Consulta: creatorFacets:"Fontela, Marcos"
Registros recuperados: 6
Data/hora: 09/06/2024 10:48:30

Cold-water corals in the Subpolar North Atlantic Ocean exposed to aragonite undersaturation if the 2 °C global warming target is not met
Provedor de dados: 5
Autores: García-ibáñez, Maribel I.; Bates, Nicholas R.; Bakker, Dorothee C.e.; Fontela, Marcos; Velo, Antón.
The net uptake of carbon dioxide (CO2) from the atmosphere is changing the ocean's chemical state. Such changes, commonly known as ocean acidification, include a reduction in pH and the carbonate ion concentration ([CO32−]), which in turn lowers oceanic saturation states (Ω) for calcium carbonate (CaCO3) minerals. The Ω values for aragonite (Ωaragonite; one of the main CaCO3 minerals formed by marine calcifying organisms) influence the calcification rate and geographic distribution of cold-water corals (CWCs), important for biodiversity. Here, high-quality measurements, collected on thirteen cruises along the same track during 1991–2018, are used to determine the long-term changes in Ωaragonite in the Irminger and Iceland Basins of the North Atlantic...
Tipo: Text
Palavras-chave: Ocean acidification; Aragonite saturation state; Atlantic Meridional Overturning Circulation; Eastern-Subpolar North Atlantic Ocean.
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00688/79965/82895.pdf

North Atlantic Western Boundary Currents Are Intense Dissolved Organic Carbon Streams
Provedor de dados: 5
Autores: Fontela, Marcos; Pérez, Fiz F; Mercier, Herle; Lherminier, Pascale.
In the North Atlantic, there are two main western boundary currents related to the Atlantic Meridional Overturning Circulation (AMOC): the Gulf Stream flowing northward and the Deep Western Boundary Current (DWBC) flowing southward. Here we analyze data from the OVIDE section (GO-SHIP A25 Portugal-Greenland 40–60°N) that crosses the DWBC and the northward extension of the Gulf Stream, the North Atlantic Current. We show that North Atlantic western boundary currents play a key role in the transport of dissolved organic matter, specifically dissolved organic carbon (DOC). Revisited transports and budgets of DOC with new available data identify the eastern Subpolar North Atlantic (eSPNA) as an important source of locally produced organic matter for the North...
Tipo: Text
Palavras-chave: Dissolved organic carbon; North Atlantic; Carbon budget; Carbon dioxide; Biogeochemistry; Atlantic Meridional Overturning Circulation.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00661/77268/78702.pdf

Dissolved Organic Carbon in the North Atlantic Meridional Overturning Circulation
Provedor de dados: 5
Autores: Fontela, Marcos; Garcia-ibanez, Maria Isabel; Hansell, Dennis A.; Mercier, Herle; Perez, Fiz F.
The quantitative role of the Atlantic Meridional Overturning Circulation (AMOC) in dissolved organic carbon (DOC) export is evaluated by combining DOC measurements with observed water mass transports. In the eastern subpolar North Atlantic, both upper and lower limbs of the AMOC transport high-DOC waters. Deep water formation that connects the two limbs of the AMOC results in a high downward export of non-refractory DOC (197 Tg-C center dot yr(-1)). Subsequent remineralization in the lower limb of the AMOC, between subpolar and subtropical latitudes, consumes 72% of the DOC exported by the whole Atlantic Ocean. The contribution of DOC to the carbon sequestration in the North Atlantic Ocean (62 Tg-C center dot yr(-1)) is considerable and represents almost a...
Tipo: Text
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00342/45298/44754.pdf

Long-term integrated biogeochemical budget driven by circulation in the eastern subpolar North Atlantic
Provedor de dados: 5
Autores: Fontela, Marcos; Mercier, Herle; Pérez, Fiz F.
The eastern subpolar North Atlantic (eSPNA) is a key region in the Atlantic Meridional Overturning Circulation (AMOC), playing an important role in biogeochemical cycles and climate regulation. Quantitative basin-scale biogeochemical budgets are still scarce despite the current need of establishing baselines of knowledge in a changing ocean. The physico-chemical data from the eight repetitions of the OVIDE section (2002-2016) are an unique opportunity to develop a novel evaluation of biogeochemical budgets in the eSPNA by combining robust and well established decadal mean mass transports with carbon variables, oxygen and inorganic nutrients in a full-depth inverse box model. The net balance between the carbon fixation and the respiration throughout the...
Tipo: Text
Palavras-chave: Subpolar North Atlantic; Biogeochemical cycles; Carbon cycle; Nutrient cycles; Oxygenation; Carbon sinks; Oceanic transports.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00480/59206/61898.pdf

The Northeast Atlantic is running out of excess carbonate in the horizon of cold-water corals communities
Provedor de dados: 5
Autores: Fontela, Marcos; Perez, Fiz F; Carracedo, Lidia; Padín, Xosé A.; Velo, Antón; García-ibañez, Maribel I.; Lherminier, Pascale.
The oceanic uptake of atmospheric carbon dioxide (CO2) emitted by human activities alters the seawater carbonate system. Here, the chemical status of the Northeast Atlantic is examined by means of a high-quality database of carbon variables based on the GO-SHIP A25 section (1997–2018). The increase of atmospheric CO2 leads to an increase in ocean anthropogenic carbon (Cant) and a decrease in carbonate that is unequivocal in the upper and mid-layers (0–2,500 m depth). In the mid-layer, the carbonate content in the Northeast Atlantic is maintained by the interplay between the northward spreading of recently conveyed Mediterranean Water with excess of carbonate and the arrival of subpolar-origin waters close to carbonate undersaturation. In this study we show...
Tipo: Text
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00646/75822/76790.pdf

Meridional overturning circulation conveys fast acidification to the deep Atlantic Ocean
Provedor de dados: 5
Autores: Perez, Fiz F; Fontela, Marcos; Garcia-ibanez, Maria Isabel; Mercier, Herle; Velo, Anton; Lherminier, Pascale; Zunino, Patricia; De La Paz, Mercedes; Alonso-perez, Fernando; Guallart, Elisa E.; Padin, Xose A.
Since the Industrial Revolution, the North Atlantic Ocean has been accumulating anthropogenic carbon dioxide (CO2) and experiencing ocean acidification1, that is, an increase in the concentration of hydrogen ions (a reduction in pH) and a reduction in the concentration of carbonate ions. The latter causes the ‘aragonite saturation horizon’—below which waters are undersaturated with respect to a particular calcium carbonate, aragonite—to move to shallower depths (to shoal), exposing corals to corrosive waters2,3. Here we use a database analysis to show that the present rate of supply of acidified waters to the deep Atlantic could cause the aragonite saturation horizon to shoal by 1,000–1,700 metres in the subpolar North Atlantic within the next three...
Tipo: Text
Ano: 2018
URL: http://archimer.ifremer.fr/doc/00426/53783/55106.pdf