On 11-12 September, we laid a new extension cable from Folger node up into very shallow water on Folger Pinnacle, where an instrument platform will be installed by divers later this year. Poor visibility and strong swell made this installation particularly challenging.
The node is positioned in the main channel connecting Barkley Sound to Port Alberni Inlet. Water is quite turbid at the seafloor in this channel. We could barely make out the node from a distance of 2m, so ROPOS was sent down with a small video camera attached to one arm, which made it easier to see the connector ports in the murky water.
Murky Waters |
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ROPOS crew had a tough time finding and releasing the cable end connectors from the ROCLS cable drum, 12 September 2009.
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Even from 1m distance, the trawl-resistant frame was difficult to make out.
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This was the view when ROPOS reached the seafloor near our Folger Passage node, 12 September 2009.
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When we moved from the channel up onto the rocky terrain of Folger Pinnacle, strong surge became our enemy. ROPOS seemed powerless to hold position as the waves caused the sub to surge, sway and heave erratically. We had to maintain a safe distance and were unable to set ROPOS down to gather high-resolution images of proposed instrument platform site.
Rocky Terrain |
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This spectacular anemone was observed growing on rock at 41m.
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Close-up view of hard rock community observed at 30m 12 September 2009.
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White anemones colonize a boulder at 43m, 12 September 2009.
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Fish are numerous in the vicinity of Folger Pinnacle, which is a rock fish conservancy. This school was observed at 30m, 12 September 2009.
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Shell hash at the base of a rock outcrop at 30m depth.
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Rock fish swimming at 45m over rocky terrain in the mid-ground between the node and Folger Pinnacle, 12 September 2009.
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After laying the cable, the next task was to stabilize it. We prepared burlap bags filled with sand, planning to pin the cable down with them.
The sand bags were loaded onto the ROPOS tool tray, and ROPOS ferried the tool tray to the seafloor. However, when it reached the rocky bottom, a sudden swell drove ROPOS downward, smashing the tool tray onto the rocks. It snapped. With the heavy surge, it was too dangerous to reach many of the sand bags or attempt to recover the broken tool tray. The dive was aborted and we were forced to leave them on the seafloor.
Our chief scientist is now arranging for a crew of divers to swim to the cable and re-stabilize it before the winter storm season begins.
Sand Bag Travails |
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Some sandbags were placed to stabilize the cable before conditions became too dangerous to continue.
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A chimera visits the broken ROPOS tool tray resting on the rocky seafloor at 43m, 12 September 2009.
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Sand bags rest in the ROPOS tool tray prior to deployment, 12 September 2009.
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Folger Pinnacle Platform Location
We were able, however, to decide on a future location for Folger Pinnacle instrument platform. A relatively flat rock, 22m below the surface is the likely site. This fall, if all goes right, a custom platform will be fabricated and installed there.
Proposed Folger Pinnacle Instruments
- high-resolution video camera with lights
- current meter
- acoustic Doppler current profiler (1200 kHz)
- acoustic current profiler (2 MHz)
- ecosounder
- fluorometer
- 3-D high-resolution camera array
Learn more about research planned for this location.
Glimpses of Folger Pinnacle |
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Prospective site for the Folger Pinnacle platform.
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The shallow rocks of Folger Pinnacle provide habitat for a profusion of benthic organisms.
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Flourishing community of organisms living atop Folger Pinnacle, 12 September 2009.
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