A seasonal study of the distribution of surface state variables in Liverpool Bay. v. summer

Physical, chemical, and phytoplankton distributions observed in the surface waters of Liverpool Bay in summer 1977, are reported and compared with those recorded earlier during the seasonal development cycle. The observations coincided with the presence of an extensive bloom of Phaeocystis pouchetii (Harriot) Langerheim. A lateral density discontinuity through the Bay continued to provide a sharp line of demarcation between the characteristics of the offshore and coastal waters while highest phytoplankton cell numbers, dominated by Phaeocystis, occurred along the length of the discontinuity. Data on sub-surface distributions are also presented and show that at this time of year heterogeneities in the water characteristics of this area are compounded by spatial variabilities in the propensity of the coastal waters to stratification. Where the coastal waters were stratified warm, less saline surface waters characterized by low phytoplankton numbers and low species dominance overlay cooler, more saline waters exhibiting high phytoplankton densities dominated by Phaeocystis. The decrease in the vertical stability of the water column at the offshore discontinuity allowed the high cell numbers residing in the bottom coastal waters to be dispersed towards the surface.