As a general rule under normal conditions sat dives tend to be around 28 to 30 days on average and some contractors will restrict sat divers to no more than 182 days of sat in a 12 month calendar year (Diving Medical Advisory Committee). As for longer sat dives, there’s a history for sure of longer and deep sat dives, one example is a COMEX diver did a 2300 foot sat dive that lasted 43 days in 1992 (I think it included decompression but not sure). Also, the longer they go the harder it is to support with logistics, personnel etc… as you know, and can quickly wear down the crew and the divers. Medical conditions become more prevalent like ear infections, skin infections and skin conditions etc…
I’m writing from a depth of 48 feet below the surface on the first night of Aquarius’ fourth mission of 2011. I am in the habitat with my fellow Habitat Technician James Talacek and the science party. The first day of this mission went as first days go with a few minor issues to work in the morning and the start of saturation by mid day.
The Aquarius crew was off the dock on Research Vessel Sabina at 0830 this morning. We finished offshore checks and some compressor maintenance by 11 a.m. and then James and I dove to the Habitat. I completed routine pre-mission checks while James swapped out a leaking valve before we committed to saturation around 12:40.
The first day of a mission for Habitat Technicians is a busy one as we prepare the habitat for operations and as a home. For scientists, especially first timers like Claire and Doug in the Habitat with me now, the first day is a day of learning about their new home and a new way of diving seperated from the surface.
We have had a great start to the mission, and as the team beds down for the night and the fish dance in the viewport, I’m looking forward to our time beneath the sea.
Thank you all for following us on this mission.
-Saul
By Joy Leilei Shih
I remember the exact moment I saw the email from my advisor in my inbox, asking if I could come to Aquarius for three weeks. I was ecstatic, and certain this was the kind of opportunity that makes the signature grueling grad student lifestyle worthwhile. It was everything I imagined (and hoped) it would be! After making the long trip over from University of Hawaii, I met the other members of the team, primarily from UNC Chapel Hill and Wilmington. The entire group was bright, energetic, and a lot of fun! The first week of three was a lot of prep work, which included building different components for experiments, setting up lab space, collecting sponges and bringing them close to the habitat, and bringing instruments down to the sea floor. We had between three and five dives every single day, and I could not remember the last time I had been this exhausted! On most nights I must have fallen asleep the instant my head hit my pillow. But one could not ask for a better “office”. Having dove around the world since age fourteen, I was stunned by the color on the reef and the amount of life! The diving on Conch Reef is spectacular. I was treated to the abundant presence of Christmas Tree Worms in every color, one of my favorite animals. For those less impressed by invertebrates, we also saw a manta ray, dolphins, sea turtles, a nurse shark, lots of barracuda, goliath groupers, eagle rays, huge lobster, moray eels, lion fish and all the other amazing life one can find on a Caribbean reef!
The habitat itself is a fish magnet, not to mention a NASA astronaut training facility! While in the water, it is immense fun to peek into the windows at the dry humans inside. It’s basically a reverse aquarium! The inside is about as spacious as a school bus. It’s nicer than you’d think, with workspaces, a kitchen-like area, and a sleeping area with six beds. There are emergency sources of air everywhere, and it’s super fun to go in and out of the habitat by swimming up through the wet porch.
Our research focused on the role of sponges in the nitrogen cycle (especially DIN fluxes). Sponges pump and filter vast amounts of water and are a significant portion of the benthic biomass around the Florida Keys. In particular, we are interested in whether sponges significantly contribute to DIN through respiration of DOM, and also if sponge-hosted microbial nitrogen gas production is an important sink for coastal environments. This exciting project consisted of a comprehensive collection of instruments, including MIMS, SEAS II, NOx M-SEAS, ADVs, Sea FETS, Aquadopps, AADO optodes, a radiometer, and SeaBird CTD/DOs, not to mention instruments at land-based labs at multiple institutions that will give us a better overview of these processes than ever seen before. Just imagine the underwater cable management!
The staff at NURC was awesome. They clearly take safety and quality of work very seriously, and I was continually impressed at how everyone always had smiles despite prohibitively long hours and physically demanding tasks daily! They felt like friends, and I’ve never felt safer, despite never having done nearly this much diving in my life!
I’ll never forget my first visit to the beautiful Florida Keys, and it will be an experience hard to beat!
….another day in the office. Today was moon jelly day- they were everywhere in the upper water column, fortunately less of them down near the bottom where we were working. Moon jellies pack a real punch with their stings so we try to avoid them completely.
This morning we set up and ran a CO2 production experiment, we call them incubation experiments, with a sponge that we believe not only acidifies the water column, but also hosts microbes that transform fertilizer nitrogen, that is ammonium and nitrate, into harmless N2 gas. The best part of the work is that we get to watch these processes occur live while living in the Aquarius Habitat. Our membrane inlet mass spectrometer (or MIMS) measures the production of CO2 by the sponge as it respires and also N2 gas production. Actually our MIMS cam measure all of the dissolved gases that we are interested in on this mission and can also measure light hydrocarbons, including those released during the northern Gulf of Mexico oil and gas blow-out last year. All of the data is relayed in real time to our computers inside the Habitat where we watch and record the changes. Having an undersea laboratory allows us to perform our experiments right out on the coral reef without disturbing the sponge or the ecosystem.
We’ve come back into the Habitat for the night and will plan our activities for the tomorrow. We’ve set up an exciting experiment to measure the CO2 emissions for an overnight period from a very large barrel sponge, the species that dominate the benthos (bottom dwelling critters) on Conch Reef. I’ll post some photos of all the equipment and experimental set-ups on the Aquarius Reef Base web site.
Now it’s time to get some rest as we get ready for the last full science day. Decompression starts on the 17th and goes on for 17 hours and so we are racing to the finish!
Today will be a great dive day. All of the 17 instruments used in our ocean acidification study are working and we are collected a growing data set. Some of the instruments are autonomous as we set them up at the beginning of the mission. These include the pH instrument at the top of our vertical array that rises 5 meters up from the seafloor and the optodes that measure changes in dissolved oxygen concentration along the array. We also have a mass spectrometer and a SEASII pH analyzer sitting on the bottom next to the vertical array.
We are also swimming around with several instruments- we call them “toys” – that we can deploy at will for quick measurements at whatever sites we choose. Several are brand-new prototypes just built for testing here at Aquarius Reef Base.
While we swim we also have fun watching the activities of all the ocean life surrounding us- the big goliath groupers like to chill out on the sand patch next to Aquarius for a little rest after the night’s fishing. The permits, beautiful game fish, are chasing after each other while the creole wrasses swim around like kids on a playground. There are lots more lionfish on the reef this year- we found seven in one crevice out at 90 feet at the end of the Ridge line.
Well, it’s time to dress out and dive- back to work!!!
Signing out, Aquanaut Chris