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Title: The Distribution Of Phytoplankton And Nutrients In The North East Irish Sea During 1996;
Author: K Kennington
Author: J R Allen
Author: T M Shammon
Author: R G Hartnoll
Author: A Wither
Author: Environment Agency
Author: P Jones
Document Type: Monograph
Annotation: Environment Agency Project ID:EAPRJOUT_354, Representation ID: 88, Object ID: 1698
Objectives of this research have been to monitor the distribution and concentrations of nutrient and phytoplankton abundances in the north-eastern Irish Sea. Specific aims have been to identify areas potentially at risk from the adverse effects of excessive nutrient discharges from sewage and industrial outfalls. Although any such exercise is constrained by the infrequent sampling dates, certain conclusions can be made, albeit tentatively. The industrial discharges from Albright & Wilson (Whitehaven) and BNFL (Sellafield) are readily apparent in the data presented. Soluble reactive phosphorus (SRP) concentrations have been recorded at elevated concentrations around Whitehaven during 1995 (Allen et al. 1996) and 1996 (herein). Nitrogenous compounds have also been recorded above background coastal concentrations along the coastal margin adjacent to Sellafield for these time periods. At present these waters exceed the guidelines of the Comprehensive Studies Task Team (with regard to winter observations of DAIN and DAIP) for High Natural Dispersion Areas. Some concern must also be registered with reference to concentrations of summer surface chlorophyll concentrations which exceeded the 10 ~kg/1 threshold (outlined by the CSTD during May. The relatively high chlorophyll concentrations reported adjacent to Sellafield for May were reflected in increased phytoplon counts. A comparison between winter nutrients and summer phytoplankton suggests that winter TON and silicate may best explain the phytoplankton community structure. Discharges of orthophosphate from Albright & Wilson are expected to decrease over the next few years, however discharges of nitrogenous and phosphorus concentrations from BNFL are likely to increase as throughput increases and new operations commence in 1998/99. This again raises some cause for concern, and may result in some adjustment of the N:Si ratios which are already indicating that waters extending from the Solway Firth to the Ravenglass estuary may be prone to future eutrophication. Such reductions in N:Si may actively alter the phytoplankton community structure favouring non-siliceous organisms with the possibility of increased occurrences of nuisance algae. The discharge of nutrients into Liverpool Bay stems mainly from the rivers Mersey, Ribble and Dee. On all sampling occasions from the present study nutrients were recorded to be of greatest concentrations around the Mersey and Dee estuaries. Nutrient concentrations exceeded the criteria outlined by the CSTT at almost all locations within the Liverpool Bay during the winter sampling period and must cast doubt upon the provisional classification of this region as a 'Less Sensitive Area. The winter N:Si ratio suggests that these waters are prone to eutrophication. Although no evidence of nuisance algae has been reported from the current study, Liverpool Bay has been prone to blooms of Phaeocystis pouchetii in recent years. The high abundances of Dinophysis sp. reported for 1996 also warrant further investigation into the spring/summer phytoplankton community as species of this genus are a known threat to public health and fisheries alike.
Publisher: Environment Agency
Subject Keywords: Coastal watersEstuariesNutrientsPhytoplanktonWater pollutionWater qualitySurveysAlgal bloomsPhosphorus
Extent: 90
Total file downloads: 304

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