestrial carbon accounting at a range of spatial scales (point...

Carbon Cycle: Biogeochemical, Physical Processes and Compartment Interactions in the Todos os Santos Bay; Ciclo do Carbono: Processos Biogeoquímicos, Físicos e Interações entre Compartimentos na Baía de Todos os Santos

Marcelo F. L. de Souza; Universidade Estadual de Santa cruz; Cybelle M. Longhini; Floram Engenharia e Meio Ambiente; Ananda M. Silva; Bahia Mineração S. A.; Carlos Alessandre D. Lentini; Universidade Federal da Bahia
Fonte: Revista Virtual de Química Publicador: Revista Virtual de Química
Tipo: ; Formato: binary/octet-stream
Publicado em 18/10/2012 PT
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56.13%
Processes involving carbon in coastal marine ecosystems are important to the global cycle of this element. These processes have been changed by human activities, resulting in effects at local, regional and global scale. Studies concerning carbon cycling in this interface between land and ocean are still scarce, especially in tropical regions. The present article provides a brief review of these processes, characterizing biological, chemical and physical aspects related to the carbon cycle in the Todos os Santos Bay. A preliminary estimate of net community metabolism (gross primary production – respiration) was made using data available in the literature for each kind of environment, revealing the importance of pelagic and soft bottom sediments to the production of organic matter. The relevance of mangrove and reef communities to the carbon fluxes is also described. DOI: 10.5935/1984-6835.20120044; Os processos envolvendo o carbono em ecossistemas marinhos costeiros são importantes para o ciclo global deste elemento. Estes processos têm sido modificados pelas atividades humanas, com implicações em escala local, regional e global. Esta região de transição entre continentes e oceanos ainda é pouco estudada com relação à ciclagem do carbono...