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| Registros recuperados: 36 | |
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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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| 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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| 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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| 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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| 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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| Reichardt, W. |
| The predominantly anoxic, sulfide-rich sandy sediment of a shallow lagoon at Kiel Fjord was densely inhabited by the polychaete worm Nereis diversicolor (280 cm super(3) m super(-2) of biomass volume). Burrow walls which contrasted by their brown coloration of at least 1.5 mm thickness with the bulk of the reduced black sediment, made up for 6% of the total volume of the 10 cm cores investigated. Only the uppermost mm of the internal surface layer contained detectable O sub(2). As a result of the build up of internal redox gradients, CO sub(2) dark fixation was activated in the burrow walls (by a factor of approximately equals 2). Assays of ribulose-biphosphate carboxylase activities and viable counts of potentially chemoautotrophic bacteria in different... |
| Tipo: Text |
Palavras-chave: Nereis diversicolor; Polychaeta; Bacteria; Microorganisms; Carbon cycle; Tube dwellers; Carbon fixation; Burrows; Bioturbation; Sediments. |
| Ano: 1984 |
URL: http://archimer.ifremer.fr/doc/1984/acte-990.pdf |
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| Skinner, Luke C.; Waelbroeck, Claire; Scrivner, Adam E.; Fallon, Stewart J.. |
| Recent theories for glacial-interglacial climate transitions call on millennial climate perturbations that purged the deep sea of sequestered carbon dioxide via a "bipolar ventilation seesaw." However, the viability of this hypothesis has been contested, and robust evidence in its support is lacking. Here we present a record of North Atlantic deep-water radiocarbon ventilation, which we compare with similar data from the Southern Ocean. A striking coherence in ventilation changes is found, with extremely high ventilation ages prevailing across the deep Atlantic during the last glacial period. The data also reveal two reversals in the ventilation gradient between the deep North Atlantic and Southern Ocean during Heinrich Stadial 1 and the Younger Dryas.... |
| Tipo: Text |
Palavras-chave: Ocean circulation; Carbon cycle; Abrupt change. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00290/40153/39327.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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| Laruelle, Goulven G.; Lauerwald, Ronny; Pfeil, Benjamin; Regnier, Pierre. |
| Over the past decade, estimates of the atmospheric CO2 uptake by continental shelf seas were constrained within the 0.18-0.45 Pg C yr(-1) range. However, most of those estimates are based on extrapolations from limited data sets of local flux measurements (n<100). Here we propose to derive the CO2 air-sea exchange of the shelf seas by extracting 310(6) direct surface ocean CO2 measurements from the global database SOCAT (Surface Ocean CO2 Atlas), atmospheric CO2 values from GlobalVIEW and calculating gas transfer rates using readily available global temperature, salinity, and wind speed fields. We then aggregate our results using a global segmentation of the shelf in 45 units and 152 subunits to establish a consistent regionalized CO2 exchange budget at... |
| Tipo: Text |
Palavras-chave: CO2; Coastal ocean; Carbon cycle. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00293/40426/38969.pdf |
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| Hauck, J.; Voelker, C.; Wang, T.; Hoppema, M.; Losch, M.; Wolf-gladrow, D. A.. |
| Stratospheric ozone depletion and emission of greenhouse gases lead to a trend of the southern annular mode (SAM) toward its high-index polarity. The positive phase of the SAM is characterized by stronger than usual westerly winds that induce changes in the physical carbon transport. Changes in the natural carbon budget of the upper 100 m of the Southern Ocean in response to a positive SAM phase are explored with a coupled ecosystem-general circulation model and regression analysis. Previously overlooked processes that are important for the upper ocean carbon budget during a positive SAM period are identified, namely, export production and downward transport of carbon north of the polar front (PF) as large as the upwelling in the south. The limiting... |
| Tipo: Text |
Palavras-chave: Southern Ocean; Southern annular mode; Carbon cycle; Carbon sink. |
| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00292/40352/38988.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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| 申, 宝明; 佐藤, 禎稔; 岸本, 正; 谷, 昌幸; 仙北谷, 康; 加藤, 拓; 林, 芙俊; SHEN, Baoming; SATOW, Tadatoshi; KISHIMOTO, Tadashi; TANI, Masayuki; SENBOKUYA, Yasushi; KATO, Taku; HAYASHI, Futoshi. |
| マニュアスプレッダによる堆肥の散布精度の現状を把握することを目的とし，横軸ピータ型，縦軸ビータ型，左側方散布型の3機種を対象として堆肥の散布量分布および 堆肥散布精度の調査を行った。各機種の散布量分布は，いずれも山型の形状を示しており，横軸ビータ型，縦軸ピータ型では，マニュアスプレッダの中心から左右1m以内に，それぞれ全体の76%，40%が散布され，左側方散布型は左側3-5mの範囲に全体の71%が集中して散布された。最大散布畳は横軸ビータ型が2.3t/l0a，縦軸ビータ型が6.5t/10a，左側方散布型が10.3t/l0aとなり，重複散布しても規定散布量である2t/l0aが望めない結果となった。また，圃場全体の堆肥散布量は各機種で0.2-3.4t/lOa，2.4-22. 8t/l0a，0.6-5.0t/10aであり， 堆肥の性状によって散布むらが大きくなることが判明した。The purpose of this study was to investigate the present situation of compost spreading with manure spreaders in Tokachi region. Therefore，three different types of manure spreaders: rear horizontal beater type(A)，vertical beater type (B) and side discharge type (C)，were used to determine the application pattern and accuracy of compost spreading. Application pattern of each... |
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Palavras-chave: 堆肥の利用; マッピング; 炭素循環; 精密農法; Utilization of compost; Mapping; Carbon cycle; Precision farming. |
| Ano: 2010 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2701 |
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| Registros recuperados: 36 | |
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