Monitoring of outer Oslofjord 2014-2018. Benthos Surveys in 2015. Technical report

Summary

Benthic investigations in Outer Oslo fjord included in 2015 surveys of soft bottom fauna at 10 stations by grabbing, with three replicate samples at each station. Most of the stations in the Hvaler estuary and open part of the Outer Oslo fjord could be classified to be in “good condition” (condition class 2). The exception was one station (D-2) near the island Kjøkøy in the Hvaler estuary which could be classified to be in "moderate condition”. The Iddefjord was clearly organic polluted and the sediments showed relatively high concentrations of total organic carbon (TOC) and odor of H2S. Based on the makrofauna date two stations in the Iddefjord/Ringdalsfjord (ID-1 and ID-43) could be classified to be in "poor condition, while station R-5 a bit further out could be classified to be in "good condition."