EFFECTS OF NITRATE AND PHOSPHATE DISCHARGE FROM A FERTILIZER PRODUCTION PLANT IN A FJORD

Pedersen, A.^1,2, Knutzen, J.², Walday, M.², Molvær, M.² & Johnsen, T.^{2 1}Department of Ecology and Evolutionary Biology, University of Connecticut at Stamford, Stamford, CT. 06901 U.S.A;. ²Norwegian Institute for Water Research, P.O.B. 173 Kjelsås, 0411 Oslo, Norway. “Hydro Agri Glomfjord” a fertilizer producer has been discharging large quantities of ammonium, nitrate and phosphate into Glomfjord (in northern Norway, N 66,48°, E 13,57°) since 1947. The effects of the nutrient load to the Fjord have resulted in classical eutrophication symptoms. Elevated nutrient levels have resulted in frequent plankton blooms and seasonally reduced O₂ levels in the deep-water bodies as well as an eradication of the normal littoral assemblages. The fucoid belt had been replaced by various green algae 6 km from the outlet and outward the fjord. The effect is only seen on the northern side of the Fjord. After some improvement in the discharge loads in the 1980's, the condition in the pelagic column improved with regard to plankton blooms and deep water O₂ concentration. The littoral communities didn't, show any indication of recovery and a pollution indication index based on algal composition, showed even increased eutrophication.