Today (Dec. 3) we have again a calm morning with quiet seas. Perfect for a driving lesson and a newbie inauguration! The pilot-in-training is Jeff McDonald, the trainer is David Walter, and they take newbie Kai Ziervogel along for the ride. Kai is as calm and composed as possible under the circumstances, and poses here with Bruce for additional coolness.
They have a big program: Recover three T-loggers plus cores around them for UNC and MARUM; get the INSINC up (remember, the radioactive crockpot at the bottom); hunt for three hot and oily long cores, a number of Beggiatoa pushcores for shorebased collaborators, and a big slurpgunned fish for Javier (Comment: still missing Friday morning! We need that fish.). On the way up, they will collect a series of Niskin bottle water samples for chemical profiling of the water column, especially (you guessed it) oxygen.
Here you see the T-logger arrangement at the M27 mat, quite a beauty with well-demarcated orange and white Beggiatoa and brown sediments. By now we know that the T-loggers actually work; Howard has extracted the continuous temperature record of two weeks from the T-loggers at M14, and they look great. This makes the combined T-logger data and core sample sets something quite special. Note for the next time around: The T-logger handles poke out of the sediment a little, but it is obvious that this spot is not so easy to find. Next time we will need screaming, big markers attached to the T-loggers.
There is also the matter of the INSINC recovery. The radioactive tracer incubation has been sitting embedded in a nice white Beggiatoa mat on the seafloor for two days, Tuesday to Thursday (today), and has integrated over time the amount of seawater sulfate respired to sulfide, by sulfate-reducing bacteria. Now it is time to pick it up. We hope that sulfate has not run out! This will be an interesting comparison to the first in-situ incubation nearby.
Oxygen, T-logger cores and INSINC aside, the most urgent question on everyone’s mind is: Will they return safely? We assuage these fears by posting an official return picture. Yes, Kai is back in one piece, with the traditional post-dive expression on his face – the flush of scientific excitement mixed with the sheer joy of seeing the sun again.
Since this dive team is also returning the second set of radiotracer-injected INSINC cores, the swipe testing, core washing, and Alvin rinsing & hosing protocol is applied again. The radiotracer contamination swat team, Gunter and Hans, pose in the glowing sunset and make it plain that not a single cpm will make it beyond those guys undetected.