Life in the aquarium

I just past hour 170 of my dive, definitely the longest dive I’ve logged so far, so today I figured I would give you guys a tour of the habitat and let you know a little bit about the somewhat surreal life underwater. As I said earlier, the habitat is anchored on the bottom, midway down the fore-reef wall on Conch Reef. The reef is around 60’/20m here and the habitat sits up off the bottom, so our living depth is ~50’ (16m). This gives me 6 hours a day working at my deep sites. I can make a four hour excursion, spend 4 hours in the habitat at what we call “storage depth” to off-gas, and then make another 2 hour excursion. Because dive computers don’t work down here (They start freaking out around 24 hours and by 36 hours I think they just assume you’re dead and quit) we have to dive square tables, which limits our bottom time quite a bit, but still blows-away anything we could do surface-diving. To maximize our bottom time, each rig is equipped with a fill-whip, which is basically a high-pressure hose connected to the first stage of the regulator that we can plug in to refill our cylinders. This means we can refill without ever having to get out of the water or even take off our gear. We can fill at the habitat, and the Aquarius crew also sets up way-stations with gas – basically little gazebo’s with an air pocket and gas control panel inside and so you don’t have to go all the way back to the habitat to refill.
When we’re in the habitat there isn’t a whole lot to do, which is okay because we’re usually pretty exhausted and have plenty of data to enter and equipment to prep for the next dive. The habitat itself is about the size of a city bus, with equipment and shelves on each side of an aisle running down the middle.

View from the main cabin to the wet-porch.

View from the main cabin to the wet-porch.

All six of us sleep in the bow on bunks, which sounds crowded but I hardly notice with everything else going on. Between the slight swaying of the habitat, the cacophony of snapping shrimp and fish scraping food off the hull, and the silhouettes of fish darting around outside the window I’m usually out within 10 minutes.
The main cabin consists of a small table, our “galley” (sink and microwave) and the main control bench for the habitat. It’s the area where we spend most of our down time, sitting around snacking and watching the fish out the window. Breakfast, lunch and dinner are all freeze-dried meals (Mountain House for all you campers) which aren’t too bad, and lots of candy to graze on during down time. We also have a cold box stocked full of cheese and a stockpile of coffee and hot chocolate, which are essential when you get back into the chilly habitat after 4 hours at depth. The AC is running constantly to keep the condensation down and humidity is always around 75% in the main hold so you always feel damp and cold.

Some lab mates stopping by for a visit while we're warming up around the table.

Some lab mates stopping by for a visit while we’re warming up around the table.

The second compartment has a redundant control panel for the habitat and space for science equipment. We have a few instruments deployed to track water chemistry 24-7 as well as imaging sonar to monitor fish behavior that fill up most of this space. The main pressure door to the habitat that will be sealed when we start decompression is here as well.

Our "science desk". Did I mention space was limited down here?

Our “science desk”. Did I mention space was limited down here?

Just outside the main lock is the wet porch, a room welded onto the outside of the habitat that’s maintained as an air-pocket without any actual pressure control. The wet porch houses most of the control panels for the exterior hoses, our shower and dive gear. This is also our entrance to the reef. All we have to do is step down into the moon pool, put on our gear and we can duck under the wall and swim out onto the reef.

Two divers in the moon pool on the wetporch. This is how we enter and exit the habitat, simply gear up, duck down and swim out onto the reef.

Two divers in the moon pool on the wetporch. This is how we enter and exit the habitat, simply gear up, duck down and swim out onto the reef.

The habitat is connected by an umbilical to a life support buoy (LSB) on the surface. The LSB holds all our fresh water and has two diesel generators and compressors that pump down air maintain pressure in the habitat. In addition, this is where we get all our power (and the wireless internet signal).

All our equipment and food gets carried down to us in “pots” which basically look like large pressure cookers that are sealed to keep everything dry. The surface support team pots down all of our food and science equipment before the mission starts. Then periodically makes visits to restock anything we may be low on and pot garbage back up for disposal. Any work down here takes a bit of extra planning because almost nothing is designed to work at depth. For example, all of the computers for data collection need solid state hard drives because the pressure pushes the discs together and locks up traditional hard drives. Buttons on electronics and pressure sensitive touch pads get stuck down and don’t work, and food containers typically get a small hole punched in them to prevent the entire container from collapsing. Even diving equipment requires some forethought. For example camera housings need to be left open and potted down or we can’t get them open once we’re at depth.

One of our surface support divers delivering a pot of supplies on the wetporch. These guys are our supply lines to the outside world.

One of our surface support divers delivering a pot of supplies on the wetporch. These guys are our supply lines to the outside world.

Our biggest concern in the habitat isn’t flooding, but is actually fire. Although the percentage of air in the atmosphere remains the same, because of the pressure there is more oxygen present, so small sparks and electrical shorts can quickly start fires. Flooding is also a concern, but ranks below fire and toxic gasses. If we lose power we can seal the habitat and have enough air for the six of us to last 72 hours. Additional storage bottles outside the habitat can provide another 3 days of air so if needed we could make it nearly a full week without power. In the event of a fire, chemical spill or flooding we can evacuate through the wet porch in the stern or an escape hatch underneath the bunks in the bow. Each location is stocked with 6 bailout bottles (small air cylinders for emergencies) and we evacuate to the gazebo located directly next to the habitat (the white tent-like structure on the live webcam). The gazebo has its own gas control panel to fill breathing gasses or mix decompression blends if necessary.
Aside from a few nuances of life underwater, it’s been surprisingly easy to adapt to living at depth. I still feel a bit of constant pressure on my chest and everyone sounds like they’ve inhaled a little helium because of the density of the air down here. Other strange changes that I’ve noticed have been losing my sense of smell (probably a blessing with 6, damp people squeezing in-and-out of pee soaked dive gear all the time smashed in a small, enclosed space) and things taste more bland (probably related to the smell). Still, the hardest thing to get used to is looking out the window while you work, eat, sleep or shower and seeing all the fish staring in at you.

Splash-down

I must confess, I fully intended to get this post about training up before we saturated, but throughout a busy and exhausting week, it just didn’t happen. So, here it is now, brief little chat about our week of training in the keys. Each day started with a morning of briefings and shore-work followed by an afternoon of practicals and skills tests, and finished up with some good beers and great BBQ cooked up by our friends from the NEDU running surface support (thanks Sully! Pot us down some burgers!)

We are diving with a modified Hogarthian setup with double 100s to make the most of our time. For those who don’t dive, this setup is two tanks, each 1.25 times the size of a regular scuba tank connected with a manifold and mounted on a steel backplate. Fully assembled the rig weighs 125 lbs dry (~60 kg) so it takes a little practice to get used to the extra gear and weight. In addition to getting used to new gear, during training we spent quite a bit of time running and setting navigation lines and practicing emergency drills. We practice with the lines because during a normal dive, if you find yourself lost, low on air, or in an emergency situation, a controlled assent is usually your safest option. When saturated, the surface is no longer an option and small issues like getting a bit turned around (ask any scientific diver and they’ll tell you how easily it happens when you’re focused on collecting your data) can turn into serious situations. To minimize this risk we run excursion lines to all our primary research sites and cave-reels out from the primary sites. In addition, we run shut-down drills to practice isolating cylinders and switching gas in the event of a breakdown anywhere in the rigs. By the end of the week we were doing all of our training without masks to make sure we’re on our a game.

So, now that you have a brief rundown of our training, we get to spend the next 7 days in the habitat, which is already shaping up to be quite a surreal experience. From here on out I’ll do my best to keep up and try to post about life underwater in the next few days. In the mean time, feel free to try and catch us on the live webcam here (http://www.ustream.tv/aquariusreefbase) – the feed turns on and off intermittently and switches from interior to exterior cameras, so if its not on when you visit you can always check back.

Saturation Science

The other day I introduced our upcoming Aquarius mission, so I thought today I would take a few minutes to introduce the science behind it all. While the opportunity to live underwater and dive nine hours a day seems like reason enough to me, it can get pricey to pull off such an endeavor and “because it’s awesome” typically doesn’t get a project funded. In my previous post I mentioned  I’d be studying herbivory and grazing across a depth gradient so I thought I would briefly discuss why it’s important to understand.

I won’t spend much time here arguing why reefs are important; suffice to say, if you don’t appreciate the intrinsic value of a reef, or that ~ 10% of the world’s population depends on them for food, you may appreciate the services they provide, such as tourism, fisheries, coastal protection and natural products, which could be worth as much as $375 billion per year. Despite their various values, coral reefs are in bad shape these days and their prognosis looks bleak. Warming oceans, overfishing, changes in seawater chemistry, and more severe tropical storms are just a few of the factors that have contributed to the loss of as much as a third of world’s coral reefs in just a decade. When these slow-growing corals die on shallow reefs, faster- growing algae quickly take their place. These algae smother and kill the remaining corals, while preventing new coral from settling. The job of preventing this transition from a coral- to algae-covered reef falls to coral reef herbivores such as urchins and parrotfishes, which eat algae and maintain the open space for swimming coral larvae to settle and grow. Unfortunately, due to human impacts the speed at which corals are now dying is so fast that herbivore populations, already decimated by overfishing and disease, are often unable to keep pace with the algae growth.

A time series taken by geologist Eugene Shinn showing the same location in the Florida Keys from 1959 - 1998.

A time series taken by geologist Eugene Shinn showing the same location in the Florida Keys from 1959 – 1998.

But there’s still hope for the future. In addition to traditional strategies, such as better management of shallow reefs, deep-water or “mesophotic” coral reefs that grow between 30 m and the depths that light can no longer penetrate, are gaining attention from researchers as naturally protected “source” populations for surrounding areas. Because the deep waters above these reefs can provide a natural buffer from threats such as artisanal fishing, storm damage, and the high-temperatures that trigger coral bleaching, these reefs are naturally protected from many of threats humans have created for shallower reefs. As a result, these deep reefs may act as a sort of self-sufficient Marine Protected Area, where species survive and their offspring eventually repopulate the surrounding shallower reefs. Due to the technical difficulties of working at depth, researchers are only recently beginning to understand the role of these deep coral reefs and the processes important to their continued health. While we know herbivory is important for shallower reefs, declining numbers of herbivores at depth, coupled with slower rates of algae growth, have created uncertainty in how important herbivory is to maintaining the health of deep-water coral reefs. And that’s where our science fits in. Starting on Sunday we will begin documenting herbivore communities, feeding patterns and algae growth to understand the role of herbivores in structuring these important systems.

Lets talk about the ocean…

A while ago Nate invited me to write some posts for this blog, and so after a year of not doing that, I’ve decided it’s finally time chime in.

I work with Nate, and while he seems to have lost his sea-legs and moved to drier ground, I’ve stayed on the marine side where we started, studying coral reefs. A week from today, I’ll begin a saturation mission at the Aquarius Reef Base, a 20’ x 40’ lab located about 5 miles off the coast of Key Largo, FL, at the bottom of Conch Reef. It is one of the few remaining underwater research stations in the world and has been used extensively by scientists for dive-intensive research as well as the US National Aeronautics and Space Administration (NASA), presumably for training missions but more likely for the opportunity to create another acronym (NEEMO – NASA Extreme Environment Mission Operations).

Researcher Sylvia Earl outside the Aquarius Reef Base

Researcher Sylvia Earl outside the Aquarius Reef Base

I’ll be living in the habitat with 5 other people for a week to work on two projects: (1) studying herbivory on deep coral reefs, and (2) understanding the indirect effects of fish predators on reef herbivores. Living at depth, or saturating, means we don’t need to come up for surface intervals to off-gas. Instead we simply stay under pressure the entire time until the end of the week, when the station gets sealed up and basically turns into big hyperbaric chamber that slowly brings us back up to surface pressure. This will allow us to spend far more time in the water than we could by using conventional diving technology, while also providing the opportunity to live under-freaking-water!
So, over the next few weeks I’ll be hi-jacking the blog from time to time to write about the training, science and experience of being trapped in a steel tube with 5 other people for a week.

If you’re one of Nate’s regular readers, you probably wont see anything on R, Python, or any other programming languages from me, sorry. On the bright side, I won’t be posting any pictures of my dog either.