BOTTNARNA I ÅSFJORDEN, VÄNERN, KARAKTERISERADE MED BILDANALYS / Benthic habitat quality assessment of Åsfjorden, Lake Vänern, by sediment profile imaging

In September 1997, the benthic habitat in Åsfjorden in Lake Vänern was studied at 23 stations by sediment profile imaging. Grab samples for qualitative analysis of the fauna was taken at nine stations. The sediment surface was oxidized at all stations and showed indication of biological activity by rubificids and chironomids in the entire Åsfprden. The deepest infaunal acdvity and distribudon ofthe sub-oxic layer in the sediment were recorded in the central and southern parts ofthe Åsfjorden, which suggests that the bottom quality was best here. The use of sediment profile imaging, which has been frequently used in marine areas, gave rapid information of the benthic habitat quality also in this freshwater environment.