Observations on the surface water characteristics in the western Irish Sea: July 1977

Distributions of physical, chemical and biological characteristics observed in the frontal region of the western Irish Sea during July 1977 are presented. High chlorophyll concentrations and phytoplankton cell numbers were associated with the lateral thermal discontinuity. The characteristics of the stratified and mixed waters varied along the length of the front, such that the changes recorded across each frontal transect were unique. The qualitative composition of the diatom population on either side of the front, however, was distinctive. Observations, concentrated on one transect, showed that the diatom population at the front was a mixture of the populations on either side, and that the high phytoplankton standing crop there was predominantly stimulated by nutrient complementation.