Dynamic of macronutrients and physical characterization from San Jorge Gulf (Patagonia, Argentina) during spring and summer

WILLIAMS, GABRIELA NOEMÍ; ESTEVES, JOSÉ LUIS; TORRES, AMÉRICO IADRAN; RIVAS, ANDRÉS LUJÁN; PAPARAZZO, FLAVIO E.; SOLÍS, MIRIAM

OCEANOGRAPHY

OCEANOGRAPHY SOC

Lugar: Rockville; Año: 2018 vol. 31

1042-8275

Following designation of San Jorge Gulf (SJG) as a priority for marineconservation by the Argentine scientific community, it was included in the ?PampaAzul? government initiative. As a contribution to this initiative, we analyzed macronutrientdistribution and its relationship to the stratification and primary producerbiomass in the water column during austral summer 2014 and spring 2016. In addition,we determined dissolved oxygen, chlorophyll concentrations, and pH. Duringboth seasons in the central and northern gulf, strong stratification separated nutrient-poor, oxygenated surface waters from nutrient-rich, less-oxygenated deep waters.Thermal stratification was correlated to nutrient concentrations. Oxygen decreased upto 60% in bottom waters, although hypoxic conditions were not found. Nitrate limitedprimary production in surface waters. A tidal front near the gulf ?s mouth in thesouth and wind-forced upwelling in the southwestern coastal zone naturally fertilizedthe waters. Although there is no information on the precise amount of nutrientseach source contributes to the SJG, a shortcut in the path toward resource conservationcould be directed through the processes associated with water column stratificationbecause it determines the availability of surface nutrients to primary producers.