23 results on '"Santana-Casiano, M."'
Search Results
2. The role of tides and sea ice on the carbonate chemistry in a coastal polynya in the south-eastern Weddell Sea
- Author
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Droste, E., Bakker, D., Hoppema, Mario, González-Dávila, M., Santana-Casiano, M., Rohardt, Gerd, Dall'Olmo, G., Queste, B., Venables, H., Droste, E., Bakker, D., Hoppema, Mario, González-Dávila, M., Santana-Casiano, M., Rohardt, Gerd, Dall'Olmo, G., Queste, B., and Venables, H.
- Published
- 2022
3. The role of tides in the carbonate chemistry of a coastal polynya in the Weddell Sea: a case study for PICCOLO
- Author
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Droste, E., Bakker, D. C. E., Hoppema, Mario, González-Dávila, M., Santana-Casiano, M., Rohardt, Gerd, Dall'Olmo, G., Queste, B., Venables, H., Droste, E., Bakker, D. C. E., Hoppema, Mario, González-Dávila, M., Santana-Casiano, M., Rohardt, Gerd, Dall'Olmo, G., Queste, B., and Venables, H.
- Published
- 2021
4. The Role of Tides on the Carbon Uptake of a Coastal Polynya in the Weddell Sea
- Author
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Droste, E., Bakker, D., Hoppema, Mario, González-Dávila, M., Santana Casiano, M., Rohardt, Gerd, Droste, E., Bakker, D., Hoppema, Mario, González-Dávila, M., Santana Casiano, M., and Rohardt, Gerd
- Published
- 2020
5. Coupling between the open ocean and the coastal upwelling region off northwest Africa: water recirculation and offshore pumping of organic matter
- Author
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Pelegrí, J.L., Arístegui, J., Cana, L., González-Dávila, M., Hernández-Guerra, A., Hernández-León, S., Marrero-Díaz, A., Montero, M.F., Sangrà, P., and Santana-Casiano, M.
- Published
- 2005
- Full Text
- View/download PDF
6. Changes during a 40 years period in storage of anthropogenic carbon and ventilation in the Atlantic sector of the Southern Ocean
- Author
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Tanhua, T., Hoppema, Mario, Jones, E.M., Stöven, T., Hauck, Judith, González-Dávila, M., Santana-Casiano, M., Álvarez, M., Strass, Volker H., Tanhua, T., Hoppema, Mario, Jones, E.M., Stöven, T., Hauck, Judith, González-Dávila, M., Santana-Casiano, M., Álvarez, M., and Strass, Volker H.
- Published
- 2017
7. Estoc: New approach warrants long-term support to the oceanic observational program
- Author
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Cianca, A, Santana, R., Delory, E., Remirez, X., Barrera, C., Llerandi, C., Cardona, L., Villagarcia, M., Vega, D., Gonzáles Dávila, M., Santana Casiano, M., Rueda, MJ., and Llinas, O.
- Subjects
education - Published
- 2011
8. The EuroSITES open ocean observatory network: the data managers' perspective
- Author
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Pangnani, M., Lampitt, R., Larkin, K., Hartman, S., Campbell, J., Pebody, C., Ruhl, H., Billett, D., Hühnerbach, V., Masson, D., Osterhus, S., Skjelvan, I., Lykousis, V., Nittis, K., Perivoliotis, L., Kassis, D., Petihakis, G., Cardin, V., Bensi, M., Brunetti, F., Giorgetti, A., Bozzano, R., Pensieri, S., Wallace, Douglas W.R., Karstensen, Johannes, Berndt, Christian, Priede, I., Holford, A., Niedzielski, T., Hastie, L., Jamieson, A., Coppola, L., Tamburini, C., Lefevre, D., Robert, A., Pouliquen, S., Carval, T., Ghiron, G., Llinas-Gonzolez, O., Cianca, A., Melicio, O., Santos, C., Medina, A., Silva, P., Monteiro, I., Gonzalez-Davila, M., and Santana-Casiano, M.
- Abstract
The EuroSITES project was funded within the EU framework 7 to aid the convergence of the efforts of the 11 European-wide deep ocean observatories which formed its core. A major output of the project was envisaged as the synergies of the 13 partners working together to create a network providing sets of data in near-real-time, and in delayed-mode, which have been collected and processed in such a way as to be accessible to the wider scientific community, and comparable across time and site. The common data policy agreed by all the partners at the start of the project, and the evolution of a EuroSITES quality control manual which includes all the observatories practices, have formed the framework within which each data management group has delivered datasets which now carry the EuroSITES 'brand' as well as all the originators details. As a focal point for the, currently, 12 sites the EuroSITES data managers have worked as the European partner within the international OceanSITES project, developing the OceanSITES distribution standard, and studying the options for attaching additional metadata to data sets. The influence of EuroSITES as the European champion for the distribution of data in OceanSITES format will be an enduring legacy. The EuroSITES website (www.eurosites.info) provides a highly visible, and user accessible platform for the distribution of near-real time data from the observatories, as it becomes available. The data from the diverse sites are displayed in a consistent manner and the web pages form a coherent 'shop window' where potential data users can source data sets useful to their research, as well as a visual means of monitoring the health of the observatories. The sister site (outreach.eurosites.info) has been developed in parallel to be accessible to non-scientists. Working together EuroSITES has been able to develop a single conversion software package taking MEDATLAS and ODV ascii files and outputting the OceanSITES format. The sharing of knowledge in this and other developments ensures that costly duplication of effort is minimised. During the 3 years of the project the data management groups have interacted to share best practice, and although each is still independent and serves its own National Data Centre, the EuroSITES data inventory now carries data from all 13 sites, distributed in the OceanSITES v1.2 format. This format is NetCDF based, and carries within the file metadata. This describes the data in a consistent manner which achieves the first step towards interoperablility. The future of the funding of EuroSITES after April 2011 is not yet clear, but the project has achieved a remarkable degree of harmonisation already, and the relationships between the data management groups will undoubtedly continue as the cost benefits of resource and knowledge sharing become ever more important in the scientific arena.
- Published
- 2011
9. Estimating the monthly pCO2 distribution in the North Atlantic using a self-organizing neural network
- Author
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Telszewski, M., Chazottes, A., Schuster, U., Watson, A. J., Moulin, C., Bakker, D. C. E., González-Dávila, M., Johannessen, T., Körtzinger, A., Lüger, H., Olsen, A., Omar, A., Padin, X. A., Ríos, A. F., Tobias Steinhoff, Santana-Casiano, M., Wallace, D. W. R., Wanninkhof, R., Laboratoire des Sciences du Climat et de l'Environnement (LSCE), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
- Subjects
lcsh:Geology ,lcsh:QH501-531 ,[SDU]Sciences of the Universe [physics] ,lcsh:QH540-549.5 ,lcsh:QE1-996.5 ,lcsh:Life ,Earth Science ,lcsh:Ecology - Abstract
Here we present monthly, basin-wide maps of the partial pressure of carbon dioxide (pCO2) for the North Atlantic on a 1° latitude by 1° longitude grid for years 2004 through 2006 inclusive. The maps have been computed using a neural network technique which reconstructs the non-linear relationships between three biogeochemical parameters and marine pCO2. A self organizing map (SOM) neural network has been trained using 389 000 triplets of the SeaWiFS-MODIS chlorophyll-a concentration, the NCEP/NCAR reanalysis sea surface temperature, and the FOAM mixed layer depth. The trained SOM was labelled with 137 000 underway pCO2 measurements collected in situ during 2004, 2005 and 2006 in the North Atlantic, spanning the range of 208 to 437 μatm. The root mean square error (RMSE) of the neural network fit to the data is 11.6 μatm, which equals to just above 3 per cent of an average pCO2 value in the in situ dataset. The seasonal pCO2 cycle as well as estimates of the interannual variability in the major biogeochemical provinces are presented and discussed. High resolution combined with basin-wide coverage makes the maps a useful tool for several applications such as the monitoring of basin-wide air-sea CO2 fluxes or improvement of seasonal and interannual marine CO2 cycles in future model predictions. The method itself is a valuable alternative to traditional statistical modelling techniques used in geosciences.
- Published
- 2009
10. Estimating the monthly pCO2 distribution in the North Atlantic using a self-organizing neural network
- Author
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Telszewski, A. Chazottes, Schuster, U., Watson, A. J., Moulin, C., Bakker, D. C. E., González-Dávila, M., Johannessen, T., Körtzinger, Arne, Lüger, H., Olsen, A., Omar, A., Padin, X. A., Ríos, A. F., Steinhoff, Tobias, Santana-Casiano, M., Wallace, Douglas W.R., and Wanninkhof, R.
- Abstract
Here we present monthly, basin-wide maps of the partial pressure of carbon dioxide (pCO2) for the North Atlantic on a 1° latitude by 1° longitude grid for years 2004 through 2006 inclusive. The maps have been computed using a neural network technique which reconstructs the non-linear relationships between three biogeochemical parameters and marine pCO2. A self organizing map (SOM) neural network has been trained using 389 000 triplets of the SeaWiFS-MODIS chlorophyll-a concentration, the NCEP/NCAR reanalysis sea surface temperature, and the FOAM mixed layer depth. The trained SOM was labelled with 137 000 underway pCO2 measurements collected in situ during 2004, 2005 and 2006 in the North Atlantic, spanning the range of 208 to 437 μatm. The root mean square error (RMSE) of the neural network fit to the data is 11.6 μatm, which equals to just above 3 per cent of an average pCO2 value in the in situ dataset. The seasonal pCO2 cycle as well as estimates of the interannual variability in the major biogeochemical provinces are presented and discussed. High resolution combined with basin-wide coverage makes the maps a useful tool for several applications such as the monitoring of basin-wide air-sea CO2 fluxes or improvement of seasonal and interannual marine CO2 cycles in future model predictions. The method itself is a valuable alternative to traditional statistical modelling techniques used in geosciences.
- Published
- 2009
11. SOCAT Data treatment and adjustments
- Author
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Pfeil, B., Olsen, A., Bakker, D. C. E., Sabine, C., Metzl, N., Kozyr, A., Borges, A., Schuster, U., Telszewski, M., Chen, A., Tilbrook, B., Sarma, V. V. S. S., Feely, R., Wanninkhof, R., Hankin, S., Koyuk, H., Malczyk, J., Tedesco, K., Cosca, C., Miyazaki, C., Hunt, C., Pierrot, D., Park, G. H., Skjelvan, I., Paterson, K., Santana-Casiano, M., Hood, M., Hoppema, Mario, Watson, A., Lourantou, A., Padin, A., Lefevre, N., Hardman-Mountford, N., Omar, A., Nakaoka, S., Alin, S., Steinhoff, T., Suzuki, T., Johannessen, T., Nakana, Y., Nojiri, Y., Pfeil, B., Olsen, A., Bakker, D. C. E., Sabine, C., Metzl, N., Kozyr, A., Borges, A., Schuster, U., Telszewski, M., Chen, A., Tilbrook, B., Sarma, V. V. S. S., Feely, R., Wanninkhof, R., Hankin, S., Koyuk, H., Malczyk, J., Tedesco, K., Cosca, C., Miyazaki, C., Hunt, C., Pierrot, D., Park, G. H., Skjelvan, I., Paterson, K., Santana-Casiano, M., Hood, M., Hoppema, Mario, Watson, A., Lourantou, A., Padin, A., Lefevre, N., Hardman-Mountford, N., Omar, A., Nakaoka, S., Alin, S., Steinhoff, T., Suzuki, T., Johannessen, T., Nakana, Y., and Nojiri, Y.
- Published
- 2011
12. The EuroSITES open ocean observatory network: Results and future vision
- Author
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Lampitt, R., Larkin, K., Hartman, S., Gkritzalis, A., Pagnani, M., Pebody, C., Ruhl, H., Billett, D., Hühnerbach, V., Masson, D., Osterhus, S., Nittis, K., Lykousis, V., Petihakis, G., Cardin, V., Bensi, M., Brunetti, F., Bozzano, R., Pensieri, S., Wallace, Douglas W.R., Karstensen, Johannes, Berndt, Christian, Priede, I., Holford, A., Niedzielski, T., Hastie, L., Jamieson, A., Coppola, L., Tamburini, C., Lefevre, D., Robert, A., Pouliquen, S., Carval, T., Ghiron, G., Llinas-Gonzolez, O., Cianca, A., Melicio, O., Santos, C., Medina, A., Silva, P., Monteiro, I., Gonzalez-Davila, M., Santana-Casiano, M., Lampitt, R., Larkin, K., Hartman, S., Gkritzalis, A., Pagnani, M., Pebody, C., Ruhl, H., Billett, D., Hühnerbach, V., Masson, D., Osterhus, S., Nittis, K., Lykousis, V., Petihakis, G., Cardin, V., Bensi, M., Brunetti, F., Bozzano, R., Pensieri, S., Wallace, Douglas W.R., Karstensen, Johannes, Berndt, Christian, Priede, I., Holford, A., Niedzielski, T., Hastie, L., Jamieson, A., Coppola, L., Tamburini, C., Lefevre, D., Robert, A., Pouliquen, S., Carval, T., Ghiron, G., Llinas-Gonzolez, O., Cianca, A., Melicio, O., Santos, C., Medina, A., Silva, P., Monteiro, I., Gonzalez-Davila, M., and Santana-Casiano, M.
- Published
- 2011
13. EuroSITES European network of deep ocean observatories
- Author
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Dahlin, H., Bell, M.J., Flemming, N.C., Petersson, S.E., Lampitt, R.S., Larkin, K.E., Hartman, S.E., Pagnani, M.R., Billett, D.S.M., Berndt, C., Huhnerbach, V., Osterhus, S., Nittis, K., Lykousis, V., Petihakis, G., Cardin, V., Brunetti, F., Bozzano, R., Pensieri, S., Wallace, D., Karstensen, J., Cotrim da Cunha, L., Priede, I.G., Holford, A., Coppola, L., Tamburini, C., Lefevre, D., Poulinquen, S., Carval, T., Ghiron, S., Llindis-Gonzalez, O., Cianca, A., Melicio, O., Santos, C., Silva, P., Gonzalez-Davila, M., Santana-Casiano, M., Dahlin, H., Bell, M.J., Flemming, N.C., Petersson, S.E., Lampitt, R.S., Larkin, K.E., Hartman, S.E., Pagnani, M.R., Billett, D.S.M., Berndt, C., Huhnerbach, V., Osterhus, S., Nittis, K., Lykousis, V., Petihakis, G., Cardin, V., Brunetti, F., Bozzano, R., Pensieri, S., Wallace, D., Karstensen, J., Cotrim da Cunha, L., Priede, I.G., Holford, A., Coppola, L., Tamburini, C., Lefevre, D., Poulinquen, S., Carval, T., Ghiron, S., Llindis-Gonzalez, O., Cianca, A., Melicio, O., Santos, C., Silva, P., Gonzalez-Davila, M., and Santana-Casiano, M.
- Published
- 2010
14. Sea surface pCO2 and air-sea flux maps of the North Atlantic for 2004 to 2006 using neural networks
- Author
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Telszewski, M., Chazottes, A., Schuster, U., Watson, A.J., Moulin, C., Bakker, D., Olsen, A., Johannessen, T., Omar, A., Rios, A., Pérez, F., Lüger, H., Körtzinger, Arne, Steinhoff, Tobias, Wallace, Douglas W.R., González-Dávila, M., Santana-Casiano, M., Wanninkhof, R., Telszewski, M., Chazottes, A., Schuster, U., Watson, A.J., Moulin, C., Bakker, D., Olsen, A., Johannessen, T., Omar, A., Rios, A., Pérez, F., Lüger, H., Körtzinger, Arne, Steinhoff, Tobias, Wallace, Douglas W.R., González-Dávila, M., Santana-Casiano, M., and Wanninkhof, R.
- Published
- 2008
15. Estimating the monthly <i>p</i>CO<sub>2</sub> distribution in the North Atlantic using a self-organizing neural network
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Telszewski, M., primary, Chazottes, A., additional, Schuster, U., additional, Watson, A. J., additional, Moulin, C., additional, Bakker, D. C. E., additional, González-Dávila, M., additional, Johannessen, T., additional, Körtzinger, A., additional, Lüger, H., additional, Olsen, A., additional, Omar, A., additional, Padin, X. A., additional, Ríos, A. F., additional, Steinhoff, T., additional, Santana-Casiano, M., additional, Wallace, D. W. R., additional, and Wanninkhof, R., additional
- Published
- 2009
- Full Text
- View/download PDF
16. Trends in North Atlantic sea-surface fCO2 from 1990 to 2006
- Author
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Schuster, U., primary, Watson, A.J., additional, Bates, N.R., additional, Corbiere, A., additional, Gonzalez-Davila, M., additional, Metzl, N., additional, Pierrot, D., additional, and Santana-Casiano, M., additional
- Published
- 2009
- Full Text
- View/download PDF
17. Mixing analysis of nutrients, oxygen and inorganic carbon in the Canary Islands region
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Pérez, Fiz F., Mintrop, Ludger, Llinás, O., Glez-Dávila, M., Castro, C. G., Alvarez, M., Körtzinger, Arne, Santana-Casiano, M., Rueda, M. J., Ríos, A. F., Pérez, Fiz F., Mintrop, Ludger, Llinás, O., Glez-Dávila, M., Castro, C. G., Alvarez, M., Körtzinger, Arne, Santana-Casiano, M., Rueda, M. J., and Ríos, A. F.
- Abstract
We show the distribution of nutrients, oxygen, total dissolved inorganic carbon (CT) and total alkalinity (AT) along three sections close to the Canary Islands, between 18°W and the African coast during Meteor 37/2 cruise (January 1997). From the thermohaline properties of Eastern North Atlantic Central Water (ENACW), Mediterranean Water (MW), Antarctic Intermediate Water (AAIW) and North Atlantic Deep Water (NADW), a mixing model has been established based on the water mass description. It can explain most of the variabilities found in the distribution of the chemical variables, including the carbon system, and it is validated through the use of conservative chemical variables like ‘NO.’ From nutrients, oxygen, AT and CT, the chemical characterisation of the water masses was performed by calculating the concentration of these variables in the previously defined thermohaline end-members. The relative variation of nutrient concentrations, resulting from the regeneration of organic matter, was estimated. Close to the African shelf-break, a poleward undercurrent conveying as much as a 11% of AAIW was observed only in the southern section (28.5°N). From the chemical and thermohaline properties of the end-members, a comparison with data from other oceanic regions was made in respect to conservative chemical variables (‘NO’). In addition, a north–south gradient in the ventilation pattern of water masses is observed from the residuals of the model.
- Published
- 2001
- Full Text
- View/download PDF
18. Estimating the monthly pCO2 distribution in the North Atlantic using a self-organizing neural network.
- Author
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Telszewski, M., Chazottes, A., Schuster, U., Watson, A. J., Moulin, C., Bakker, D. C. E., González-Dávila, M., Johannessen, T., Körtzinger, A., Lüger, H., Olsen, A., Omar, A., Padin, X. A., Ríos, A. F., Steinhoff, T., Santana-Casiano, M., Wallace, D. W. R., and Wanninkhof, R.
- Subjects
CARBON dioxide ,CHLOROPHYLL ,BIOGEOGRAPHY ,ARTIFICIAL neural networks ,SELF-organizing maps - Abstract
Here we present monthly, basin-wide maps of the partial pressure of carbon dioxide (pCO
2 ) for the North Atlantic on a 1° latitude by 1° longitude grid for years 2004 through 2006 inclusive. The maps have been computed using a neural network technique which reconstructs the non-linear relationships between three biogeochemical parameters and marine pCO2 . A self organizing map (SOM) neural network has been trained using 389 000 triplets of the SeaWiFSMODIS chlorophyll-a concentration, the NCEP/NCAR reanalysis sea surface temperature, and the FOAM mixed layer depth. The trained SOM was labelled with 137 000 underway pCO2 measurements collected in situ during 2004, 2005 and 2006 in the North Atlantic, spanning the range of 208 to 437 μatm. The root mean square error (RMSE) of the neural network fit to the data is 11.6 μatm, which equals to just above 3 per cent of an average pCO2 value in the in situ dataset. The seasonal pCO2 cycle as well as estimates of the interannual variability in the major biogeochemical provinces are presented and discussed. High resolution combined with basin-wide coverage makes the maps a useful tool for several applications such as the monitoring of basin-wide air-sea CO2 fluxes or improvement of seasonal and interannual marine CO2 cycles in future model predictions. The method itself is a valuable alternative to traditional statistical modelling techniques used in geosciences. [ABSTRACT FROM AUTHOR]- Published
- 2009
- Full Text
- View/download PDF
19. Dissolved/Dispersed Hydrocarbons in Sea Water, Determined by Infrared and Fluorescence Spectroscopy.
- Author
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Gonzalez-davila, M., Perez-Peña, J., Santana-casiano, M., and Hernandez-brito, J.
- Published
- 1989
- Full Text
- View/download PDF
20. Estimating the monthly pCO2 distribution in the north Atlantic using a self-organizing neural network
- Author
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Telszewski, M., Chazottes, A., Schuster, U., Watson, Aj, Moulin, C., Bakker, Dce, Gonzalez-Davila, M., Johannessen, T., Kortzinger, A., Luger, H., Are Olsen, Omar, A., Padin, Xa, Rios, Af, Steinhoff, T., Santana-Casiano, M., Wallace, Dwr, Wanninkhof, R., School of Environmental Sciences [Norwich], University of East Anglia [Norwich] (UEA), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Las Palmas de Gran Canaria [Espagne] (ULPGC), Geophysical Institute [Bergen] (GFI / BiU), University of Bergen (UiB), Leibniz Institute of Marine Science at the University of Kiel (IFM-GEOMAR), Kiel University, NOAA Atlantic Oceanographic and Meteorological Laboratory (AOML), National Oceanic and Atmospheric Administration (NOAA), Bjerknes Centre for Climate Research (BCCR), Department of Biological Sciences [Bergen] (BIO / UiB), University of Bergen (UiB)-University of Bergen (UiB), Analytical and Marine Chemistry, Göteborgs Universitet (GU), Spanish National Research Council (CSIC), the Spanish project ICCABA CTM2005-03893/MAR, the Norwegian Research Council through A-CARB (178167) and CARBON-HEAT (185093), the Swedish National Space Board through RESCUE – II, European Project: 30029,CARBOOCEAN, European Project: 238366,EC:FP7:PEOPLE,FP7-PEOPLE-ITN-2008,GREENCYCLESII(2010), European Project: 693594,H2020,ERC-2015-PoC,EndoNaut(2016), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)
- Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere ,[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment - Abstract
Here we present monthly, basin-wide maps of the partial pressure of carbon dioxide (pCO2) for the North Atlantic on a 1° latitude by 1° longitude grid for years 2004 through 2006 inclusive. The maps have been computed using a neural network technique which reconstructs the non-linear relationships between three biogeochemical parameters and marine pCO2. A self organizing map (SOM) neural network has been trained using 389 000 triplets of the SeaWiFS-MODIS chlorophyll-a concentration, the NCEP/NCAR reanalysis sea surface temperature, and the FOAM mixed layer depth. The trained SOM was labelled with 137 000 underway pCO2 measurements collected in situ during 2004, 2005 and 2006 in the North Atlantic, spanning the range of 208 to 437 μatm. The root mean square error (RMSE) of the neural network fit to the data is 11.6 μatm, which equals to just above 3 per cent of an average pCO2 value in the in situ dataset. The seasonal pCO2 cycle as well as estimates of the interannual variability in the major biogeochemical provinces are presented and discussed. High resolution combined with basin-wide coverage makes the maps a useful tool for several applications such as the monitoring of basin-wide air-sea CO2 fluxes or improvement of seasonal and interannual marine CO2 cycles in future model predictions. The method itself is a valuable alternative to traditional statistical modelling techniques used in geosciences.
21. Trends in North Atlantic sea-surface fCO2 from 1990 to 2006
- Author
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Schuster, U., Watson, A.J., Bates, N.R., Corbiere, A., Gonzalez-Davila, M., Metzl, N., Pierrot, D., and Santana-Casiano, M.
- Subjects
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CARBON dioxide in seawater , *OCEANOGRAPHIC observations , *OCEANOGRAPHIC research ships , *ATMOSPHERIC carbon dioxide , *OCEAN temperature , *SEASONAL variations in biogeochemical cycles , *OCEAN circulation , *LATITUDE - Abstract
Abstract: We examine observations from 1990 to 2006 from four voluntary observing ships and two time-series stations in the North Atlantic, fitting a sinusoidal annual cycle and linear year-on-year trend at all locations where there are sufficient data. Results show that in the subtropical regions, sea-surface fCO2 has closely followed the increasing trend in atmospheric fCO2. In contrast, farther north, sea-surface fCO2 has increased faster than fCO2 in the atmosphere. The resulting ΔfCO2, driving air–sea flux of CO2, has therefore decreased in the North Atlantic, particularly at higher latitudes, as has the annual mean air–sea flux. Several underlying causes may have led to the observed changes in sea-surface fCO2. Low-frequency modes, such as the North Atlantic Oscillation, lead to changes in the sea-surface temperature, in sea-surface circulation and in vertical mixing, affecting sea-surface fCO2 through biogeochemical processes. A comparison with measurements covering a longer time period shows that the sea-surface fCO2 rise has accelerated since 1990 in the northern North Atlantic. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
22. Copper toxicity leads to accumulation of free amino acids and polyphenols in Phaeodactylum tricornutum diatoms.
- Author
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Santiago-Díaz P, Rivero A, Rico M, González González A, González-Dávila M, and Santana-Casiano M
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- Antioxidants pharmacology, Copper chemistry, Amino Acids, Histidine pharmacology, Gallic Acid pharmacology, Methionine, Polyphenols pharmacology, Diatoms
- Abstract
This work is focused on the effect of lethal and sub-lethal copper (Cu) concentrations on the free amino acid and polyphenol production by the marine diatom Phaeodactylum tricornutum (P. tricornutum) after 12, 18, and 21 days of exposure. The concentrations of 10 amino acids (arginine, aspartic acid, glutamic acid, histidine, lysine, methionine, proline, valine, isoleucine, and phenylalanine) and 10 polyphenols (gallic acid, protocatechuic acid, p-coumaric acid, ferulic acid, catechin, vanillic acid, epicatechin syringic acid, rutin, and gentisic acid) were measured by RP-HPLC. Under lethal doses of Cu, free amino acids reached levels significantly higher than those in the control cells (up to 21.9 times higher), where histidine and methionine showed the highest increases (up to 37.4 and 65.8 times higher, respectively). The total phenolic content also increased up to 11.3 and 5.59 times higher compared to the reference cells, showing gallic acid the highest increase (45.8 times greater). The antioxidant activities of cells exposed to Cu were also enhanced with increasing doses of Cu(II). They were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging ability (RSA), cupric ion reducing antioxidant capacity (CUPRAC), and ferric reducing antioxidant power (FRAP) assays. Malonaldehyde (MDA) exhibited the same tendency: cells grown at the highest lethal Cu concentration yielded the highest MDA level. These findings reflect the involvement of amino acids and polyphenols in protective mechanisms to overcome the toxicity of copper in marine microalgae., (© 2023. The Author(s).)
- Published
- 2023
- Full Text
- View/download PDF
23. Bioactive Metabolites of Microalgae from Canary Islands for Functional Food and Feed Uses.
- Author
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Santiago-Díaz P, Rico M, Rivero A, and Santana-Casiano M
- Subjects
- Antioxidants chemistry, Aspartic Acid metabolism, Butylated Hydroxytoluene, Carbohydrates, Food Additives metabolism, Functional Food, Glutamates metabolism, Proline metabolism, Spain, Water metabolism, Microalgae chemistry
- Abstract
Three freshwater microalgae (Spirogyra sp., Cosmarium sp., and Cosmarium blytii) collected from several locations in Gran Canaria have been studied to explore their potential as a novel source of bioactive compounds for biotechnological applications. Soluble carbohydrates were quantified after extraction with 3 M HCl at 100 °C, ranging from 35.8 to 43.3 %, and with water at room temperature, ranging from 19 to 22.8 %. Amino acids glutamic acid, proline and aspartic acid were quantified by RP-HPLC. Glutamic acid was the most abundant, ranging from 12.2 to 3.63 mg g
-1 of dry biomass. Cosmarium blytii was the richest sample in amino acids (24.02 mg g-1 of dry weight). In addition, Cosmarium blytii and Spyrogira sp. exhibited higher radical scavenging activity (RSA) against 1,1-diphenyl-2-picrylhydrazyl (DPPH) than that of the synthetic antioxidant butylhydroxytoluene (BHT), commonly used as food additive. These results show a great potential of these microalgae for exploitation in the food, feed and pharmaceutical industries., (© 2022 The Authors. Chemistry & Biodiversity published by Wiley-VHCA AG, Zurich, Switzerland.)- Published
- 2022
- Full Text
- View/download PDF
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