REDISTRIBUTION OF THE EPIBENTHIC, SOFT-BOTTOM ASSEMBLAGE IN SHIFTING HYPOXIC CONDITIONS
We repeated a 2 km benthic transect (annually for 7 years) across a shifting oxycline (<0.05 to > 3 ml/l) to determine epibenthic response to spatially shifting levels of hypoxia. ROVs with high-definition cameras and a CTD/O2 transected from 180 to about 50 m in Saanich Inlet, a highly productive fjord with seasonally occurring severe hypoxia on the west coast of Canada. Species-specific tolerance of hypoxia determined their spatial distribution which shifted with the changing horizontal oxygen profile. Multivariate analyses determined that the maximum, not mean, oxygen level best predicts the presence of the animal assemblage. Slender sole and squat lobsters dominate the community living on bacterial mats in severe hypoxia (O2 < 0.5 ml/l). As oxygen levels increase (O2 > 0.75 ml/l), more species appear including commercial species of fish and crustaceans. The high resolution time-series from the nearby VENUS observatory (96 m depth) shows a trend of oxygen loss in the past 7 years. As hypoxic waters encroach into the shallows, the area inhabitated by commercial species will likely be compressed and interactions among species increased.
Chu, J., University of Victoria, Canada, email@example.com
Tunnicliffe, V., University of Victoria, Canada, firstname.lastname@example.org
Time: 16:00 - 18:00
Location: Poster/Exhibit Hall
Presentation is given by student: Yes