Sediment Community Oxygen Consumption along a Shelf-slope Transect in the Western Gulf of Lions

Abstract

SCOC measurements were carried out on a seasonal basis during 1997 and 1998 along a transect from the shelf to the slope of the western Gulf of Lions (northwestern Mediterranean). Values ranged from 0.6 to 48.0 mmol O₂ m⁻² d⁻¹ and decreased with increasing depth. The overall mean was 11.2 ± 1.0 mmol O₂ m⁻² d⁻¹ for the shelf and 23 ± 1.9 mmol O₂ m⁻² d⁻¹ for the slope, with a significant difference between canyon axis (average 37 ± 2.1 mmol O₂ m⁻² d⁻¹) and open slope sites (average 1.2 ± 0.8 mmol O₂ m⁻² d⁻¹).The highest values were registered in all stations in late spring, when they were 1.5 to 4.2 times higher than in other seasons, except for the shelf deepest station, which showed a slight temporal variation. Temporal and spatial variations appeared to be related to the benthic biological activity and organic matter input Our data confirm previous findings from other authors in the Gulf of Lions and highlight the importance of organic matter mineralization in this area in the frame of the processes occurring at the sediment-water interface.