Eutrophication of Lakes: From Global Process to Regional Implication in the Kola Arctic Region

Eutrophication of water bodies is analysed as a global process. The volumes of globally increasing use of nitrogen and phosphorus are demonstrated, with the dispersion of these elements leading to increased nutrient contents in lakes and rivers. Results of original studies on remote lakes in the Arctic zone indicate that the content of nutrients in these lakes has increased over the past decades. Concentrations of nitrogen, phosphorus and organic matter in lake waters tend to increase in the absence of anthropogenic effects. Simultaneously, the silicon concentrations were found to decrease because of the consumption by diatoms. Low concentrations of bioavailable nutrients confirm that these nutrients are rapidly spent in the production processes of ecosystems. The calculated trophic state index (according to R. Carlson) indicates that the number of oligotrophic lakes in the forest tundra zone decreased by 50% by 2010–2018, and these lakes are absent from the northern taiga zone. Temperature increase and climate warming in the Arctic zone first caused the increase in the contents of nutrients in the lakes and their trophic states.