Kartläggning av kväve i vatten i LKAB:s verksamhet i Malmberget år 2011 och kvävets betydelse i akvatiska ekosystem ur ett lokalt och ett globalt perspektiv

Sammanfattning: The nitrogen cycle is included in the biogeochemical cycles that connect all the organisms in one giant ecosystem, the biosphere. The nitrogen cycle is important both in a global perspective where the greenhouse gas N2O affects the climate and in a local perspective where it controls different processes in ecosystems. The availability of nutrients also have a great influence on all aquatic ecosystems because an increased availability often results in eutrofication that lead to negative effects on the ecosystems organisms. Nitrogen is especially important in aquatic ecosystems because it affects primary production which constitutes the base in foodwebs. Human activities have increased the flow of nutrients during the last century which has resulted in widespread eutrofication where the ecosystems have responded with hypoxia, loss of habitat and changes in food webs. To decrease the human influence on aquatic ecosystems measures must be taken. The Swedish authorities therefore put demands on companies like LKAB that runs a mining business in the northern part of the country. Because of these demands LKAB takes a lot of measures to decrease their impact on the environment. One of the measures is to find strategic methods for mapping of nitrogen in their business in Malmberget. In the future these methods can result in a decrease of LKAB’s influence on the surrounding ecosystems and enable a better follow-up of coming measures. Six samples for measuring nitrogen in the water that flows in their underground mine have been placed and one calculation of the amounts of nitrogen in their business has been done. The calculation revealed that the highest amount of nitrogen in the production water came from Anrikningsverket in the year of 2007. Measures done by LKAB is only one in several measures taken around the world and confined to a small geographical area but is still meaningful because all together, local measures results in a global effect.