KVÄVE ELLER FOSFOR – VAD ÄR BEGRÄNSANDE NÄRSALT I KUSTOMRÅDEN? EXEMPEL FRÅN NORSKA FJORDAR / Nitrogen or Phosphorus – what is Limiting Nutrient in Coastal Areas? Examples from Norwegian Fjords
The dominating role of phosphorus as limiting nutrient in fresh water is well documented, while the situation in coastal areas and the open sea is less clear. In the marine environment phosphorus (P) and nitrogen (N) availability appears to be more balanced to the nutrient requirements of algae. When nutrient limitation is discussed, it is necessary to distinguish between limitation of the algal growth rate and limitation of the biomass production in a system. It is the nutrient limitation of potential biomass production that should be of concern when measures against eutrophication are planned. The potential biomass production is determined by the availability of nutrients, which in turn depends on physical transport and biological transformations. Examples from Norwegian fjords show an increasing tendency of P-limitation with decreasing salinity which may be ascribed to the high N/P-ratio in land runoff. This motivates the use of phosphorus removal in wastewaters discharged into fjords influenced by fresh water. “Complete abstract not presented.”