BUSCADOR RECOLECTA

PUMP Cruise (29HE20140831) carried out on the Research Vessel Hespérides in 2014, Study of the Vertical Oceanic Pump in mesoscale eddies (PUMP). This project will study the dynamics/kinematics of the ageostrophic secondary circulation (ASC) and mixing in surface mesoscale anticyclonic eddies and how they modulate plankton activity, plankton community structure, and accumulation and downward transport of organic matter (the Vertical Oceanic Pump, VOP). For this purpose we will conduct a novel interdisciplinary sampling strategy to survey an anticyclonic eddy from a Lagrangian perspective with a resolution down to the submesoscale range using cutting-edge instrumentation and methodologies. We will pay particular attention to the control of the ASC by eddy/wind interaction, by mixing, and by current/wind interaction and frontogenesis/frontolysis at its periphery. ASC will be diagnosed from trajectories of drifters drogued at the Ekman layer and at the eddy´s interior and using an omega-type equation that will include direct measurements of mixing/turbulence. Mixing regime, dynamic stability and vertical diffusion of tracers will be observed and derived from direct measurement of mixing/turbulence. Near-inertial waves trapping and its role in driving shear mixing will be studied from drifter trajectories and from the vertical variability of the horizontal velocity field. To establish the dynamics that forces the VOP we will also develop processes-oriented models and implement regional physical and physical-biogeochemical models for the Canary Region. We will also take advantage of the exceptional source of tracer provided by the El Hierro Island submarine volcanic eruption for the study of eddy submesoscale spatial-temporal variability, combining satellite images and modeling. Finally the physical and biogeochemical observations and processes will be combined and correlated to derive a conceptual model of the dynamics of the marine system linked to the VOP in mesoscale eddies

HOTMIX Cruise (29SG20140427) carried out on the Research Vessel Sarmiento de Gamboa in 2014, This project will study the influence of mixing zones between water masses on the metabolism and biodiversity of microbial communities, and their impact on biogeochemical fluxes, in the deep ocean. The project will be carried out in the Mediterranean Sea as an example of experimental laboratory for its dynamic characteristics, with turnover times an order of magnitude smaller than in the open ocean (11 to 100 years). We will follow the evolution of the Levantine Intermediate Water (LIW) from its generation, in the eastern basin of the Mediterranean Sea until its flow to the North Atlantic through the Strait of Gibraltar. During its westward flow the LIW mixes both with surface water of Atlantic origin and deep Mediterranean waters, formed both in the eastern (Adriatic and Aegean Seas) and western (Gulf of Lions) basins. After outflowing through the Gulf of Cadiz, the LIW sinks down and spills over into the eastern Atlantic Ocean, mixing with different Atlantic waters, like the North Atlantic Central Water (NACW), the Subpolar Modal Water (SPMW) and the Labrador Sea Water (LSW). We will reproduce the "in situ" conditions (temperature, pH and hydrostatic pressure) in the deep ocean to study microbial metabolism using advanced methodologies. We will also examine the relationship between diversity, microbial metabolism and the elemental and molecular composition of the available organic matter at these interface regions. Finally, we will compare estimates of metabolic rates with geochemical approaches based on multiparametric analysis of water masses (OMP) and age estimates from transient tracers, helping to resolve the paradox of the imbalance between sources and sinks of carbon in the deep ocean