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

I am sure the critters of Conch Reef, Florida must think their itinerant neighbors; the Aquanauts of Aquarius, are a strange lot. Aquanauts always seem to be in a frenzy – darting back and forth, carrying webbed bags stuffed with tubes, tie wraps, valves, weights, notebooks, sample bags, cords, flashlights, syringes, scissors, tape, pliers, wrenches, and god knows what else they might need before their next (inevitable) trip to the wetporch of Aquarius. Sometimes it must look as busy as the air terminal at Miami International. Today was just such a day.

We woke early, just as the first rays of neon aquamarine light spilled through the bow port window. After gobbling down oatmeal and hot cocoa we donned our wetsuits (still wet and slimy from the day before – yuck). We helped each other slip into the straps of our double tanks and headed out to check on the instruments we had placed on the reef the evening before.

During the night, we had formed an impromptu science meeting to discuss the exciting data we saw streaming across our computer screens coming directly and in real time from our suite of chemical sensors. We now wanted to test a slightly new hypothesis about the diel (24-hour) cycle of sponge and seagrass physiology and this would require a bit of “remodeling” and “plumbing” of our hardware scattered around various sites. What does that mean for our friends at Conch Reef? Well I guess, it’s a little like the signs I saw at Miami International Airport, when I flew in to be a part of this mission – our experiments for the time being are “Under Construction.” Fortunately for our fine fish friends, we are only visiting on the reef for 10 days before they get the keys to the Aquarius “condo” and the wetporch back.

Aquanaut Luis Camilli

Today we are switching to experiments involving ocean acidification by individual sponges. Sponge are animals and they breath like us, meaning they take up oxygen as they consume food particles and release carbon dioxide (CO2). The carbon dioxide combines with water to make carbonic acid. Sponges now dominate the benthic (seafloor) biomass at Conch Reef as well as many other reefs around the world. Our preliminary data from Conch Reef suggest that their respiration generates enough CO2 to be a significant factor in local acidification in the water column close to the bottom, a zone that oceanographers call the benthic boundary layer or BBL. At Conch Reef we find more than 50 species of sponges, although the giant barrel sponge, Xestospongia muta, dominates. Our data suggest that water passing through a filter feeding X muta sponge drops more than 0.01 pH units, a significant fraction of the 0.1 drop that has already resulted from the acidification of the ocean by the increase in atmospheric carbon dioxide in recent decades. Our work of the past week has revealed a similar; approximately 0.01 pH drop in the BBL relative to the overlying water column, especially at night when there is no removal of carbon dioxide by photosynthesizing phytoplankton.

Hopefully our work out at Aquarius Reef Base will help us to understand how to distinguish local acidification processes, like that from sponge respiration, from the global scale changes now occurring around the world. Only in this decade have scientists fully realized the threat of global acidification to calcifying organisms such as corals. Marine scientists around the world are now attempting to provide the information that we need to both understand and manage this important problem. Aquarius Reef Base has provided us a useful observatory from which to launch some of these efforts.

Aquanaut Chris Martens

I feel the pressure wave in my ears first, then looking through the starboard port window see a whole school of fish and floating “marine snow” move simultaneously with the surge of ocean swell which rocks the Aquarius Habitat in passing.  Thank goodness we are moored to the bottom with heavy cables, otherwise we might be visiting the surface sooner than expected!  Nonetheless, business goes on as usual, and we spend several hours graphing and reviewing the day’s scientific data and planning our dives for the next day.  I occasionally glance up at the flashing digital display of other numbers; the life support data showing available air pressure and percent of oxygen and carbon dioxide in our chamber air. 

Among many tasks on the daily checklist is to change out the buckets of soda lime for our carbon dioxide scrubbers in the Habitat.  Why do we have to “scrub” the CO2 out of the air?  Well, essentially as our bodies use the available oxygen in the air to convert sugars into energy for cellular processes – everything from firing neurons, to heart contractions, fighting infections, or digesting dinner – the result is the production of carbon dioxide as a byproduct of these physio-chemical processes referred to as cellular respiration.  Given that at any given time there can be up to six people living in a cylinder the size of a bus may give you an idea of how much respiration is going on inside of Aquarius – incidentally related to similar chemical processes we are studying on the reef outside. 

In fact, earlier in the day we placed a couple of cylindrical enclosures (about the volume of the inside of a washing machine) around various sponges and used stable nitrogen isotope tracers to see how long it would take the sponges to respire.  The enclosures, while circulating the existing water with submerged pumps, ensure that no “fresh air” reaches the sponges during our experiments.  For awhile, it looked as if the sponges were in an intensive care unit, hooked to tubes leading to a mass spectrometer and nitrate/pH sensors complete with hanging “I.V. bags”.  What we are seeing is that it doesn’t take long, sometimes a matter of a few minutes, for these sponges to respire and significantly change the pH and level of dissolved gases (i.e. oxygen, nitrogen, carbon dioxide) in their immediate environment.

Living underwater at Aquarius and conducting these experiments makes me realize just how critical (and difficult) it is to maintain the necessary balance to sustain life in an environment that is different from your own. In some ways the Aquarius Habitat can be thought of a microcosm of life on earth.  We as humans – like other animals, require a unique mixture of earth, wind, fire and water. This may seem a little obvious until you consider the broader implications of rapid environmental change we are noticing on our planet.  This little pressurized bubble called Aquarius literally means the world to me – it is a habitat that I can’t live without.

Aquanaut   Luis Camilli

Today we moved our ocean acidification study site from a seafloor site dominated by encrusting sponges to a sandy patch near Aquarius. We hypothesize that respiration by the sponges is causing the increase in ocean acidity near the bottom at our first site. Sponges are animals like us and they produce carbon dioxide when they respire. The carbon dioxide reacts with water to make acid. We want to see if there are any processes in the sandy sediments that can produce a similar effect. If we want to distinguish global scale ocean acidification from fossil fuel CO2 in the atmosphere we’ll have to be able to tell local from global scale impacts- think globally act locally!

To move the equipment to our new site we took off our fins, released air from our BCDs (Buoyancy Compensation Devices) and walked each heavy piece across the seafloor stepping only on sandy spots. We usually use BCDs to stay neutrally buoyant in the water column like a hot air balloon- this makes it possible to float around above the reef surface without touching corals and other living organisms. When you get “heavy” by expelling air you settle to the bottom but only experience a fraction of normal gravity and so it’s like walking on the moon. That’s why astronauts often train at Aquarius. You’ll see our new site on the web soon- we’ll call it Moonbase”!

Aquanaut Chris Martens

Each mission two of our expert habitat technicians are part of the aquanaut team. Ever wonder what they do down there and what it is like to be a habitat technician in Aquarius?

James Talacek is the lead habitat technician in Aquarius this mission.  He says that the primary job of a Habitat Technician (HabTech) is operation and maintenance of Aquarius.   For he and Nathan Bender (the other habtech this mission) the day starts at 6:00am when they perform a daily checklist that covers all aspects of habitat operations and ensures that all systems are ready for another day of diving.

They next act as divemasters for the scientist aquanauts, getting them out diving on the reef to work on their various science projects and overseeing their dive plans and safety.

After that James and Nate spend the day monitoring life support systems and communicating and coordinating with the shorebase crew on conditions in the habitat, daily needs, and any issues that arise. When the surface crew comes out to make deliveries, they work with them to receive supplies. They each also spend quite a bit of time in the water using rebreathers or on hookah to perform habitat husbandry (scraping, cleaning, and all general maintenance activities) and often have construction projects to work on.

The habtechs end the night with a final systems check and then get some much needed rest to do it all again the next day.

James says his favorite part of living in Aquarius is getting to see all the cool underwater life around the habitat.  Living underwater provides the opportunity to view marine life 24/7 – much better than if you were just doing a short dive from the surface.

This is Nate’s first mission as a habitat technician and here is what he has to say about it:

“It’s wonderful here.  The days are long. but they fly by – unfortunately.  Right now, we’re catching up on some improvements, so if we’re not putting in new swinging stools or feaux walls, we’re “busting rust” outside.  This experience is more than I thought it would be.  The hardest thing about being here is trying to stay focused when I’m out on hookah.  I have to remember that this is my job, and to quit staring at the goliath groupers.  Watching those guys “boom” when they eat and getting run over by a nurse shark have been awesome experiences.  On the rebreathers, it’s a different experience, I’m sure, because the marine-life aren’t as suspicious, and you don’t have bubbles masking your hysterical laughter when you are taking all of this in.”

Thanks James and Nate, keep up the great work and have a good time down there!