Marin overvåking Nordland 2013: Undersøkelser av hydrografi, bløtbunnsfauna og hardbunnsorganismer i 6 fjorder i Nordland

This report presents data from monitoring performed in 6 fjords (Glomfjorden, Nordfoldfjorden, Sagfjorden, Tysfjorden, Ofotfjorden og Øksfjorden) in Nordland in 2013. Hydrographic measurements were made and water samples were analyzed for nutrients, chlorophyll a, and oxygen at 12 stations. Soft-bottom in the sublittoral zone was sampled at 6 stations, and analyzed for faunal composition. Hard-bottom communities in the littoral zone were investigated at 19 stations. Various indexes have been used to calculate the status of the water quality conditions in the fjords. There is not yet sufficient data to classify the water quality based on the nutrient and chlorophyll a data collected. Results from the chlorophyll a measurements showed high concentration in Nordfoldfjorden in the second half of March due to start of the spring bloom in this fjord, but not in the other fjords. Mean values of nutrients were higher and secchi depths lower at the stations in Glomfjorden compared with the other fjords. The oxygen concentration in the bottom-waters was high at all stations. Lowest concentration were at the stations in Glomfjord, but due to lack of water samples no classification were done. All stations meet the criteria for very good conditions. Analysis of the soft-bottom fauna showed good to very good conditions at all of the investigated stations. The results corresponded with the oxygen measurements that showed high oxygen concentration in the bottom-waters. Analysis of the species composition in the macroalgae communities in the littoral zone showed good to very good conditions at all the investigated stations. The index used to calculate the environmental conditions based on macroalgae (RSLA index) is not yet approved for the fjords north of Glomfjorden. The results must therefore be regarded accordingly.