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

While the scientists have been pursuing their studies, our expert habitat technicians have also been working hard to ensure the safety of the researchers and that all life support systems are working and on target, regularly checking in with the shore based crew, and performing maintenance tasks both inside of Aquarius and on the outside.

And in between their duties, all of the aquanauts are enjoying the spectacular scenery undersea and what life is like living in an undersea research station. After long hours and very early morning diving, rest is welcome and sleep sound. Most aquanauts say they sleep well in Aquarius – unless there is a snorer among the team, but even then sometimes tiredness overcomes the nightly noise.

Meal times in Aquarius are an important part of the day. Aquanauts that spend six to nine hours a day diving expend a lot of energy and need to refuel their bodies between dives. Meals are also a time for aquanauts to laugh over what the high pressure atmosphere can do to food containers that contain air or how things tend to taste bland. Aquanaut on this mission and Aquarius oceanographic field operations manager, Mark Hulsbeck says that his favorite food down below is cheese quesadilla’s with lots of salsa. Although he also reveals that he tends to put hot sauce on most of his food, even when living at the surface. From my missions as an aquanaut, I happen to know that chocolate still tastes particularly good down below. Hot chocolate and soup are common favorites. There is no oven or stove for safety reasons, but there is a microwave, cooler, and instant hot water maker. Most meals consist of freeze-dried foods that are reconstituted with hot water, including eggs and bacon, a variety of beef, chicken, and pasta dishes, and even deserts. And every once in a while a diver may make a special delivery to the aquanauts – such as pizza.

Stay tuned as the aquanauts wrap up their science in the next few days, prepare for decompression and the return to a landlubber existence.

Dr. Ellen Prager
Chief Scientist, Aquarius Reef Base

Patrick Gibson, aquanaut

And while landlubbers are getting a great view of what life is like down below from the streaming web cams and blogs, the aquanauts are enjoying the surrounding scenery as well. Lead habitat technician, Mark Hulsbeck finds the view especially interesting at night… “waking up in the middle of the night and looking out of the bunkroom viewport, you never know what you’ll see. The first night, I saw a large pink moon jellyfish undulating past the viewport – hard to tell if I was dreaming or not. In the morning I awoke to what first appeared to be a nuclear submarine blocking the viewport. Turned out it was the larger (300 lbs) of two goliath groupers that have taken up residency at Aquarius. Too cool!.”

And you never know what might happen when you are out diving…..aquanaut Patrick Gibson found this out, relaying, “I had a big green seaturtle come right up and check me out today. He also swam over to inspect my instruments, the “turtles.” He came right up to us without any fear or hesitation. Part of me thinks that with the double tanks on my back and the instruments looking the way they do that he may have thought he fit in with us. It’s refreshing to have those big animal encounters down here – it really brings things into perspective.”

All of the aquanauts are enjoying the extended time for diving that living in Aquarius allows and the unmatched view from the world’s only undersea research station.

Dr. Ellen Prager
Chief Scientist, Aquarius Reef Base

Sleeping with the fish,
Howard

For the scientists on this mission, they have the luxury of time out on the reef to study how sponges change the surrounding water chemistry. They are sampling before dawn and up until midnight, and taking their time getting the measurements just right. And on this mission, they are also testing what may be one of the only and smallest underwater mass spectrometers in the world – a high tech instrument to measure a suite of substances in the water. For the scientists it is also a chance to observe the coral reef ecosystem around the clock and simply watch as conditions change and organisms interact. The Aquarius undersea habitat provides them time and access to the coral reef, a luxury most coral reef scientists can only dream of. Dr. Brian Popp says that so far what he enjoys the most is, “After dark the yellow tail snapper hang out right by the view port next to the dining room table and we can watch them feed. It is so cool to see little zooplankton trying to swim away and then bang, they become dinner. Really, though the science we get to do here is so unique that it is really the best part about Aquarius”.

Our habitat technicians work alongside the scientists in Aquarius to keep them safe, sound, and enable them to do their research. On this mission Mark and Larry are in Aquarius and working closely with a surface crew to monitor the life support systems, make sure everything is working properly, and keeping the habitat running smoothly (this usually includes a lot of scrapping or scrubbing of algae and other organisms that like to grow on the habitat). And taking a bit of time, I’m sure, to check out all those fish staring in at them – particularly that giant goliath grouper that has been hanging around.

For all of the aquanauts living undersea also comes with its challenges, from living in tight quarters with five other people to eating food under high pressure. Humor is a must when you are living beneath the waves. More on this in blogs to come as we check in with the aquanauts over the next few days.

Dr. Ellen Prager
Chief Scientist, Aquarius Reef Base

Patrick also today managed to “talk” over the internet with more than 70 elementary school children in western Dade County! He gave them a virtual tour of Aquarius on the inside while our Rolex Scholar (Brenna Mahoney – see the latest issue of SCUBA Diving magazine) gave a video tour of the outside. Jim has a hot date with a sponge at midnight tonight, but I’ll let him tell you all about it in his journal entry a bit later.

The most excellent Aquarius staff set-up the Navy Camera at one of our study sites so check out that new web cam link – look for Howard and I at 05:00 tomorrow.

Aloha, Brian

Howard signing off from 50ft below!

The overall goal of our research is to quantify sponge impacts on coastal N cycles. Previous work has identified high rates of N transformations within sponge communities. These include nitrification (i.e., the chemolithoautotrophic conversion of ammonia to nitrogen oxides), dissolved/particulate organic N uptake and degradation, and potentially N2 fixation and denitrification (i.e., the bacterial-mediated respiration of organic matter using nitrogen oxides as electron acceptors in lieu of oxygen). Thus, marine sponges may be adding or subtracting bioavailable N from coastal systems. Our initial investigations of N cycling in sponges demonstrated that they play a major role in the N budget of coral reefs and other shallow water tropical ecosystems (see AQUARIUS Mission 4 August 15-24, 2005 and Mission 6 17-25 September 2007). This mission will examine the role of sponges in the coastal N cycle by (i) using in situ methodologies to construct accurate N budgets for sponges that will identify them as nutrient sources or sinks, and (ii) to examine environmental controls over sponge mediated N transformations. The net impact of sponges on biogeochemical N cycling in coastal environments is largely unknown. Our research program is the first to use in situ methods to quantify the nitrogen cycling in sponges and the resultant flux of DIN and dissolved organic nitrogen from sponges.

Of paramount importance in calculation of chemical fluxes in the oceans is linking the magnitude of the water flow transporting the chemicals with real time measurements of the substrates and products of biogeochemical reactions. During our mission, we will measure sponge excurrent pumping rates using acoustic Doppler velocimeters (ADVs) on a variety of sponge species. Our in situ data collected over the past three years have documented sponge pumping rates as great as 100,000 L seawater per day per L of sponge tissue, and sponge excurrent velocities > 25 cm/s. We will use newly developed underwater in situ membrane inlet mass spectrometry instrumentation that makes possible extremely sensitive and rapid measurements of N2, Ar, CH4, O2, CO2 and other trace gases. These data will be combined with discrete samples on which we will measure inorganic nutrient, total dissolved inorganic carbon, and nitrous oxide concentrations as well as the stable isotopic compositions of nitrate, nitrous oxide and total dissolved inorganic carbon. A major goal of our mission will be to compare pumping rate data of dissolved oxygen, total dissolved inorganic carbon, and various N species in the sponge excurrent plume vs. the concentration of these species in the ambient water surrounding the sponge. With these data we can measure the net chemical flux for several sponge species to determine the impacts sponges have on coastal N cycles.

We now recognize that sponges play a crucial role in the nutrient balance of coastal environments because they are abundant in tropical, temperate and polar habitats, they process tremendous amounts of water, and they can host abundant and active microbial populations. The impact of sponges on biogeochemical cycling in these environments however, is largely unknown. The information we collect on the sponge species living in proximity to AQUARIUS is likely to have broad implications for nitrogen biogeochemistry in coastal ecosystems with abundant sponges. This research is supported by the National Science Foundation (OCE-0624406 to Christopher S. Martens and Niels L. Lindquist and OCE 0624703 to Brian N. Popp) and NOAA/NURC through the Coral Reef Alliance.