Saturday, April 25, 2015

Kilo Moana: A big surprise.

Jason is in the water!
Our first dive began with much excitement of seeing the deep-sea vents at Kilo Moana. Our pre-dive work involved getting our samplers cleaned and placed on Jason. Since this was a late dive, the work had to be done in the dark which is not the easiest thing to do. The microbiologists needed to clean and disinfect their samplers, while the chemists needed to prepare their gas-tight water samplers (IGTs) for installing onto Jason or the elevator.
Nick, Gilbert, and Karen prep Jason for the first dive with help from Scott (left). Gilbert washes out a biobox (right)
Jeff, Morgan, Sean, and Vivian get ready to launch the elevator under Brett's supervision.

Jason being launched for the first dive
Routinely, the elevator is filled with samplers that can then be exchanged with their used counterparts on Jason during the dive. The elevator can then be raised to the surface and we can get our samples without needing to bring Jason to the surface. This allows Jason to continue working on the sea floor enabling us to work for days without stopping.

Once on the bottom, some 2600m below the ship, we returned to sites we visited in 2005 and 2009, where there had been active deep-sea hydrothermal vents.  
Elevator going in the water
Our first site yielded: extinct sulfide structures, lots of mussels, many dead mussels, occasional crabs (see below)... and as we proceeded in hope for some active deep-sea vents, our hopes diminished. The entire area was no longer active; snuffed out between 2009 and now. There are many possible explanations for this. Most likely the heat source that fueled the hydrothermal vents at Kilo Moana just waned and finally shut off.
Extinct chimney structure
Brisingid asteroid covering a hydrothermal marker
Hydrothermal mussels and Galatheid crabs still remain on the vent chimneys

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