CO2IIM :: CO2 en el océano

Research Background & Fields of Interest

The atmospheric carbon dioxide (CO2) levels have been on the rise since the Pre- Industrial era as a result of the exponentially increasing anthropogenic activity. Amongst all human activities, the main industrial CO2-emitting practices are the combustion of fossil fuels, cement production and land-use changes (massive logging, extensive farming and forestry of fast-growth species).

Every year the atmosphere receives 7 Gt (Gt = gigatons = thousands of millions of tons) of carbon derived directly from such human activities (anthropogenic carbon or Cant). Approximately 50% of these atmospheric CO2 emissions remain on the air, while the other half is captured and stored in the oceanic and land biosphere environmental compartments.

The ocean naturally behaves as a CO2 sink by uptaking up to 2 Gt of anthropogenic CO2 per year. Within this scenario, the North Atlantic is one of the grandest CO2 sinks in the global ocean as major water mass formation processes favour the sequestration of CO2 either through mixing or dissolving.

The CO2 uptake capacity of the ocean varies largely depending on the water mass ventilation rhythms. If we aim to ever understand and evaluate the CO2 storage capacity of the present day and future oceans, then a state of the art knowledge and acquaintance of the water mass mixing and formation rates is mandatory through continuous monitoring and evaluation. The main research interests of the CO2 Group at the Vigo Marine Research Institute focus on the following:

  1. Study of the air-sea CO2 exchange fluxes variability.
  2. Improvement of the analytical and methodological techniques in anthropogenic CO2 estimation.
  3. Water mass CO2 transport and mixing processes.

Out of the total dissolved inorganic carbon (TIC) in the ocean, the anthropogenic fraction represents 3% of it at max. In spite of its apparently modest contribution, this amount suffices to cause severe impact on the oceanic acidity, general circulation patterns and heat content. The fact that Cant represents such a small fraction of TIC is also one of the major handicaps when it comes to its determination. The CO2 group is continuously assessing and improving the accuracy of the analytical procedures used to measure the seawater carbon system. At present, the following techniques are being applied: spectrophotometric and potentiometric pH determinations, coulometric TIC determination and total alkalinity measurement through titration/potentiometry. To top it off, autonomous equipments have also been developed to perform on-board underway measurements of CO2 partial pressure during oceanographic cruise





  • Carracedo L.I.; M. Gilcoto; H. Mercier; F.F. Pérez. Seasonal dynamics in the Azores-Gibraltar Strait region : A climatologically-based study. Progress in Oceanography. 122, pp. 116 - 130. 2014.
  • Pardo P.C ; F.F. Pérez; S. Khatiwala; A.F. Ríos. Anthropogenic CO2 estimates in the Southern Ocean: Storage partitioning in the different water masses. Progress in Oceanography. 120, pp. 230 - 242. 2014
  • Zunino, P., Garcia-Ibañez, M. I., Lherminier, P., Mercier, H., Rios, A. F., and Pérez, F. F.: Variability of the transport of anthropogenic CO2 at the Greenland–Portugal OVIDE section: controlling mechanisms, Biogeosciences, 11, 2375-2389, doi:10.5194/bg-11-2375-2014, 2014.
  • Bakker, D. C. E., Pfeil, B., Smith, K., Hankin, S., Olsen, A., Alin, S. R., Cosca, C., Harasawa, S., Kozyr, A., Nojiri, Y., O'Brien, K. M., Schuster, U., Telszewski, M., Tilbrook, B., Wada, C., Akl, J., Barbero, L., Bates, N. R., Boutin, J., Bozec, Y., Cai, W.-J., Castle, R. D., Chavez, F. P., Chen, L., Chierici, M., Currie, K., de Baar, H. J. W., Evans, W., Feely, R. A., Fransson, A., Gao, Z., Hales, B., Hardman-Mountford, N. J., Hoppema, M., Huang, W.-J., Hunt, C. W., Huss, B., Ichikawa, T., Johannessen, T., Jones, E. M., Jones, S. D., Jutterström, S., Kitidis, V., Körtzinger, A., Landschützer, P., Lauvset, S. K., Lefèvre, N., Manke, A. B., Mathis, J. T., Merlivat, L., Metzl, N., Murata, A., Newberger, T., Omar, A. M., Ono, T., Park, G.-H., Paterson, K., Pierrot, D., Ríos, A. F., Sabine, C. L., Saito, S., Salisbury, J., Sarma, V. V. S. S., Schlitzer, R., Sieger, R., Skjelvan, I., Steinhoff, T., Sullivan, K. F., Sun, H., Sutton, A. J., Suzuki, T., Sweeney, C., Takahashi, T., Tjiputra, J., Tsurushima, N., van Heuven, S. M. A. C., Vandemark, D., Vlahos, P., Wallace, D. W. R., Wanninkhof, R., and Watson, A. J.:An update to the Surface Ocean CO<sub>2</sub> Atlas (SOCAT version 2), Earth Syst. Sci. Data, 6, 69-90, doi:10.5194/essd-6-69-2014, 2014.|


  • Cobo-Viveros, A.M., Antonio Padin, X., Otero, P., De la Paz, M., Ruiz-Villarreal, M., Ríos, A.F., Pérez, F.F., 2013. Short-term variability of surface carbon dioxide and sea-air CO<sub>2</sub> fluxes in the shelf waters of the Galician coastal upwelling system. Scientia Marina 77, S1, 37–48. doi: 10.3989/scimar.03733.27C
  • Pérez, F.F., Mercier, H., Vázquez-Rodríguez, M., Lherminier, P., Velo, A., Pardo, P.C., Rosón, G., Ríos, A.F., 2013. Atlantic Ocean CO2 uptake reduced by weakening of the meridional overturning circulation. Nature Geoscience. doi: 10.1038/ngeo1680
  • Velo, A., Pérez, F.F., Tanhua, T., Gilcoto, M., Ríos, A.F., Key, R.M., 2013. Total alkalinity estimation using MLR and neural network techniques. Journal of Marine Systems 111–112, 0, 11–18. doi: 10.1016/j.jmarsys.2012.09.002
  • Álvarez-Salgado X.A., M. Nieto-Cid, M. Álvarez, F.F. Pérez, P. Morin, and H. Mercier. New insights on the mineralization of dissolved organic matter in central, intermediate, and deep water masses of the northeast North Atlantic. Limnology and Oceanography. 58, pp. 681 - 696. 2013.
  • Jiang, Z.P., Hydes, D.J., Tyrrell, T., Hartman, S.E., Hartman, M.C., Dumousseaud, C., Padin, X.A., Skjelvan, I., González-Pola, C., 2013. Key controls on the seasonal and interannual variations of the carbonate system and air-sea CO2 flux in the Northeast Atlantic (Bay of Biscay). Journal of Geophysical Research: Oceans n/a–n/a. doi: 10.1002/jgrc.20087
  • Otero P., X.A. Padin, M. Ruiz-Villareal, L.M. García-García, A. F. Ríos, and F.F. Pérez. Net sea-air CO2 flux uncertainties in the Bay of Biscay based on the choice of wind speed products and gas transfer parameterizations. Biogeosciences. 10, pp. 2993 – 3005. 2013.
  • Schuster, U., McKinley, G.A., Bates, N., Chevallier, F., Doney, S.C., Fay, A.R., González-Dávila, M., Gruber, N., Jones, S., Krijnen, J., Landschützer, P., Lefèvre, N., Manizza, M., Mathis, J., Metzl, N., Olsen, A., Ríos, A.F., Rödenbeck, C., Santana-Casiano, J.M., Takahashi, T., Wanninkhof, R., Watson, A.J., 2013. An assessment of the Atlantic and Arctic sea–air CO2 fluxes, 1990–2009. Biogeosciences 10, 1, 607–627. doi: 10.5194/bg-10-607-2013
  • Racapé, V., Pierre, C., Metzl, N., Lo Monaco, C., Reverdin, G., Olsen, A., Morin, P., Vázquez-Rodríguez, M., Ríos, A.F., Pérez, F.F., Anthropogenic carbon changes in the Irminger Basin (1981–2006): Coupling δ13CDIC and DIC observations. Journal of Marine Systems. doi: 10.1016/j.jmarsys.2012.12.005, In revision
  • Pfeil, B., Olsen, A., Bakker, D. C. E., Hankin, S., Koyuk, H., Kozyr, A., Malczyk, J., Manke, A., Metzl, N., Sabine, C. L., Akl, J., Alin, S. R., Bates, N., Bellerby, R. G. J., Borges, A., Boutin, J., Brown, P. J., Cai, W.-J., Chavez, F. P., Chen, A., Cosca, C., Fassbender, A. J., Feely, R. A., González-Dávila, M., Goyet, C., Hales, B., Hardman-Mountford, N., Heinze, C., Hood, M., Hoppema, M., Hunt, C. W., Hydes, D., Ishii, M., Johannessen, T., Jones, S. D., Key, R. M., Körtzinger, A., Landschützer, P., Lauvset, S. K., Lefèvre, N., Lenton, A., Lourantou, A., Merlivat, L., Midorikawa, T., Mintrop, L., Miyazaki, C., Murata, A., Nakadate, A., Nakano, Y., Nakaoka, S., Nojiri, Y., Omar, A. M., Padin, X. A., Park, G.-H., Paterson, K., Perez, F. F., Pierrot, D., Poisson, A., Ríos, A. F., Santana-Casiano, J. M., Salisbury, J., Sarma, V. V. S. S., Schlitzer, R., Schneider, B., Schuster, U., Sieger, R., Skjelvan, I., Steinhoff, T., Suzuki, T., Takahashi, T., Tedesco, K., Telszewski, M., Thomas, H., Tilbrook, B., Tjiputra, J., Vandemark, D., Veness, T., Wanninkhof, R., Watson, A. J., Weiss, R., Wong, C. S., and Yoshikawa-Inoue, H.: A uniform, quality controlled Surface Ocean CO<sub>2</sub> Atlas (SOCAT), Earth Syst. Sci. Data, 5, 125-143, doi:10.5194/essd-5-125-2013, 2013.
  • Sabine, C. L., Hankin, S., Koyuk, H., Bakker, D. C. E., Pfeil, B., Olsen, A., Metzl, N., Kozyr, A., Fassbender, A., Manke, A., Malczyk, J., Akl, J., Alin, S. R., Bellerby, R. G. J., Borges, A., Boutin, J., Brown, P. J., Cai, W.-J., Chavez, F. P., Chen, A., Cosca, C., Feely, R. A., González-Dávila, M., Goyet, C., Hardman-Mountford, N., Heinze, C., Hoppema, M., Hunt, C. W., Hydes, D., Ishii, M., Johannessen, T., Key, R. M., Körtzinger, A., Landschützer, P., Lauvset, S. K., Lefèvre, N., Lenton, A., Lourantou, A., Merlivat, L., Midorikawa, T., Mintrop, L., Miyazaki, C., Murata, A., Nakadate, A., Nakano, Y., Nakaoka, S., Nojiri, Y., Omar, A. M., Padin, X. A., Park, G.-H., Paterson, K., Perez, F. F., Pierrot, D., Poisson, A., Ríos, A. F., Salisbury, J., Santana-Casiano, J. M., Sarma, V. V. S. S., Schlitzer, R., Schneider, B., Schuster, U., Sieger, R., Skjelvan, I., Steinhoff, T., Suzuki, T., Takahashi, T., Tedesco, K., Telszewski, M., Thomas, H., Tilbrook, B., Vandemark, D., Veness, T., Watson, A. J., Weiss, R., Wong, C. S., and Yoshikawa-Inoue, H.: Surface Ocean CO<sub>2</sub> Atlas (SOCAT) gridded data products, Earth Syst. Sci. Data, 5, 145-153, doi:10.5194/essd-5-145-2013, 2013.








  • Castro CG, Nieto–Cid M, Álvarez–Salgado XA, Pérez FF. 2006. Local mineralization patterns in the mesopelagic zone of the Eastern North Atlantic of the NW Iberian Peninsula. Deep Sea Research I, 53:1925–1940.
  • Duarte, C.M., Alonso, S., Benito, G., Dachs, J., Montes, C., Pardo, M., Ríos, A.F., Simó, R., Valladares, F. 2006. Cambio Global. Impacto de la actividad humana sobre el sistema tierra. Colección Divulgación (ISBN: 978-84-00-08452-3). Editorial Consejo Superior de Investigaciones Científicas, Volumen 1: 1-166.


  • Álvarez, M., F.F. Pérez, D.R. Shoosmith and H.L. Bryden. 2005. The unaccounted role of Mediterranean Water in the draw-down of anthropogenic carbon. Journal of Geophysical Research 110: 1-18. doi: 10.1029/2004JC002633.
  • Pérez F.F., C.G. Castro, A.F. Ríos and F. Fraga. 2005. Chemical properties of the deep winter mixed layer in the Northeast Atlantic (40–47ºN). Journal Marine Systems 54: 115–125.
  • Ríos, A.F., F.F. Pérez, M. Álvarez, L. Mintrop, M. González–Dávila, J.M. Santana Casiano, N. Lefèvre and A.J. Watson. 2005. Seasonal sea–surface carbon dioxide in Azores area. Marine Chemistry 96: 35–51.


  • Álvarez M., F.F. Pérez, H. Bryden, A. F. Ríos. 2004. Physical and biogeochemical transport structure in the North Atlantic subpolar gyre. Journal of Geophysical Research 109, C03027 doi: 1 0.1029/2003JC002015.
  • Brea S., X.A. Álvarez-Salgado, M. Álvarez, F.F. Pérez, L. Mémery, H. Mercier, M.J. Messias. 2004. Nutrient mineralization rates and ratios in the Eastern South Atlantic. Journal of Geophysical Research 109, doi: 10.1029/2003JC002051.
  • Lefèvre N., A.J. Watson, A. Olsen, A.F. Ríos, F.F. Pérez T. Johannessen. 2004. A decrease in the sink for atmospheric CO2 in the North Atlantic. Geophysical Research Letters 31, doi: 10.1029/2003GL018957.
  • Sabine C.L., Feely R.A., Gruber N., Key R.M., Lee K., Bullister J.L., Wanninkhof R., Wong C.S., Wallace D.W.R., Tilbrook B., Millero F.J., Peng T.-H., Kozyr A., Ono T., Ríos A.F. 2004. The oceanic sink for anthropogenic CO2. Science 305, 367-371.


  • Álvarez, M, A.F. Ríos, F.F. Pérez, G. Rosón and H.L. Bryden. 2003. Transports and budgets of total inorganic carbon In the subpolar and temperate North Atlantic. Global Biogeochemical Cycles 17(1), 1002–1029.
  • Alvarez–Salgado, X.A., F.G. Figueiras, F.F. Pérez, S. Groom, E. Nogueira, A. Borges, L. Chou, C.G. Castro, G. Moncoiffe, A.F. Ríos, A.E.J. Miller, M. Frankignoulle, G. Savidge, R. Wollast. 2003. The Portugal Coastal Counter Current off NW Spain: new insights on its biogeochemical variability. Progress in Oceanography, 56, 281–321.
  • Gago J., X.A. Alvarez–Salgado, F.F. Pérez, and A.F. Ríos. 2003. Partitioning of physical and biogeochemical contributions to the short–time–scale variability of surface seawater pCO2 in a costal upwelling system: a novel quantitative approach. Marine Ecology Progress Series, 255, 43–54.
  • Pérez, F.F, M. Gilcoto and A.F. Ríos. 2003. Large and mesoscale variability of the water masses and the DCM the Azores Front. Journal Geophysical Research, 108 C7, 3215.
  • Ríos, A.F., Álvarez-Salgado, X.A., Pérez, F.F., Bingler, L.S., Arístegui, J., Mémery, L., 2003. Carbon dioxide along WOCE line A14: Water masses characterization and anthropogenic entry. J. Geophys. Res. 108, 3123, DOI: 10.1029/2000JC000366.
  • Rosón. G. A.F. Ríos, A. Lavín, F.F. Pérez, and H.K. Bryden. 2003. Carbon distributrion and fluxes in the subtropical North Atlantic Ocean (24.5ºN) . Journal Geophysical Research, 108 C5,3144–3158.


  • Álvarez, M., A.F. Ríos, G. Rosón. 2002. Spatio–temporal variability of air–sea carbon dioxide and oxygen fluxes in the Bransfield and Gerlache Straits during austral summer 95–96. Deep–Sea Research II 49, 643–662.
  • Álvarez, M., H.K. Bryden, F.F. Pérez, A.F. Ríos, G. Rosón. 2002. Physical and biogeochemical fluxes and net budgets in the subpolar and temperate north Atlantic. Journal of Marine Research 60, 191–262.
  • Pérez, F.F., M. Álvarez, A.F. Ríos. 2002. Improvements on the back–calculation technique for estimating anthropogenic CO2. Deep–Sea Research I 49, 859–875.


  • Pardo, C.P., M. Gilcoto, F.F. Pérez. 2001.Short–time scale coupling between termohaline and meteorological forcing in the Ría de Pontevedra. Scientia Marina 65 (suppl.1.), 229–240.
  • Pérez F.F., C.G. Castro, X.A. Álvarez–Salgado, A.F. Ríos. 2001. Coupling between the Iberian basin–scale circulation and the Portugal boundary current system. A chemical study. Deep–Sea Research I 48, 1519–1533.
  • Pérez F.F., J. Gago, M. Álvarez, A.F. Ríos. 2001. Temporal variability of atmospheric CO2 of the Spanish Atlantic Coast. Oceanologica Acta 24, 11–18.
  • Pérez, F.F., L. Mintrop, O. Llinás, M. Glez–Dávila, C.G. Castro, M. Álvarez, A. Körtzinger, M. Santana–Casiano, M.J. Rueda, A.F. Ríos. 2001. Mixing analysis of nutrients, oxygen and inorganic carbon in the Canary Islands region. Journal of Marine Systems 28, 183–201.
  • Ríos, A.F., F.F. Pérez, F. Fraga. 2001. Long–term (1977–1997) measurements of carbon dioxide in the Eastern North Atlantic: evaluation of anthropogenic input. Deep–Sea Research II 48, 2227–2239.


  • Castro C.G., F.F. Pérez, X. A. Álvarez–Salgado, F. Fraga, 2000. Coupling between the thermohaline, chemical and biological fields during two contrasting upwelling events off the NW Iberian Peninsula (Galician Coast). Continental Shelf Research 20, 189–210.
  • Mémery, L., M. Arhan, X.A. Álvarez–Salgado, M.–J. Messias, H. Mercier, G.C. Castro, A.F. Ríos, 2000. The water masses along the western boundary of the south and equatorial Atlantic. Progress in Oceanography 47, 69–98.
  • Mintrop L., F.F. Pérez, M. González–Davila, J. M. Santana–Casiano, A. Körtzinger, 2000. Alkalinity determination by potentiometry – intercalibration using three different methods. Ciencia Marina 26, 23–27.
  • Pérez, F.F., X.A. Álvarez–Salgado, G. Rosón, 2000. Stoichiometry of net ecosystem metabolism in coastal inlet affected by upwelling. The Ría de Arousa (NW Spain). Marine Chemistry 69, 217–236.
  • Pérez, F.F., A.F. Ríos, T. Rellán, M. Alvarez, 2000. Improvements in potentiometric seawater alkalinity determination. Ciencia Marina 26, 463–478.
  • Pérez, F.F., R.T. Pollard, J.R. Read, V. Valencia, J,.M. Cabanas, A.F. Ríos, 2000. Climatological coupling of the termohaline decadal change in Central Water of the Eastern North Atlantic. Scientia Marina, 64, 347–353.

Doctoral Theses

Ocean acidification along the 24.5°N section in the subtropical North Atlantic

Elisa Fernandez Guallart

Universidad de las Palmas de Gran Canaria. Febrero 2016.

Acidification and transports of water masses and CO2 in the North Atlantic

Maribel García Ibáñez

Facultad de Ciencias del Mar - Universidade de Vigo, 2015.

CO2 flux variability in the Galician and Californian upwelling systems

Alba Marina Cobo-Viveros

Facultad de Ciencias del Mar - Universidade de Vigo, 2015.

Optimización de métodos numéricos en la determinación de la acidificación en los océanos

Antón Velo Lanchas

Facultad de Ciencias del Mar - Universidade de Vigo, 2014

Subtropical North-East Atlantic water masses and transports

Lidia Carracedo Segade

Facultad de Ciencias del Mar - Universidade de Vigo, 2013

El CO2 antrópico en el Océano Austral

Paula Conde Pardo

Facultad de Ciencias del Mar - Universidade de Vigo, 2013

Temporal changes in natural and anthropogenic CO2 in the North Atlantic Ocean

Noelia Maria Fajar González

Universidade de Santiago de Compostela, 2013

CO2 antropogénico en el Atlántico

Marcos Vázquez Rodríguez

Facultad de Ciencias del Mar - Universidade de Vigo, 2009

Variabilidad de la presión de CO2 superficial en el Atlántico Norte

Xosé Antonio Padín

Facultad de Ciencias del Mar - Universidade de Vigo, 2009

Ciclo de la materia orgánica disuelta en un sistema de afloramiento costero

Mar Nieto Cid

Facultad de Ciencias del Mar - Universidade de Vigo, 2005.

Patrones de variabildad termohalina en la Ría de Vigo

Miguel Gil Coto

Facultad de Ciencias del Mar - Universidade de Vigo, 2004.

Descripción dinámica de la circulación en dos Rías Baixas: Vigo y Pontevedra

Belén Martín Míguez

Facultad de Ciencias del Mar - Universidade de Vigo, 2003.

Water masses and transports of physical and chemical properties in the Subpolar North Atlantic Gyre

Marta Alvarez Rodríguez

Facultad de Ciencias del Mar - Universidade de Vigo, 2002.

Transformaciones biogeoquímicas y flujos de carbono en la Ría de Vigo. Estudio de la variación estacional y de corta escala

Jesus Gago Piñeiro

Facultad de Ciencias del Mar - Universidade de Vigo, 2000.

Predicción numérica y contraste experimental de la circulación en la Ría de Vigo

Carlos Alberto Souto Torres

Facultad de Ciencias del Mar - Universidade de Vigo, 2000.

Current Projects


In-Memoriam Aída Fernández Ríos (Dra.) - Profesor de Investigación - Sistema del CO2 - Masas de agua - Estequiometría

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