Thursday, September 20, 2012

DAY THREE (9/19/12)

More excitement today!  Based on the detailed map from the previous day’s work, we spent the entire day exploring Baker Bank with the ROV.  After a deployment to balance the ROV’s buoyancy, the ROV followed two planned transects for video capture and then collected some samples.  We captured several hours of video, including almost three hours on the first transect and an hour on the second transect.  The transects began on opposite sides (landward and seaward) at the base of the bank and went up to the peak (shallowest depth). 
3D map of Baker Bank with overlay of ship's route while collecting multibeam data.
Image credit:  Harriet Nash; Schmidt Ocean Institute
Crew deploys ROV over Baker Bank.
Image credit: Mark Schrope; Deep Sea Systems International; Schmidt Ocean Institute
In a region known for murky waters filled with suspended mud and silt, scientists were thrilled to have good visibility at 70 meters below the sea surface.  The live video feed revealed a thriving ecological community with high biodiversity at Baker Bank.  Scientists identified several species of sponges ranging in color from white to purple; fields of coiled wire corals; sea fans; black corals; sea whips; crinoids; feather hydroids; branching coralline algae; sea cucumbers; brittle stars; oyster clams; and juvenile and adult reef fishes including butterfly fishes, angelfishes, wrasses, porgies, snappers, and damselfishes.  Unfortunately, videographers also identified a lionfish, which is an invasive species that feeds on native reef fish species.  Technicians used regular video, 3D video, and three different types of cameras to capture images and map sightings throughout the dive.  Scientists will use the imagery and data to describe the community and biodiversity of Baker Bank.
Pilot James Sherwood controls ROV from the ship's navigation room.
Image credit:  Mark Schrope; Deep Sea Systems International
Screen capture of video imaging showing wide-mesh sea fan.
Image credit: Harriet Nash; Deep Sea Systems International; Schmidt Ocean Institute

The ROV pilot attempted twice to collect push core samples of sediment, but the sediment was so fine and loose that it was not compacted enough to remain in the sampling tube.  However, the ROV’s robotic arm did successfully collect a few samples:  two sponges and a black coral sea fan. 
A specimen of black coral that was collected from Baker Bank.
Image credit: Harriet Nash
Microscopic image of the black coral specimen showing six tentacles around each polyp mouth.
Image credit: David Hicks; Schmidt Ocean Institute
Day 3 Sunset
Image credit: Maureen Trnka

After Drs. Shirley and Tunnell charted out the next day’s activities with the captain and technology crew, several scientists gathered in the library to end a long day by watching “The Neverending Story,” the book and movie after which the R/V Falkor and its safety boats were named.
Written by Harriet Nash for HRI at TAMUCC.

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