Miljøundersøkelser i norske fjorder: Grenlandsfjordene 2000-2009

Abstract

The local input of antrohropogenic nutrients increased winter and summer values of nitrate and summer values of chlorophyll-a in the Grenland fjords. In the upper layer of the Frierfjord, the Brevikfjord and rhe Eidangerfjord the environmental conditions related to nitrate were” less good” and in the Håøyfjorden and the the Langesund bay (coast) ”good”. Summer average chlorophyll - a values in the upper layer of the Eidanger - and Brevikfjord were” less good” (3.6 -4.1 mg/m3) and in the Frierfjord and Håøyfjord ”good” (3 - 3.3 mg/m3). Both long distance and local supply of anthropogenic organic matter have reduced the oxygen concentrations in the Grenland fjordic basins. In Brevik and the Eidangerfjord, the average oxygen minimum was 3-3.5 ml/l (less good). In the Håøyfjord and Frierfjord, the oxygen conditions in the basins were “poor 5 to very poor” with average oxygen minimum values between 0 and 2.5 ml/l.