Sammendrag
The aim of the surveys is to monitor and state the ecological environment in 6 different fjords in Nordland county where there is an active aquaculture industry. The marine surveillance program was designed according to the requirements of the previous classification guide (01: 2009), but from 2015 the criteria in the latest guide (02: 2013) have been followed, as is the classification. In the period 2017-2018 investigations were conducted in Nordfoldfjorden, Sagfjorden, Tysfjorden, Ofotfjorden, Øksfjorden and Sjona. They included the two biological quality elements phytoplankton (chlorophyll a) and macroalgae (hard-bottom communities in the littoral zone) and supporting parameters for these. The report covers the period from July 2017 through June 2018 and gives a simple presentation of the results. However, final classification of all quality elements and monitoring years will be presented in a final report in 2019.
For the biological quality element phytoplankton (chlorophyll a), the results for 2017-2018 show a more intense bloom for some stations compared with previous years, particularly for the stations in Sjona. The time series of chlorophyll a data, 2013 to 2018, clearly shows a yearly spring bloom in March-April. In 2017 there was an additional bloom in the period May-June. For the nutrient ammonium (NH4) there were higher concentrations during the summer months in 2017 compared with previous years, especially for the stations in Sjona. This applies in part to Tysfjorden as well, but later in the year. For nitrate (NO3), high concentrations appeared in the winter months when water stratification is weak, while they fall to low levels after the spring bloom period. Station SJON2 in Sjona stands out by having high nitrate concentrations compared to the other fjords and previous years.
As the present report only presents hydrographic observations and data for nutrient and chlorophyll a, there has not been given a final classification of the biological quality element phytoplankton. The results from the tentative classification from last year's report, however showed "Very good" ecological status for the stations in Nordfoldfjorden, Tysfjorden, Sagfjorden, Øksfjorden and Ofotfjorden, of which one station in Ofotfjorden (OFOT2) was classified as "Good". Since Sjona first was introduced in the monitoring program in 2016, the stations in this fjord do not yet satisfy the requirements for classifying the ecological state for phytoplankton.
The results from the oxygen measurements in deep bottom-water show that all stations have good conditions. There are small changes in oxygen concentrations in the fjords compared with the 2016 results and all stations have "Very good" status, except SJON2 which has "Good" status.
Analysis of the species composition in the macroalgae communities in the littoral zone showed “Good” to “Very good” conditions at all 18 investigated stations. A total of 60 macroalgae species/taxa and 26 fauna species/taxa were registered in the survey. Note that the index used to calculate the environmental conditions based on macroalgae (RSLA/RSL index) is not yet approved for the fjords north of Sjona (the other five fjords in this survey) and the results must therefore be regarded accordingly.
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