| Summary: | Mussel production in the Galician Rías, which reaches 250000 tons per year and represents 95% of Spanish production and 50% of European production, is based on the high productivity of phytoplankton favored by the upwelling of nutrient-rich subsurface waters. The phytoplankton blooms take place when the conditions of light and nutrients availability are favorable. This availability is conditioned by the degree of turbulent mixing of the water column that determines the vertical movement of the cells and, therefore, their exposure to the light that penetrates from the surface. In addition, turbulent mixing takes part in the diffusion of nutrients from deep water to shallower layers, where they can be assimilated by phytoplankton. The classic Sverdrup model predicts that the North Atlantic spring bloom takes place when the mixed layer becomes shallower at the end of winter, allowing greater phytoplankton exposure to sunlight. Given the methodological impossibility of characterizing the mixing conditions at that time, the Sverdrup model assumes that the turbulence in the mixed layer is high enough to uniformize, on a short time scale, the properties within it. The technological development at the last decades has allowed to characterize the intensity of turbulent mixing in situ. The main objectives of this doctoral thesis are: (1) to characterize the turbulence at seasonal scale in the Ría de Vigo and determining the mechanish the mechanisms that generate it; (2) to study the relationship between the seasonal variability of the turbulent mixing and the phytoplankton growth; and (3) to study the role of turbulent mixing in the availability of light and nutrients in the phytoplankton growth. La producción de mejillón en las Rías Gallegas, que alcanza 250000 toneladas anuales y representa el 95 % de la producción española y el 50 % de la europea, se sustenta en la elevada productividad del fitoplancton favorecida por el afloramiento de aguas subsuperficiales ricas en nutrientes. Las proliferaciones de fitoplancton ...
|
|---|