The Eastern North Atlantic Subtropical Gyre (ENASG) is a key component of the North Atlantic Ocean system, influencing meridional heat transport and biogeochemical cycles. ENASG comprises the Canary Current, flowing south along the African shelf-break and interacting with the Canary Upwelling at interannual, seasonal, and meso-timescales. The upwelling influences ENASG biogeochemistry by supplying nutrients and increasing phytoplankton productivity. However, in the Era of Global Change, sea surface warming, increased stratification, and weakened vertical mixing may decrease nutrient fluxes and productivity. There is also an increasing trend in extreme events such as marine heat waves, with potentially high impacts on marine ecosystems. These changes also affect the carbon biogeochemical cycle, which, in turn, interacts with trophic dynamics.
The nearly 30 years of data from the European Station for Time-series in the Ocean, Canary Islands (ESTOC) confirm the importance of these variabilities at multiple scales and of long-term trends, not only in the upper ocean but also at intermediate depths, where Antarctic Intermediate Water and Mediterranean Water interplay. Nevertheless, we are still far from a complete understanding of ENASG functioning due to its spatial heterogeneity, the diversity of water masses, and the number of relevant complex interaction processes taking place across scales. Zooplankton and micronekton contribute to the biological carbon pump through vertical diel migration, transferring carbon to deeper layers.
The subtropical and subpolar North Atlantic serves as a major CO2 sink, but uncertainties remain regarding CO2 flux variability influenced by physical, air-sea, and biological interactions. This project aims to explore ENASG and its manifestation in ocean dynamics, water mass characteristics, zooplankton and micronekton biomass, and CO2 fluxes. Additionally, we intend to characterize the distribution of microplastics in the area and their variability.
To achieve this, a multidisciplinary, multiplatform oceanographic campaign will be carried out to complement existing observations and the long-term ESTOC time series, allowing for the identification of space-time variability patterns in biogeochemical variables and microplastic distribution, from diurnal and submesoscale to interannual and long-term trends. This will help identify the role of physical drivers and advance a holistic understanding of ENASG as a complex marine ecosystem and its role in the global carbon cycle and climate change mitigation.
