Monday, March 2, 2015

We're having a Mega-good time!

As far as deep sea sediment collection goes, it doesn’t get much better than the Mega-corer! 

Multiple corers are known for collecting the most pristine, undisturbed samples from the depths, and our Mega-corer is no exception. With its complicated mechanics, this lady can be very temperamental, but with the proper love and attention it has proven very reliable for bringing back high quality samples on each dive.

The clear "top water" visible above the mud in the tubes, is an indicator that the samples are pristine because the sediment would have muddied the water had the surface sediments been disturbed upon collection.

Cassie Turner typically maintains the mega-corer between dives, and checks every nut, bolt, spring, and moving part each time it comes back on board. It is cleaned, tuned, and lubricated each time it comes on deck to ensure that it brings back 12 cores each time it is sent into the abyss.

Amanda Ziegler carries the heavy pinger out on deck.

A Pinger is placed on the winch wire 50 meters above the Megacorer to track it's descent to the bottom.

<Thomas Dahlgren holds the pinger while it is secured to the winch wire. He has a perfect record of not dropping a single one!! {knock on wood}
Each tube is photographed before it is removed for processing. Here Colin Seifer holds the label plate>

Upon recovery, special hooks are used to attach tag lines to the corer that will stabilize it while it is brought onto deck. Here Thomas Dahlgren prepares to attach a tagline while Helena Wiklund waits to remove the pole from the loading area. The ship's experienced crew, also pictured, are always very helpful in ensuring seamless deployments and recoveries.

  Amanda Ziegler is ready with wood planks, which are placed under the Mega-corer upon recovery. Having it set on the planks makes it easier to remove the sample tubes without losing top water or risking disturbing the sample.

The samples that we get from the mega-corer are divided among four teams of scientists and analyzed for macrofauna, meiofauna, genetics, and bioturbation among other analyses. 

When the megacorer comes on deck, all the scientists gather around to examine the cores and make their picks. It feels like a football draft as each team of scientists takes turns picking their preferred cores.

During some of the deployments, we have had some trouble with the shackle that attaches the Mega-corer to the winch wire allowing the wire to loop and fowl on the top of the corer. This causes some tense moments upon recovery because it usually ends in the Mega-corer slipping loose and dropping a few feet, risking the loss of
 samples or even the whole Mega-corer!    

To solve this problem, Craig Smith, the Chief Scientist, devised a rubber boot that covers the shackle and prevents it from fowling on the Mega-corer. The maiden voyage of the boot was last night, and it appeared to work perfectly! We were pleased to see the Mega-corer return to deck un-tangled and with 12 cores in toe.

Written by: Cassandra Turner, University of Hawaii at Manoa

1 comment:

  1. Great to read this blog. Awesome to see the "ghetto-rigged" boot replacing the piece of buoyant rope usually used with OSIL corers...nice touch. Sounds like you're having loads of mud fun. Keep up the good work! Cheers, Jeroen