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Norge er en av få nasjoner i verden som tillater undersjøisk deponering av avgangsmasser fra gruvedrift. Tidligere tiders filosofi basert på "ute av syne, ute av sinn" er imidlertid ikke et argument som fungerer i dagens samfunn. Det har derfor vært et sterkt fokus på kunnskapsinnhenting knyttet til hvordan slik deponering påvirker marint miljø de senere år.&nbsp

Recent large influxes of non‐native Pacific pink salmon (Oncorhynchus gorbuscha) to North European rivers have raised concern over their potential negative impacts on native salmonids and recipient ecosystems. The eggs and carcasses of semelparous pink salmon may provide a significant nutrient and energy subsidy to native biota, but this phenomenon has not been widely documented outside the species' native distribution. We analysed the stomach contents and stable isotope values (δ15N and δ13C) in muscle and liver tissues of juvenile Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) to determine whether these native salmonids utilise marine‐derived nutrients and energy provided by pink salmon eggs and carcasses in the subarctic river system Vesterelva, northern Norway. Although egg foraging and assimilation of marine‐derived nutrients in fish body tissues were found to be minor at the population level, a few juvenile salmon and trout had recently eaten large quantities of pink salmon eggs. Some of these individuals also had high δ15N and δ13C values, indicating a long‐term diet subsidised by marine‐derived nutrients and energy from pink salmon eggs. Hence, our study provides novel evidence that the eggs of invasive pink salmon may provide an energetic, profitable food resource for juvenile native fish. More research is needed to understand the broader ecological implications for fishes and other biota in river ecosystems invaded by pink salmon. peerReviewed

Recent large influxes of non-native Pacific pink salmon (Oncorhynchus gorbuscha) to North European rivers have raised concern over their potential negative impacts on native salmonids and recipient ecosystems. The eggs and carcasses of semelparous pink salmon may provide a significant nutrient and energy subsidy to native biota, but this phenomenon has not been widely documented outside the species' native distribution. We analysed the stomach contents and stable isotope values (δ15N and δ13C) in muscle and liver tissues of juvenile Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) to determine whether these native salmonids utilise marine-derived nutrients and energy provided by pink salmon eggs and carcasses in the subarctic river system Vesterelva, northern Norway. Although egg foraging and assimilation of marine-derived nutrients in fish body tissues were found to be minor at the population level, a few juvenile salmon and trout had recently eaten large quantities of pink salmon eggs. Some of these individuals also had high δ15N and δ13C values, indicating a long-term diet subsidised by marine-derived nutrients and energy from pink salmon eggs. Hence, our study provides novel evidence that the eggs of invasive pink salmon may provide an energetic, profitable food resource for juvenile native fish. More research is needed to understand the broader ecological implications for fishes and other biota in river ecosystems invaded by pink salmon. egg predation, marine-derived nutrients, non-native salmonids, resource subsidy, stable isotope analysis, subarctic river

This is the peer reviewed version of the following article: Ruus, A,, Øverjordet, I.B., Braaten, H.F.V., Evenset, A., Christensen, G.N., Heimstad, E.S., ... Borgå, K. (2015). Methylmercury biomagnification in an Arctic pelagic food web. Environmental Toxicology and Chemistry, 34(11), 2636-2643. https://doi.org/10.1002/etc.3143, which has been published in final form at https://doi.org/10.1002/etc.3143. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. Mercury (Hg) is a toxic element that enters the biosphere from natural and anthropogenic sources, and emitted gaseous Hg enters the Arctic from lower latitudes by long-range transport. In aquatic systems, anoxic conditions favor the bacterial transformation of inorganic Hg to methylmercury (MeHg), which has a greater potential for bioaccumulation than inorganic Hg and is the most toxic form of Hg. The main objective of the present study was to quantify the biomagnification of MeHg in a marine pelagic food web, comprising species of zooplankton, fish, and seabirds, from the Kongsfjorden system (Svalbard, Norway), by use of trophic magnification factors. As expected, tissue concentrations of MeHg increased with increasing trophic level in the food web, though at greater rates than observed in several earlier studies, especially at lower latitudes. There was strong correlation between MeHg and total Hg concentrations through the food web as a whole. The concentration of MeHg in kittiwake decreased from May to October, contributing to seasonal differences in trophic magnification factors. The ecology and physiology of the species comprising the food web in question may have a large influence on the magnitude of the biomagnification. A significant linear relationship was also observed between concentrations of selenium and total Hg in birds but not in zooplankton, suggesting the importance of selenium in Hg detoxification for individuals with high Hg concentrations. Environ Toxicol Chem 2015;34:2636–2643. © 2015 SETAC

Appendix 8/15 of the publication "State of the environment in the Norwegian, Finnish and Russian border area 2007" (The Finnish Environment 6/2007).

Appendix 5/15 of the publication "State of the environment in the Norwegian, Finnish and Russian border area 2007" (The Finnish Environment 6/2007).