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| Registros recuperados: 36 | |
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| Watson, Andrew J.; Metzl, Nicolas; Schuster, Ute. |
| The oceans are an important sink for anthropogenically produced CO2, and on time scales longer than a century they will be the main repository for the CO2 that humans are emitting. Our knowledge of how ocean uptake varies (regionally and temporally) and the processes that control it is currently observation-limited. Traditionally, and based on sparse observations and models at coarse resolution, ocean uptake has been thought to be relatively invariant. However, in the few places where we have enough observations to define the uptake over periods of many years or decades, it has been found to change substantially at basin scales, responding to indices of climate variability. We illustrate this for three well-studied regions: the equatorial Pacific, the... |
| Tipo: Text |
Palavras-chave: CO2; Carbon cycle; Greenhouse gases; Atmospheric oxygen. |
| Ano: 2011 |
URL: https://archimer.ifremer.fr/doc/00144/25561/23702.pdf |
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| Mckinley, Galen A.; Fay, Amanda R.; Eddebbar, Yassir A.; Gloege, Lucas; Lovenduski, Nicole S.. |
| The ocean has absorbed the equivalent of 39% of industrial‐age fossil carbon emissions, significantly modulating the growth rate of atmospheric CO2 and its associated impacts on climate. Despite the importance of the ocean carbon sink to climate, our understanding of the causes of its interannual‐to‐decadal variability remains limited. This hinders our ability to attribute its past behavior and project its future. A key period of interest is the 1990s, when the ocean carbon sink did not grow as expected. Previous explanations of this behavior have focused on variability internal to the ocean or associated with coupled atmosphere/ocean modes. Here, we use an idealized upper ocean box model to illustrate that two external forcings are sufficient to explain... |
| Tipo: Text |
Palavras-chave: Carbon cycle; Ocean carbon sink; Forced; Internal. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00676/78775/80950.pdf |
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| Thevenon, Florian; Williamson, David; Bard, Edouard; Anselmetti, Flavio S.; Beaufort, Luc; Cachier, Helene. |
| This paper addresses the quantification of combustion-derived products in oceanic and continental sediments by optical and chemical approaches, and the interest of combining such methods for reconstructing past biomass burning activity and the pyrogenic carbon cycle. In such context, the dark particles >0.2 mu m(2) remaining after the partial digestion of organic matter are optically counted by automated image analysis and defined as charcoal, while the elemental carbon remaining after thermal and chemical oxidative treatments is quantified as black carbon (BC). The obtained pyrogenic carbon records from three sediment core-based case studies, (i) the Late Pleistocene equatorial Pacific Ocean. (ii) the mid-Holocene European Lake Lucerne, and (iii) the... |
| Tipo: Text |
Palavras-chave: Biomass burning; Carbon cycle; Charcoal; Black carbon; Climate; Human impact. |
| Ano: 2010 |
URL: https://archimer.ifremer.fr/doc/00231/34198/32764.pdf |
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| Bertoni, R. |
| The radiochemical methods proposed for evaluating heterotrophic activity in waters have been severely criticized in recent years because they are not considered to be sufficiently realistic. Thus, the possibility of directly measuring the heterotrophic consumption of naturally occurring Organic Carbon (OC) in fresh water samples incubated under controlled conditions has been evaluated. The analytical performances of two OC analyzers utilizable for this purpose are discussed here, and some examples of the results obtained by the direct measurement of OC consumption are presented. The consumption rates thus measured ranged from 11.6 to 50.2 mu gC/ 1.h. Although the technique discussed here is less sensitive than radiochemical methods, the few assumptions... |
| Tipo: Text |
Palavras-chave: Biogeochemistry; Microbiology; Carbon cycle; Organic carbon; Water; Heterotrophic organisms; Analytical techniques. |
| Ano: 1984 |
URL: http://archimer.ifremer.fr/doc/1984/acte-950.pdf |
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| Dufresne, J-l.; Foujols, M-a.; Denvil, S.; Caubel, A.; Marti, O.; Aumont, Olivier; Balkanski, Y.; Bekki, S.; Bellenger, H.; Benshila, R.; Bony, S.; Bopp, L.; Braconnot, P.; Brockmann, P.; Cadule, P.; Cheruy, F.; Codron, F.; Cozic, A; Cugnet, D.; De Noblet, N.; Duvel, J-p.; Ethe,; Fairhead, L.; Fichefet, T.; Flavoni, S.; Friedlingstein, P.; Grandpeix, J-y.; Guez, L.; Guilyardi, E.; Hauglustaine, D.; Hourdin, F.; Idelkadi, A.; Ghattas, J.; Joussaume, S.; Kageyama, M.; Krinner, G.; Labetoulle, S.; Lahellec, A.; Lefebvre, M; Lefevre, F.; Levy, C.; Li, Zhanbin; Lloyd, J.; Lott, F.; Madec, G.; Mancip, M.; Marchand, M; Masson, S.; Meurdesoif, Y.; Mignot, J.; Musat, I.; Parouty, S.; Polcher, J.; Rio, C; Schulz, M.; Swingedouw, D.; Szopa, S.; Talandier, Claude; Terray, P.; Viovy, N.; Vuichard, N.. |
| We present the global general circulation model IPSL-CM5 developed to study the long-term response of the climate system to natural and anthropogenic forcings as part of the 5th Phase of the Coupled Model Intercomparison Project (CMIP5). This model includes an interactive carbon cycle, a representation of tropospheric and stratospheric chemistry, and a comprehensive representation of aerosols. As it represents the principal dynamical, physical, and bio-geochemical processes relevant to the climate system, it may be referred to as an Earth System Model. However, the IPSL-CM5 model may be used in a multitude of configurations associated with different boundary conditions and with a range of complexities in terms of processes and interactions. This paper... |
| Tipo: Text |
Palavras-chave: Climate; Climate change; Climate projections; Earth System Model; CMIP5; CMIP3; Greenhouse gases; Aerosols; Carbon cycle; Allowable emissions; RCP scenarios; Land use changes. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00138/24966/23079.pdf |
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| Faust, Johan C.; Tessin, Allyson; Fisher, Ben J.; Zindorf, Mark Sebastian; Papadaki, Sonia; Hendry, Katharine R.; Doyle, Katherine A.; März, Christian. |
| Burial of organic material in marine sediments represents a dominant natural mechanism of long-term carbon sequestration globally, but critical aspects of this carbon sink remain unresolved. Investigation of surface sediments led to the proposition that on average 10-20% of sedimentary organic carbon is stabilised and physically protected against microbial degradation through binding to reactive metal (e.g. iron and manganese) oxides. Here we examine the long-term efficiency of this rusty carbon sink by analysing the chemical composition of sediments and pore waters from four locations in the Barents Sea. Our findings show that the carbon-iron coupling persists below the uppermost, oxygenated sediment layer over thousands of years. We further propose that... |
| Tipo: Text |
Palavras-chave: Carbon cycle; Geochemistry. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00675/78755/80923.pdf |
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| Fassbender, Andrea J.; Sabine, Christopher L.; Palevsky, Hilary I.. |
| Surface ocean carbon chemistry is changing rapidly. Partial pressures of carbon dioxide gas (pCO(2)) are rising, pH levels are declining, and the ocean's buffer capacity is eroding. Regional differences in short-term pH trends primarily have been attributed to physical and biological processes; however, heterogeneous seawater carbonate chemistry may also be playing an important role. Here we use Surface Ocean CO2 Atlas Version 4 data to develop 12month gridded climatologies of carbonate system variables and explore the coherent spatial patterns of ocean acidification and attenuation in the ocean carbon sink caused by rising atmospheric pCO(2). High-latitude regions exhibit the highest pH and buffer capacity sensitivities to pCO(2) increases, while the... |
| Tipo: Text |
Palavras-chave: Ocean acidification; Carbon sink; Revelle factor; Carbon cycle. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00661/77321/78794.pdf |
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| Lefèvre, Nathalie; Mejia, Carlos; Khvorostyanov, Dmitry; Beaumont, Laurence; Koffi, Urbain. |
| The carbon system in the eastern tropical Atlantic remains poorly known. The variability and drivers of the carbon system are assessed using surface dissolved inorganic carbon (DIC), alkalinity (TA) and fugacity of CO2 (fCO2) measured in the 12° N–12° S, 12° W–12° E region from 2005 to 2019. A relationship linking DIC to temperature, salinity and year has been determined, with salinity being the strongest predictor. The seasonal variations of DIC, ranging from 80 to 120 mol kg−1, are more important than the year-to-year variability that is less than 50 mol kg−1 over the 2010–2019 period. DIC and TA concentrations are lower in the northern part of the basin where surface waters are fresher and warmer. Carbon supply dominates over biological carbon uptake... |
| Tipo: Text |
Palavras-chave: Carbon cycle; Tropical Atlantic; Dissolved inorganic carbon; Alkalinity. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00678/79046/81494.pdf |
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| Durrieu De Madron, X; Denis, L; Diaz, F; Garcia, N; Guieu, C; Grenz, C; Loye-pilot, Md; Ludwig, W; Moutin, T; Raimbault, P; Ridame, C. |
| Shelf-slope exchanges and budgets of organic and inorganic nutrients are calculated for the Gulf of Lion continental margin in the northwestern Mediterranean. Computations are based on data from three seasonal marine surveys performed in March 1998, June 1998 and January 1999 in the framework of the French Programme National d'Environnement Cotier. A Land-Ocean Interactions in the Coastal Zone type box model is used to calculate the advective exchanges between the shelf and the adjacent open sea and to estimate the budgets of non-conservative elements (DIP, DIN, DOP, DON, DOC, POC, PON, POP). These budgets consider river discharges, urban sewage supply, atmospheric deposition, and fluxes at the water-sediment and shelf-slope interfaces. Uncertainties on... |
| Tipo: Text |
Palavras-chave: Mer Méditerranée; Echanges côte-large; Fonctionnement de l’écosystème; Cycle du carbone; Bilan de sels nutritifs; Mediterranean Sea; Shelf-slope exchanges; Ecosystem functioning; Carbon cycle; Nutrients budget. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/00301/41236/40426.pdf |
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| Jennerjahn, Tc; Ittekkot, V. |
| The nature of sedimentary organic matter from mangroves and the continental margin of eastern Brazil (8 degrees-24 degrees S) has been investigated in order to obtain information on sources and diagenetic processes. The organic matter content of mangrove sediments is three to four times higher than the maximum content of continental margin sediments. Downslope distribution of organic carbon, nitrogen, amino acids and hexosamines shows an enrichment in water depths between 800 m and 1000 m. The distribution of individual amino acids and hexosamines is highly variable in sedimentary organic matter from mangroves and the continental margin, and the observed compositional differences are mainly due to diagenetic alteration. Organic matter is highly reactive in... |
| Tipo: Text |
Palavras-chave: Organic carbon; Amino acids; Carbon cycle; Mangroves; Continental margin. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00093/20403/18070.pdf |
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| Ronge, Thomas A.; Prange, M.; Mollenhauer, Gesine; Ellinghausen, Maret; Kuhn, G.; Tiedemann, R.. |
| It is widely assumed that the ventilation of the Southern Ocean played a crucial role in driving glacial‐interglacial atmospheric CO2‐levels. So far however, ventilation records from the Indian sector of the Southern Ocean, are widely missing. Here we present reconstructions of water residence times (depicted as ΔΔ14C and Δδ13C) for the last 32,000 years on sediment records from the Kerguelen Plateau and the Conrad Rise (~570‐2500 m water depth), along with simulated changes in ocean stratification from a transient climate model experiment. Our data indicate that Circumpolar Deep Waters in the Indian Ocean were part of the glacial carbon pool. At our sites, close to or bathed by upwelling deep‐waters, we find two pulses of decreasing ΔΔ14C and δ13C values... |
| Tipo: Text |
Palavras-chave: Radiocarbon; Ventilation; Southern Ocean; Younger Dryas; Carbon cycle; Indian Ocean. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00611/72351/71258.pdf |
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| Touratier, Franck; Goyet, C; Coatanoan, Christine; Andrie, C. |
| With a limited number of properties (salinity, temperature, total dissolved inorganic carbon, total alkalinity, and oxygen) from a recent cruise in the tropical Atlantic Ocean, We use the simple and recent approach TrOCA (Tracer combining Oxygen, inorganic Carbon, and total Alkalinity) to estimate the distribution of anthropogenic CO2 along three latitudinal sections. In order to assess the quality of the anthropogenic CO2 distribution, results from the method are compared to the CFC-11 measurements. We discuss the large-scale distribution of the main water masses of the tropical Atlantic Ocean in the light of the anthropogenic CO2 and the CFC-11 distributions. Keeping in mind that the anthropogenic CO2 emission began similar to 60 years earlier than that... |
| Tipo: Text |
Palavras-chave: Tropical belt; Atlantic Ocean; Water mass; Carbon cycle. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-886.pdf |
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| Couldrey, Matthew P.; Oliver, Kevin I. C.; Yool, Andrew; Halloran, Paul R.; Achterberg, Eric P.. |
| The North Atlantic is an important basin for the global ocean's uptake of anthropogenic and natural carbon dioxide (CO2), but the mechanisms controlling this carbon flux are not fully understood. The air-sea flux of CO2, F, is the product of a gas transfer velocity, k, the air-sea CO2 concentration gradient, Delta pCO(2), and the temperature-and salinity-dependent solubility coefficient, alpha, k is difficult to constrain, representing the dominant uncertainty in F on short (instantaneous to interannual) timescales. Previous work shows that in the North Atlantic, Delta pCO(2) and k both contribute significantly to interannual F variability but that k is unimportant for multidecadal variability. On some timescale between interannual and multidecadal, gas... |
| Tipo: Text |
Palavras-chave: Carbon flux; Gas transfer velocity; Carbon cycle; Ocean model; Climate dynamics; Variability. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00383/49418/49868.pdf |
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| Morita, R; Jones, R. |
| The nitrifying bacteria were found to survive 24 weeks in the absence of ammonium without decreasing their number of cell size. Because H sub(2), CO, and CH sub(4) are present in the marine environment, these substrates were investigated as a possible source of the energy of maintenance for the nitrifying bacteria. super(14)CO and super(14)CH sub(4) were found to be oxidized by the nitrifiers. N-serve was found to inhibit the oxidation of CO. Using the nitrifiers' ability to oxide CO, a method for the determination of the nitrification rate was developed. The ability of nitrifiers to oxidize CO may play a significant role in the cycling of CO sub(2) in the marine environment. Whether CO and CH sub(4) oxidation play a role in the survival of nitrifiers in... |
| Tipo: Text |
Palavras-chave: Methane; Carbon dioxide; Survival; Bacteria; Nitrification; Nitrogen cycle; Oxidation; Carbon cycle; Biogeochemistry; Metabolism. |
| Ano: 1984 |
URL: http://archimer.ifremer.fr/doc/1984/acte-975.pdf |
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| Keller, Kathrin M.; Joos, Fortunat; Raible, Christoph C.; Cocco, Valentina; Froelicher, Thomas L.; Dunne, John P.; Gehlen, Marion; Bopp, Laurent; Orr, James C.; Tjiputra, Jerry; Heinze, Christoph; Segschneider, Joachim; Roy, Tilla; Metzl, Nicolas. |
| Climate modes such as the North Atlantic Oscillation (NAO), representing internal variability of the climate system, influence the ocean carbon cycle and may mask trends in the sink of anthropogenic carbon. Here, utilising control runs of six fully coupled Earth System Models, the response of the ocean carbon cycle to the NAO is quantified. The dominating response, a seesaw pattern between the subtropical gyre and the subpolar Northern Atlantic, is instantaneous (<3 months) and dynamically consistent over all models and with observations for a range of physical and biogeochemical variables. All models show asymmetric responses to NAO+ and NAO− forcing, implying non-linearity in the connection between NAO and the ocean carbon cycle. However, model... |
| Tipo: Text |
Palavras-chave: North Atlantic Oscillation; Carbon cycle; Ocean biogeochemistry; Climate modeling; Ocean-atmosphere interaction. |
| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00140/25166/23272.pdf |
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| Registros recuperados: 36 | |
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