April 8th, 2003; Leg 4, Day #5

Today's update is provided by Susan Von Thun.

Area of Study: Guaymas Basin

Site: Near Rebecca’s Roost

Today we returned to the sites we were at yesterday. We were in search of two small Riftia clumps. We wanted to get a good sample of the fauna associated with the tubeworms. This incredible little scale worm Branchiplicatus sp. (a.k.a. fuzzy foot) was found in one of yesterday’s samples and identified by Jean Marcus (see right). Our hope was to keep as much of the associated fauna in the clump as possible. This is not such an easy task. We must put the clump in a bucket in the ROV drawer, move the bucket and all of its contents to the benthic elevator, close the top of the elevator box, and release the elevator to the surface. A benthic elevator is a piece of equipment that scientists use to deploy and recover extra samples and equipment so they can collect more samples than if they just had space on the ROV. We successfully collected 2 very nice clumps of Riftia tubeworms and were able to get the buckets into the elevator. The ROV pilot in control of the manipulator was able to tip the bucket on its side and close the box. The elevator was released, quickly rising to the surface.   

In this image, the ROV pilot successfully 
placed a bucket of tubeworm samples 
into the benthic elevator.

The ship’s crew worked hard to recover the elevator quickly. The ship got as close as possible. Steven threw a line out to drag it closer to the ship (above left). Once they got the line up, they attached it to the crane, operated by Darrell Palmer (above center). Then they pulled it over to the stern. At right, Steven and Erik pull the elevator up onto the fan tail. 

Things can happen to samples on the way up to the surface and on this dive the elevator was damaged, resulting in the loss of one of our Riftia clumps. That’s not surprising considering the complexity of collecting deep-sea samples. 

Each day, based on new experiences during each dive, we are working with the ROV pilots and the ship’s crew to optimize our sample recovery. We like to call this adaptive sampling! Stay tuned for more of the good, the bad, and the ugly parts of deep sea exploration…

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