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| Doval, Md; Fraga, F; Perez, Ff. |
| An update of the Kjeldahl method is presented for the direct determination of dissolved organic nitrogen (DON) in seawater. Dissolved inorganic nitrogen is previously removed: ammonium as NH3 with NaOH at pH 9.4; and, subsequently, nitrate and nitrite as nitric oxide with FeSO4 in acid medium. The sample is then mineralized to ammonium, which is measured with a Technicon autoanalyzer by the indophenol blue method. The range of recovery for tested standard compounds is similar to those obtained by high temperature oxidation (HTO) techniques. Direct determination of DON by the method described in this work marks an improvement in precision, in comparison with other methods; the standard deviation obtained for samples of seawater is +/-0.2 mu mol.l(-1). The... |
| Tipo: Text |
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| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00093/20429/18096.pdf |
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| Lauvset, S. K.; Carter, B. R.; Perez, Ff; Jiang, L-q; Feely, R. A.; Velo, A.; Olsen, A.. |
| Ocean acidification evolves on the background of a natural ocean pH gradient that is the result of the interplay between ocean mixing, biological production and remineralization, calcium carbonate cycling, and temperature and pressure changes across the water column. While previous studies have analyzed these processes and their impacts on ocean carbonate chemistry, none have attempted to quantify their impacts on interior ocean pH globally. Here we evaluate how anthropogenic changes and natural processes collectively act on ocean pH, and how these processes set the vulnerability of regions to future changes in ocean acidification. We use the mapped data product from the Global Ocean Data Analysis Project version 2, a novel method to estimate preformed... |
| Tipo: Text |
Palavras-chave: PH; Remineralization; CaCO3; Anthropogenic; Global ocean. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00676/78793/81066.pdf |
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| Perez, Ff; Tokarczyk, R; Figueiras, Fg; Rios, Af. |
| This study - carried out between the Elephant and the Orkney islands - showed that spatial variability in the marginal ice-edge zone (MIZ) was greater than that found in open sea. Salinity and silicate contents point to the existence of two fronts: the first - near Elephant Island - separates the Surface Antarctic Water coming from Drake Passage from the winter water originating in the Weddell Sea. This water is characterized by its high concentrations of nitrate (> 30 mu M) and silicates (> 80 mu M). The second front - near the South Orkney Islands undergoes the influence by a less saline water lens (< 34 %), poor in nutrients (N-NO3 < 24 mu M) and rich in chlorophyll (> 3.5 mg Chl a 1(-1)). Water masses circulation reveals the existence of... |
| Tipo: Text |
Palavras-chave: MARGINAL ICE; WEDDELL SEA; WATER MASSES; NUTRIENTS; CHLOROPHYLL. |
| Ano: 1994 |
URL: http://archimer.ifremer.fr/doc/00098/20883/18497.pdf |
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| Perez, Ff; Alvarezsalgado, Xa; Roson, G; Rios, Af. |
| Biogenic element levels in continental runoff and their behaviour during estuarine mixing are studied in the Galician Rias Baixas for the upwelling season (May-October). Alkalinity, calcium, both with average concentrations of about 350 mumol.kg-1, and reactive silica, with 105 mumol.kg-1, show near conservative distributions along the estuarine side of the rias. A good agreement was found between values obtained by direct measurement in the river and those calculated by extrapolation to zero salinity from the mixing diagrams. On the other hand, nitrate (10-40 mumol.kg-1) and mainly phosphate (1 mumol.kg-1) are strongly affected by the biological activity of benthic algae during estuarine mixing. TON and ammonium in the innermost parts of the Ria de Arousa... |
| Tipo: Text |
Palavras-chave: BIOGENIC ELEMENTS; TON; RUNOFF; ESTUARINE MIXING; RIAS-BAIXAS. |
| Ano: 1992 |
URL: http://archimer.ifremer.fr/doc/00101/21184/18801.pdf |
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| Cossa, Daniel; Heimburger, L. E.; Sonke, J. E.; Planquette, H.; Lherminier, Pascale; Garcia-ibanez, Maria Isabel; Perez, Ff; Sarthou, G.. |
| The Labrador Sea links the Arctic and North Atlantic oceans and constitutes one of the main entrances of atmospheric inputs into the Ocean's interior. We report here the first high-resolution Hg distribution pattern along a transect from Greenland to Labrador coasts sampled after the 2014 winter convection. Total Hg concentrations in unfiltered (HgTUNF) samples ranged from 0.25 pmol L− 1 to 0.67 pmol L− 1 averaging 0.44 ± 0.10 pmol L− 1 (n = 113, 1σ). Concentrations in filtered samples (HgTF, < 0.45 μm) represented from 62 to 92% of the HgTUNF and exhibited a similar distribution. High HgTUNF concentrations were found (i) in the waters of the Labrador Current, which receive desalted waters from the Canadian Arctic Archipelago, and (ii) in the waters... |
| Tipo: Text |
Palavras-chave: Labrador Sea; Mercury; North Atlantic. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00411/52207/52929.pdf |
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| Zunino Rodriguez, Patricia; Garcia-ibanez, Maria Isabel; Lherminier, Pascale; Mercier, Herle; Rios, A. F.; Perez, Ff. |
| The interannual to decadal variability in the transport of anthropogenic CO2 (Cant) across the subpolar North Atlantic (SPNA) is investigated, using summer data of the FOUREX and OVIDE high-resolution transoceanic sections, from Greenland to Portugal, occupied six times from 1997 to 2010. The transport of Cant across this section, T-cant hereafter, is northward, with a mean value of 254 +/- 29 kmol s(-)1 over the 1997-2010 period. We find that T-cant undergoes interannual variability, masking any trend different from 0 for this period. In order to understand the mechanisms controlling the variability of T-cant across the SPNA, we propose a new method that quantifies the transport of Cant caused by the diapycnal and isopycnal circulation. The diapycnal... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00192/30317/28792.pdf |
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| Fajar, N. M.; Pardo, P. C.; Carracedo, Lidia; Vazquez-rodriguez, M.; Rios, A. F.; Perez, Ff. |
| The carbon system in the water masses of the Iberian Basin (North Atlantic Ocean) has been affected over the last two decades by the increase in anthropogenic CO2 (C-ant). In order to study the storage of C-ant in the Iberian Basin, variables of the carbonic system (i.e., pH, total inorganic carbon, and total alkalinity), among others, were measured during the CAIBOX cruise conducted between July and August 2009 within the framework of the CAIBEX project (Shelf-Ocean Exchanges in the Canary-Iberian Large Marine Ecosystem). The storage of C-ant was estimated using two different back-calculation techniques (i.e., the phi C degrees(T) and TrOCA methods) and for six layers of the water column corresponding to the approximate locations of the characteristic... |
| Tipo: Text |
Palavras-chave: Anthropogenic CO2; Back-calculation. |
| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00629/74112/73546.pdf |
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