Wrapping Up and Returning to Surface
It is day nine and the aquanauts are wrapping things up. With the help of the surface based dive team scientific instruments, personal gear, and equipment are all being packed up, brought to the surface, and brought back to shore. Inside Aquarius things are being checked, stored, and cleaned up and another habitat technician has joined the crew below to oversee decompression.
The aquanauts will begin decompression at 4:00pm. They start the process in their bunks, lying quietly and going through three, twenty-minute cycles on oxygen with five minutes in between; this helps begin flushing of excess nitrogen from their tissues. The pressure inside the habitat will be reduced during this time at a rate equivalent to six minutes per foot of depth to about 30 feet. Then, over the next 16 hours while the aquanauts rest, keep hydrated, do a little movie watching, and get some sleep the pressure will continue to be reduced at a slower rate. Tomorrow morning the habitat will be at surface pressure, before being blown back down to about 50 feet so the aquanauts can make one last dive out through the moon pool where they will be met and escorted to the surface.
Even for the experienced aquanaut, the opportunity to live underwater is one to be cherished. After nine years of working with Aquarius, Oceanographic Field Operations Manager and aquanaut, Mark Hulsbeck says of the mission, “Saturating in Aquarius is my favorite part of the job and it hasn’t gotten old yet”. And over the years as Mark describes we get to know some of the creatures that seem to hang around the Aquarius, such as “stumpy the stingray, who has a chopped off tail. Probably bitten off by a shark. The tiger tail sea cucumber slumbering in a small grotto just off the Aquarius bow – not one of the more attractive of creatures, but loyal as he has stayed put for quite a few years. And then of course there’s Bob aka a Big ‘Ol Barracuda). He’s well known among aquanauts, hangs around the habitat, and is not afraid of divers, but then with those teeth, he doesn’t have to be.”
Dr. Jim Hench says the mission looks like a great success in terms of the science; as he puts it,” I’m super stoked about the data so far. We streamed in real-time sponge pumping rates, ambient currents, and water chemistry data. It will take months to analyze all of it, but even in the raw data stream we can get a rough idea of the data quality and some of the patterns. There appear to be times when the sponge pumping shuts down, but we don’t know why yet. We monitored conditions that may help us understand this behavior. One evening Patrick and I noticed a rapid change in the water color while out on a dive. We were due back in the habitat shortly afterward and when we came in we talked with Howard and Brian and starting looking at the data stream from the mass-spec and sure enough, the dissolved oxygen content of the water flowing out of the sponge started to dip sharply. It looked like the sponges were doing something different, so we grabbed a quick drink and then went out on the 200 ft hookah line to collect water samples for later analysis. The event only lasted an hour and we were thrilled to be able to capture some data on it.”
All and all it looks like another great mission and we all look forward to welcoming our intrepid aquanauts back to land sometime tomorrow morning.
Keep those questions and comments coming and stay tuned for our next mission, training begins the week of Nov. 5th and spashdown is Nov. 12th!
Dr. Ellen Prager
Chief Scientist, Aquarius Reef Base
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