1. Benthic Processes in Barkley Canyon and on the Adjacent Shelf Alex Hay and Doug Schillinger Dalhousie University NEPTUNE Canada Science Workshop Victoria 12-15 April 2010

2. Goal: Evolution of the mobile seabed through time due to biological and physical forcing mechanisms

4. Side View

5. Top View

6. Canyon Axis Depth 900 m (Pod 1) Pit

7. Canyon Wall Depth 700 m (Pod 3)

8. Shelf Depth 400 m (Pod 2) Pits Everywhere!!

9. Movies

10. Decorrelation Time still 30% correlated after 2 weeks, and levels off due to pit persistence

12. all 3 rotary sonars have been operating since Dec 2009 hourly images since 3 Feb 2010 routine processing is in hand and starting to look at time scales of change on the shelf, ~ 50 cm diameter pits persist for months during winter what is the formation mechanism? will they change as the seasons progress through spring/summer/fall? Summary

13. DMAS Needs a driver for rotary sonars to enable automated image acquisition at at least 2 ranges, and to speed up the rotation rate with the present setup, operating the sonars using the manufacturer’s software via a PC in Port Alberni, it takes 7 minutes to complete one 360-deg rotation, and we need several rotations to eliminate fish shadows from the images routine storage of raw rotary sonar data on the DMAS server

14. FIN

15. Summary: Problems CTD ground fault noise from switching power supplies (DC-DC converters) data from Delta-T multibeam sonar unusable Aquadopp current profilers could not be deployed