Phytoplankton and nutrient dynamics in the north-east Irish Sea

Results are presented for a suite of surveys investigating the distribution of phytoplankton and nutrient salts in the northeast Irish Sea during 1996 . The ratio of one nutrient salt to another was calculated and it was noted that winter N:P ratios were greatest in less saline inshore waters. Elevat ed levels of both N and P were observed to be associated with regions of in dustrial and riverine inputs. Phytoplankton community data is linked to env ironmental variables via a multivariate statistical analysis. Results of th is analysis suggest that winter TON and silicate concentrations may best ex plain variations in the spring phytoplankton community structure. A bloom o f the prymnesiophyte Phaeocystis pouchetii was recorded in waters in the no rth of the study area and which appears to be associated with nutrient poor waters.