PULSE 53: Pelagic-Benthic Coupling and the Carbon Cycle
September 17 - September 23 , 2007

September 22, 2007

Mike Vardaro writes:
After lifting 16 heavy weights and attaching four of them to each leg of the FVGR, arming all four of the grabs by pulling on the spring-loaded jaws and holding them open while attaching the release cables to burn wires, arming the Niskin water-sampling bottles in similar fashion, charging batteries, connecting and programming the computer for a two-day incubation and sampling routine, shackling 7 separate racks of syntactic foam blocks together and attaching them to the top of the vehicle in order to give it enough buoyancy to come back to the surface... after all that, watching it rise on the winch and settle on the back deck with open, mud-less, failed grabs is a little dispiriting.

The good news is that we recorded the oxygen data from each grab. The bad news is that a computer error caused the grabs to think it was two days earlier than it was, meaning they didn't fire and close, didn't collect the mud they were holding and the bottles didn't collect any water samples. As it was too late in the cruise to reset it and deploy it again, we simply had to take the data that we DID get, and be sure that this particular error doesn't happen again. With a piece of equipment this complex, there are always things that can go wrong - the important thing is to learn from each deployment, and try to make it a better instrument for next time.

While we were downloading the data from the FVGR, we launched the ROV to go check on the Benthic Rover. It was still working correctly and doing its thing - rolling along, putting down chambers, taking measurements, picking up chambers and rolling farther along - so we left it and started some more ecological transects. Along the way we stopped to collect some sponge samples, tried to collect a sea anemone ("tried" because as the ROV's robotic arm extended a suction sampler towards it, the anemone curled in on itself into a tiny ball and floated away...), took some mud core samples to sift for macrofauna (small animals of a certain size range, able to be caught by a 300 micron sieve screen), and grabbed a giant predatory tunicate (a clear, gelatinous organism about half a meter high that sits on the mud and opens and closes its huge mouth, capturing animals that swim by like a deep-sea Venus Fly-trap).

Sunrise at Station M on Day 6 of the Pulse53 MBARI ExpeditionTomorrow should be more of the same, and then the cruise is over, so we have to collect everything we are after, retrieve all of our equipment and start packing up to steam back to Moss Landing! It will be nice to get back on land, but the weather has improved so much and things are running so smoothly at this point that it's a pleasure to be out at sea, away from the daily distractions and errands of normal land-lubber life. Here you can see the sunrise on day six while at Station M.

Ahoy from Station M,

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