Nutrient distributions in warm-core ring 82-B April–August

Abstract

The chemical, physical and biological distributions of a single warm-core ring, WCR 82-B, were examined in a multidisciplinary study of the ring from March to August 1982. WCR 82-B formed in late February 1982; in April the core water of the ring was isothermal and isohaline, with a homogeneous distribution of nutrients and oxygen from the surface to a depth of 350 m. Thermal stratification occured in early May; nutrients were depleted from the surface layer after stratification. In the core of the ring (radius < 20 km) nitrate lost from the surface layer after stratification was regenerated in the thermostad (a layer of isothermal and isohaline water extending from the base of the seasonal thermocline to the top of the main thermocline); silicate lost from the surface water was not regenerated in the thermostad, but was regenerated in the main thermocline. Between 2 July and 5 August the ring had a series of interactions with the Gulf Stream; the ring diameter was reduced from 110 to 70 km and the thickness of the 15–16°C thermostad was reduced from 350 to 200 m. Nutrient and oxygen distributions in the thermostad were not significantly changed by the Gulf Stream interactions.