Changes in Mediterranean and Atlantic Ocean currents
The MORIA project, led by the UB, will study the impact of Mediterranean waters on the North Atlantic circulation weakened by climate change
image: The MORIA project, led by the UB, will analyse how Mediterranean outflow water masses are affected by the Atlantic meridional overturning circulation, an ocean current that is becoming slower and weaker due to global warming and is key in global climate regulation
Credit: UNIVERSITY OF BARCELONA
The Atlantic meridional overturning circulation (AMOC) is a major oceanic current determining global climate that is showing signs of weakening. It transports warmer waters northwards in the Atlantic Ocean, sinks colder and denser waters and is a climate regulator in the northern European continent. According to some hypotheses and computer models, the impact of climate change and melting of the poles could eventually collapse the AMOC, with effects on global ocean regulation and climate that are difficult to predict. In this complex system of ocean currents, how do these affect the water masses flowing from the Mediterranean into the Atlantic along the course of the AMOC?
The objectives of the oceanographic campaign of the MORIA project (Mediterranean outflow reach and impact into the North Atlantic: present and past variability using neodymium isotopes), led by the University of Barcelona, will focus on studying the circulation of Mediterranean outflow water (MOW) and its impact on the Atlantic Ocean current. MORIA will be the first national campaign included in the international GEOTRACES project, focused on the study of marine biogeochemical cycles of trace elements and their isotopes. This recognition is an endorsement of international scientific quality of the highest level in oceanography.
The MORIA project is led by researchers Leopoldo Pena and Isabel Cacho, with the outstanding participation of experts Jaime Frigola and Galderic Lastras, all members of the Marine Geosciences Research Group (Gmar) at the UB’s Faculty of Earth Sciences.
Other institutions involved in the project and the campaign are: the Institute of Marine Sciences (ICM-CSIC), the Spanish Institute of Oceanography in Vigo (IEO-CSIC), the University of Las Palmas de Gran Canaria and the Institute of Marine Research (IIM-CSIC). The French Research Institute for Exploitation of the Sea (IFREMER), ETH Zurich (Switzerland), the University College Cork (Ireland) and Aarhus University (Denmark) are also active partners.
Oceanographic campaing from the coast of Vigo to Reykjavik
From 15 September to 11 October, the MORIA campaign will sail from the coast of Vigo to Reykjavik, aboard the oceanographic ship Sarmiento de Gamboa (CSIC), in a journey that will follow the circulation of Mediterranean waters along the European Atlantic margin. The oceanographic campaign will characterize the Mediterranean waters as they move northwards and study the possible impact of changes in the MOW on the AMOC.
“There is growing evidence that the AMOC is a highly sensitive system that could collapse in the future, with unpredictable climatic consequences,” says Professor Leopoldo Pena, from the UB’s Department of Earth and Ocean Dynamics.
Water masses leaving the Mediterranean Sea — warmer, denser and saltier — move from the Strait of Gibraltar to the Atlantic Ocean, and follow the margin of the Iberian Peninsula and the European continent in the direction of higher latitudes. “This powerful current of water from the Mediterranean transports large quantities of salt, mixes with the surrounding water from higher latitudes and increases its density, which makes the AMOC system work more efficiently,” notes Professor Jaime Frigola.
Changes in Mediterranean and Atlantic Ocean currents
The team plans to obtain about 800 samples of Mediterranean water — at various locations and depths — for detailed characterization with various geochemical tracers, such as neodymium (Nd) isotopes and other rare earths. The equipment of Laboratory of Radiogenic and Environmental Isotopes (LIRA), at the Faculty of Earth Sciences, will be instrumental in analysing and reconstructing the chemical properties of the samples obtained and quantifying the amount of Mediterranean water masses exported to more northerly latitudes.
MORIA will also study key parameters in the carbon cycle, such as alkalinity, pH, nutrients, oxygen content, salinity and dissolved metal content (Fe, Cu). In parallel, the experts will also work with sediment samples from the ocean floor to analyse, with different indicators, sequences of the sedimentary record to study the variability of the MOW in the more recent past.
The MORIA project (2023-2027) is part of Strategic Action 5 — Climate, energy and mobility — of the State Plan for Scientific, Technical and Innovation Research 2021-2023, an initiative that promotes research into the impacts of climate change. It was requested within the framework of the 2022 call for Knowledge Generation Projects of the Ministry of Science and Innovation.
The MORIA project and the oceanographic campaign directly benefit from the results of TRANSMOW, an earlier project that focused on a similar characterization of the Mediterranean outflow from the Strait of Gibraltar to Gijón, on the western margin of the Iberian Peninsula.