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

September 23, 2007

Mike Vardaro writes:
Plate SpongeWell, the last day of the PULSE 53 expedition has come and gone, and all things considered we had an extremely successful cruise. The Benthic Rover (which was recovered first thing this morning) performed admirably, completing its program and collecting useable scientific data for the first time with its oxygen sensors. The long-term mooring was recovered and redeployed without incident, and the camera and sediment traps both worked and recorded 3 months of pictures and detritus samples to work through. The FVGR deployment was a success, since we collected the respiration data and made up for the unfortunate lack of mud samples with some ROV push cores.swimming cucumber holothuroidea

Today's ROV dive yielded more push cores from the enrichment experiment, which were sectioned, sieved and preserved for Markus Moeseneder (from Aberdeen) to examine later how the labeled algae was incorporated into the biomass of the sediment and the effects of the enriched samples versus the un-enriched control samples. After a couple of transects, we also collected some very interesting polychaete and Nemertian worms, a sea anemone (this one didn't get away, despite a valiant attempt to dive out of the biobox!), a fringed crinoid, some plate sponges and a few sea cucumbers. The polychaete was even alive and swimming when we took it out of the biobox, remarkable when you consider that it survived the extreme pressure and temperature changes during an ascent from 4000 meters deep.

All of the samples were preserved in ethanol for later genetic and anatomical tests, and then we began packing all of our (substantial) equipment so that we'd be ready to demobilize as soon as we hit the dock. Hopefully I won't get "dock rock" too badly - that's the feeling that everything is still moving back and forth even though you're on dry land. Sort of the opposite of seasickness, but still an unpleasant sensation. It usually doesn't last too long, and the work of unloading the ship will distract me from it. Anyway, this cruise has given us much data to work through, many fun memories of our time at Station M, and Jim Birch even made a (frequently hilarious) mini-documentary of it for everyone to share. Hope you enjoyed the daily messages from the MBARI science crew and that they conveyed at least some of the excitement that we feel every time we go to sea!

Cheers, Mike

enrichment of sediment

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