Mission & Project Info | NOAA’s Aquarius Undersea Laboratory
Mission Blog

Hi Ron.  I wish great success with your studies.

1) What instrumentation are you using for your in-situ studies?

Ron, to address our project objectives, we have assembled a diverse team of marine geochemists, chemists, ecologists and fluid dynamics experts to examine how the metabolic activity of sponges changes the chemistry of reef waters.  We are using a suite of in situ instruments, several of which are prototype instruments with the ability to make very precise chemical measurements with short sampling intervals over long deployments.  Below I have listed several of the instruments current collecting data on Conch Reef.

Tethys submersible membrane inlet mass spectrometer - developed by Rich Camilli at Woods Hole Oceanographic Institution in collaboration with Monitor Instruments with funding from various federal science agencies, including NSF and NOPP.  Working with Prof. Chris Martens, myself and several UNC graduate students, we are using this instrument to make exceptional precise concentration measurements of dissolved gases (e.g., nitrogen, oxygen, carbon dioxide, argon) and small volatile organics. This instrument cannot only measure the concentrations of these substances, but also their isotopic makeup. This allows us to use isotopically labeled tracers to identify, in real-time, the metabolic pathways being used by the various reef organisms.

SEAS in situ instruments developed by USF and SRI.  These instruments very accurately measure various dissolved nutrients, such as ammonium, nitrite, and nitrate, as well as pH.  Our collaboration with the USF and SRI team allows us to measure the contributions of sponges to nutrient cycles on coral reefs and their impacts on reef water pH.

Acoustic Doppler velocimeters - we use these instruments to continuously measure the velocity of seawater in sponge excurrent jets and the ambient currents. Combining these data with the cross-sectional area of the excurrent jets and the concentration of dissolved chemicals and particulates, we calculate the fluxes of various chemicals and organic matter moving through sponges.

Acoustic Doppler profilers - measure the speed and direction of currents at various heights above the bottom.

Laser-based Particle Image Velocimetery (PIV) - this in situ system, developed by Cal Tech scientists is being used by project scientist Dr. Jim Hench (Stanford University) to measure small-scale fluid motions in a plane positioned across sponge excurrent jets.  The ADV measure fluid motions basically at a single point in the sponge excurrent jet.

2) Have you developed your own instruments or have you adapted the usual analytical instruments to the aquatic environment?

Several of these instruments such as Tethys are based on relatively new technologies, while some of the other instruments, although based on well tested analytical methods, have undergone significant modifications to enhance sensitivity and the ability to operate in the ocean.

3) If adaptations were made, what were they (in general)?

I am not the right person to answer this question.  I would be better answered by the groups that developed the various instruments, such as Rich Camilli for Tethys, Prof. Robert Byrne”s groups at USF for SEAS instrument, etc.

Thanks for your interest and questions.

Cheers, Dr. Niels Lindquist, aquanaut

Richard asks: In your research involving rebreathing systems do you ever consider the artificial gill? I first heard of it in the 1960’s . A thin membrane of silacon 1000th of an inch thick allows oxygen to flow though it from the water. I read about it again in 1985. A back pack model was shown in a British dive magazine. I wrote to Aquanautics Corperation in 1993 about their product and learned that they were using the membrane in fresh produce packages to remove oxygen from the fruit and vegetables, but there was no mention of using it as a breathing apparatus. Have you heard any news about the artificial gill?

Dear Richard

This is not an area that our operations and diving experts are familiar with. May be something out there, but not that we are aware of or are working on. Sounds pretty science fiction like…though would be great if it could come to fruition.

Ellen Prager
Chief Scientist, Aquarius Reef Base

Zack Davison asks: What do your need for an everyday diver to dive the underwater habitat? I’ve been a diver for 3 years now, I’m a jr. open water, soon to be jr. recuse, and I’ve my jr. advance for 2 yaers now. Who do I need to contact about that? I think it would be an incredible sight to see and i could tell my science teacher about it.

Hi Zack!

Thanks so much for you interest in diving at Aquarius.  We would love to be able to bring enthusiastic young divers like you to see Aquarius, but unfortunately for safety of our operations and research, we don’t regularly allow the public to dive at Aquarius.  In fact, the Aquarius sits in a designated research-only zone within the Florida Keys National Marine Sanctuary to protect the Aquarius, our work, and the habitat and fish that our researchers are studying and for safety. For now, you will have to join us virtually on the web and watch for broadcasts that we will be doing later in the year…..keep up the diving and who knows maybe one day you can work with us or become an aquanaut doing science or developing new underwater technology.

Dr. Ellen Prager

Chief Scientist, Aquarius Reef Base

Ron Peters Asks:Breathing mix question. What atmospheric mix are you using inside the habitat? Are you using the standard 21% or a richer mix? Is the same breathing mix used in the tanks during the aquanauts excursions outside the habitit? What is the deco profile for recovery of the aquanauts at the end of the mission? 

Dear Ron

Aquarius, with its open ambient wet porch, has a constant air bleed throughout a mission, good old 21% like we breathe on the surface.  The partial pressure of oxygen however is .45ATA and not .21 ATA because of the 47′ depth inside Aquarius.  Nitrox or enriched air could be used for a habitat mix and diver breathing gas, this has been done in previous habitats in the 70’s with depth ranges of >50′.  Mixes were selected to provide partial pressures of oxygen similar to atmospheric air at .21 ATA for that depth-called “normoxic” mixes.  

Aquanauts are breathing air in their tanks, we have two high pressure compressors on the Life Support Buoy overhead, with 86,000 cu ft of storage air in flasks on the seabed.

Decompression, which was completed at 0830 yesterday morning, takes 17 hours, we close the swinging door to the wet porch, then slowly exhaust the atmosphere through an umbilical to the surface.  Once we reach 0 FSW or “surface” inside Aquarius, we pressurize back to hatch depth of 45 FSW, open the door to the wet porch, and are greeted by two escort divers for a two minute ascent to the real surface on a short repetitive dive.

Craig Cooper

Aquarius Reef Base, Operations Director

e. wohlenberg asks: As I was watching the aquanauts “go home” after a day’s work, a question occurred to me.  Must wetsuits, etc. be rinsed and dried each day, or may they stay soaking in salt water until the next day’s work?  Thanks.

Great question! The Aquanauts work long and hard in their wetsuits and they do get a bit “funky”. Our wetsuit cleaning procedure has them removing the wetsuit and doing an initial rinse in salt water. They are then rinsed in a bucket filled with fresh water. After that, the wetsuits are dipped in a bucket of fresh water that has an enzyme solution called Mirazyme added to it. The Mirazyme is the key. It kills the stink making bacteria. What a relief!
The wetsuits are hung on hangars to drip dry. They never get totally dry because the wet porch, where they are stored, is at 100% humidity. Another interesting fact is that the wetsuits compress with depth, so they stay compressed throughout the mission. This definitely shortens the life of the wetsuits.

Mark W. Hulsbeck
Oceanographic Field Operations Manager, aquanaut