Some oceanographic features of northeastern Atlantic waters west of Ireland

Physical, chemical and biological observations were made in the oceanic and shelf waters of the northeast Atlantic to the west and northwest of Ireland in the spring and summer of 1990-1993. A predominant feature on the shelf to the west of Ireland was a thermohaline front separating Irish coastal water from oceanic waters further offshore. Over the shelf, temperature/salinity data showed a core of water freshening and cooling as it progressed northwards up the Rockall Channel. A consistent feature observed in spring was the existence of a wedge of warm, high salinity water flowing through the Porcupine Seabight onto the eastern side of the Porcupine Bank. In spring, surface dissolved oxygen and nutrient data were inversely related suggesting biological control of their distributions at this time of year. Small interannual variations were observed suggesting differences in the timing of the spring phytoplankton bloom between years. A brief description of the spring and summer phytoplankton biomass and species composition is presented.