Tuesday, July 20, 2010

Picking up a Package

Over the last few years, researchers with Fisheries and Oceans Canada have been compiling physical oceanographic data on the water masses and current circulation around Orphan Knoll. In addition, data on abundance and diversity of pelagic zooplankton as well as the concentration of bacteria around and across the knoll has been collected during this time.

As part of this initiative, moorings with attached near bottom current meters were placed at strategic locations around the knoll (right inset). The Fisheries and Oceans Research team conducting this research on the Knoll made a trip here in May. In an effort to gather another 2 full months of current meter data, the DFO team left the moorings in place in hopes that they could be retrieved during our mission.
Tomorrow morning we will begin the first, and most challenging, of 3 mooring recoveries. Each of the moorings is equipped with a release that is triggered remotely by DFO staff from the ship (left). During the initial deployment, the signal for one mooring (highlighted in blue) was lost at ~1500 m water depth. It is unlikely that the equipment on the morning will be released remotely from the ship, thus ROPOS has been tasked to find and recover this mooring.

Upon reaching the mooring's last known location, ROPOS will turn on their long range sonar (100 m) in an effort to visualize the mooring at a distance well beyond the scope of their 2100 watt light bank. Once found, ROPOS will waypoint the location and then begin a 5 km grid transect to profile the ocean bottom near the current meter (right). At the end of the transect, ROPOS will return to the mooring location and bring it back to Hudson.

The dive will take approximately 15 hrs to complete including the search for the mooring.

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