Saturday, September 2, 2017

The main event

Friends, my day has finally come! I’ve been waiting for an ROV dive to recover the long-term deep-sea settlement experiment so I could begin my analysis, and I’m happy to announce the frame has been recovered! It is now safely on board, and oh, how cool are the samples!

It all started yesterday around dinner time. We were at the central Hausgarten station and the weather was cooperating, so we went for it and sent down the ROV. Got to be honest, I was expecting the dive to take a lot longer than it did. It was a tricky operation but went very smoothly. The ROV had to first dive to the seafloor and find the experiment, then the ship lowered a weighted cable with a spool of line on the end, which the ROV had to find, grab onto, unspool, bring to the experiment without getting tangled, and hook onto the top of the frame. Imagine putting a hook in an eye underwater without getting tangled up. Lots of things can go wrong.

Thankfully, the ROV team already had experience with the maneuver, so when I spoke to one of the pilots that morning, she insisted everything would be fine. And it was – the pilot got the hook on the frame on the first try. The ROV then got out of the way, and the ship’s winch raised the experiment 2500 m to the surface.

I spent most of the ROV dive in the control van, leaning as far forward out of my chair as I could without falling, scribbling notes to myself about what I was seeing on the plates. There were visible organisms – not very large, but definitely there. I could identify three different species right off the bat. The largest, most conspicuous individual was a sponge living not on the experiment but on the radar reflector, situated high on a staff above the frame itself. I made a mental note to collect the sponge from the radar reflector later and wrote its name in my notebook: Cladorhiza gelida.

When the experimental frame reached the surface, Melanie and I were standing ready. We had waterproof suits for ourselves, cable cutters to remove the plates, two giant bins of cold water to temporarily store them in, and forceps and jars to collect any other interesting animals on the frame. I took us a good three hours to get everything collected, stored, recorded, and set, but it was very satisfying to see my samples on board.

May the analysis begin! 

P.S. If you read German, I recommend this post about the experiment recovery on the official Polarstern blog. 

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