The atmospheric carbon dioxide (CO₂) levels have been on the rise since the preindustrial era because of the exponentially increasing anthropogenic activity. The ocean has absorbed about 30% of the anthropogenic CO₂, lessening its impact on the climate, but generating “the other CO₂ problem” which refers to ocean acidification.

Oceanic acidification surveillance is a special duty for UN Agenda 2030 (SDGs 13.2 and 14.3). They state the needing of observe on global scales in order to understand ocean acidification (OA) and its drivers correctly with the goal of knowing the global status of OA and its implications and have sufficient data to develop predictive skills and early warning systems. In response to that, CSIC have created the interdisciplinary thematic platform (PTI) WATER:iOS (Warming and Acidification Threats on Ecosystem Resources: iOcean Surveillance), bringing together people, skills and expertise from several institutions to contribute to ocean acidification surveillance.

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.

Out of the total dissolved inorganic carbon (DIC) in the ocean, the anthropogenic fraction represents 3% of it at maximum. In spite of its apparently modest contribution, this amount suffices to cause severe impact on the oceanic acidity (30% of ion hydrogen increase) and heat content. The fact that anthropogenic CO₂ uptake represents such a small fraction of DIC 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 pH determinations, gas-extraction total inorganic carbon (TIC, DIC) determination and total alkalinity measurement through potentiometric titration.

Nitrous oxide (N₂O) and methane (CH₄) are biologically produced trace gases that exerts a strong climate influence as powerful greenhouse gases which also affect stratospheric ozone depletion (N₂O) and the oxidative capacity of the atmosphere (CH₄). Because the ocean emits one third of the global N₂O natural emissions to the atmosphere, the observations has been targeted mainly toward low oxygen oceanic regions, limited in extension but characterised by intense N₂O production. However, the capacity to uptake N₂O and its injection into the deep ocean circulation in ventilated regions such as the North Atlantic Ocean and the subpolar gyre have received until now little attention. This knowledge is urgently needed to refine our estimations of the global oceanic N₂O budgets.

The main research interests of the CO₂ Group at the Vigo Marine Research Institute focus on the following:

• Study of Ocean Acidification trends and their drivers in the Open Ocean, coastal systems and national parks.
• Improvement of the analytical and methodological techniques in anthropogenic CO₂/N₂O estimation.
• Technological developments for surveillance acidification in coastal systems.
• Contribution to international evaluation of the global and regional CO₂/N₂O/CH₄ cycle assessment and processes.
• Development of numerical techniques with neural networks for the study of ocean and coastal acidification.
• Development of automatic laboratory systems for the observation of the response of marine species to future scenarios.
• Biogeochemical modeling.
• Providing value-added services for customers on CO₂/N₂O/CH₄ surveillance:
  • AQUANITROMET service.
  • PEACHESEA service.

• REDEIRA
• AtlAZUL
• BOCATS2
• ARIOS
• AtlantOS
• BOCATS
• MYTIGA
• CATARINA
• CARBOCHANGE
• CARBOOCEAN
• OVIDE
• M4AO
• DIPLOMACIA
• ECO V.O.S.
• CAIBEX

• CRITERIA

• Fiz Fernández Pérez (Dr.) - Profesor de Investigación - Sistema del CO2 - Masas de agua - Cambio climático
• Miguel Gil Coto (Dr.) - Científico Titular - Oceanografía Física
• Xosé Antonio Padín Álvarez (Dr.) Titulado Superior de Actividades Téc. y Prof. - Personal Laboral fijo
• María López-Acosta (Dr.) Post Doc en LEMAR-IUEM (Brest)
• Antón Velo Lanchas (Dr.) Titulado Superior de Actividades Téc. y Prof. - Personal Laboral fijo - Acidificación - Control de calidad de datos
• Mercedes de la Paz Arándiga (Dra.) Contrato Titulado Superior
• Daniel Broullón Durán Contratado predoctoral para la Formación de Profesorado Universitario
• Marta López Mozos Contratada predoctoral para la Formación de Personal de Investigación
• María Jesús Álvarez Fernández Titulado Superior de Actividades Téc. y Prof.
• Jesús Rey Muras Ayudante de Investigación de OPIs

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

• φ-CT0 CANT estimation method Matlab scripts
• φ-CT0 CANT1994 gridded to WOA 1 degree / 33 levels grid
• Atlantic 1994 Carbon Inventory, gridded to WOA 1 degree / 33 levels grid
• Atlantic 2004 Carbon Inventory, gridded to WOA 1 degree / 33 levels grid
• Atlantic Decadal (1994-2004) Carbon Change per Year, gridded to WOA 1 degree / 33 levels grid