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A test deployment of a time-lapse camera lander in the deep Oslofjord (431 m) was used to obtain initial information on the response of benthic fauna to macroalgal debris. Three macroalgal species were used on the lander baited plate: Fucus serratus, Saccharina latissima and Laminaria hyperborea and observed during 41.5 hours. The deep-water shrimp Pandalus borealis were attracted to the macroalgae rapidly (3 min after the lander reached the seafloor), followed by amphipods. Shrimp abundances were significantly higher in areas covered by macroalgae compared to the adjacent seafloor and the number of shrimp visiting the macroalgae increased with time. Amphipods arrived 13 hours later and were observed mainly on decaying L. hyperborea. The abundance of amphipods on L. hyperborea increased rapidly, reaching a peak at 31 h after deployment. These initial observations suggest that debris from kelp forests and other macroalgal beds may play an important role in fuelling deep benthic communities in the outer Oslofjord and, potentially, enhance secondary production of commercial species such as P. borealis.

A method used in to estimate uptake of hydrophobic pollutants in marine hard bottom organisms is described. Radio-labelled toxicants (14C-PCB77 and 14C-BaP) were used in a closed continuous-flow system without making use of solvents. Concentrations of PCB77 and BaP in the water were relatively high and stable during the experimental periods (14 days). The experimental set-up gave a satisfactory dispersion of the toxicants in the water and the use of radiochemicals made analyses quick and inexpensive. Algae (Fucus vesiculosus) and mussels (Mytilus edulis) were exposed to the toxicants and uptake was principally rapid and significant. Algae exposed to PCB77 reached a steady-state level within 24 h. No steady-state level was observed for BaP during exposure. Mussels showed an approximately linear uptake rate with no steady state observed for either of the toxicants. Organisms moved to a clean environment showed no reduction in PCB77 content. For BaP a slow depuration rate was observed. The rapid uptake of PCB and BaP by the organisms, and the accumulation and retention of the substances in the tissue for a long time, may result in a considerable pool of toxicants stored in these organisms.

Unintentional effects of the antifouling agent tributyltin (TBT) have been discovered in marine gastropods as the induction of male sex characters in females, known as imposex. The occurrence of imposex in dogwhelks (Nucella lapillus) was investigated in 41 populations sampled in 1993–1995 along the Norwegian coast. A method for quantification of organotin species using gas chromatography and atomic emission detection (GC-AED) was developed. Some degree of imposex occurred in almost all populations of dogwhelks studied, except in four from Northern Norway. The concentration of organotin compounds in the gastropods from the unaffected populations was below the detection limit (7 ng Sn/g d.w.). The concentration of TBT in dogwhelks from affected populations was in the range 48–1096 ng Sn/g d.w. A positive relation between the concentration of TBT in dogwhelks and the degree of imposex was found.