Thor was up early as usual beginning the daily systems check. After Thor and Roger had several conversations with the base back on Key Largo, we were told that the storm was moving towards the FL Keys and fast enough that decompression needed to be started sooner rather than later in the day and that we’d not be able to have an excursion this morning. We made arrangements with our day boat crew to come out and pick up the ADV and other equipment from the reef. We’ve started packing up all of our gear, which will be removed later today. Now, we simply wait as the AQUARIUS techs secure the habitat and begin storm preps.
The conditions on the reef have not improved today – still very murky and shifting currents. Jeremy and I staged out before 8 am and got right to work repositioning the ADV over another sponges and getting the particle feed set up. This took about 1 hour. We then we began using dye and a video camera to record how fast many other sponges were filtering seawater. It took about 15 minutes to do this for each sponge. This information, in conjunction with data on the types of chemicals in sponge exhalent water, will be crucial for determining the amounts of these chemicals sponges release into reef water and the impact these chemical have on reef health.
Jeremy and I finished our first dive around 1 pm. At AQUARIUS we downloaded data from the ADV, recharged camera batteries, changed film and had lunch. During the break I also check several of the weather website and saw images of a growing storm in the Caribbean Sea – this was not what I wanted to see. Our afternoon dive began at 5 pm and conditions were still less than ideal. Jeremy and I swam back out to the NE sites, passing Chris and Meredith doing sponge abundance counts on our way out to our research site. We set up our ADV again and then started up with the dye release video work. The strong current made this work very difficult. We were due back at the habitat soon, so we gathered up our gear and swam back along the excursion line examining sponges and other reef animals as we moved along the lines, which was not difficult as the current was pushing us back towards AQUARIUS. We staged back into the habitat just before 8 pm, racking up over 8 hours of excursion time on day 2 of our mission.
After showering, I rechecked the weather web sites and found that the storms in the Caribbean and Gulf of Mexico were getting bigger and moving closer to Key Largo. At this point we were told by the AQUARIUS tech saturating with us, Thor and Roger, that these storms, and particularly the one in the Caribbean, Charley, might force us to abort our mission. We went to sleep thinking we might have at least one more dive and then we’d begin our 17 hours of decompression needed before leaving AQUARIUS for the surface.
Got up early after a good night’s sleep- we always sleep well after a diving day. Had my Kix w/milk then it was off to do our first full experiment with living sponges. We want to understand what the role of abundant sponge species is on the nitrogen cycle of Conch Reef. Sponges process small particles of organic matter just like humans consume food. Sponges host large numbers of bacteria and we think that these bacteria help convert nitrogen in the organic matter into forms of nitrogen that may both harm and help the reef. If the bacteria make ammonium and nitrate these forms of nitrogen are like fertilizer and can help undesirable organisms grow on the reef. However if they make nitrogen gas, the same as in the air we breath, then the nitrogen can escape back to the atmosphere thus helping to maintain the low nutrient environment necessary for natural coral-algal reefs to thrive. One of our faculty colleagues at UNC-Chapel Hill, John Bruno, and his team have shown that high nutrient concentrations enhance the susceptibility of corals to diseases now commonly found in the Caribbean.
The water is not too clear today but we don’t care because the work will be done out on the deck at 50 feet depth. As we get ready to suit up, I casually check my always faithful meter for measuring oxygen levels in the experimental bottles…..Surprise! The oxygen meter is dead, absolutely stone dead. Nothing turns on, not even low voltage parts. It’s a great instrument made in Denmark for underwater use, however, today something is wrong. After an hour’s work I still can’t find the problem but suspect it’s either a charging problem or a dead battery. We decide to send the meter ashore with the NURC operations support crew from the shore base. The Navy doctor is out to check on our health and this provides the opportunity I need to send it up to get fully checked out by Dominic, our computer pro.
Sometimes, actually often, things don’t go as expected and it’s good to have a back-up plan. Plan B is to conduct a survey of the amount of sponge biomass on the reef seafloor. This data will allow us to apply the bottle experiment results to calculate the overall role of the sponges in the reef nitrogen budget. After shipping the meter off for tests ashore, Meredith and I suit up for the survey work and head out. Before the day is done, we’ve conducted four sponge surveys near the NE Way Station. We head in at 7:30 PM so as to be in before 8:00 PM. We need 12 hours downtime in the Habitat before we’ll be allowed to have another full dive day.
On the way back and at the Habitat we have some extra time for a little fun in the darkening water column. I flash around our new halogen high intensity beam lights. The fish go bonkers….At the Habitat we peer under the main lock at beautiful, bright orange corals which have begun their nighttime feeding. Their tentacles flow with the water movement as water swirls past- a continuous dance that brings them into contact with tiny food particles that they capture with a graceful withdrawal of each tentacle. Night diving is wonderful and I’m already looking forward to those planned for later in the mission.
Time to go in and get a shower and some chow!
I woke up early this morning to find the water just as turbid as day 1. No matter to me, my work in the water does not demand clear water. Thor Dunmire (the other onboard habitat technician) and I worked together to quickly complete the morning’s systems’ checks.
One team of scientists were out and diving as planned by 0800. The other suffered a minor set back due to a malfunctioning oxygen meter than measures oxygen saturation inside sponges. I was kept busy by the constant checking in and out of dive teams, recall tests, tank fills and phone calls. It’s an incredible experience maintaining and monitoring the Aquarius systems beneath the waves, not to mention the enormous responsibility of ensuring the safety of all personnel, but by late morning mother ocean was calling! Donning my gear and gathering the tools of a working diver… scraper, chisel, wire brush etc… I was filled with the anticipation felt by a child ready to enter a toy store.
Leaving the safety of the Aquarius I find myself in a 2 knot current, poor visibility, surrounded by predators and ready to perform hard labor for six hours. Conditions a sport diver rarely encounters, to work underwater in these conditions is like working on land while you are cold, tired, hungry, blind and have one hand tied behind your back.
You gotta love it, I do!
Conditions can change quickly on Florida coral reefs. Two days before we splashed down on Monday morning the water over Conch Reef was beautiful – warm and clear top to bottom. Today, however, the water looked very different. It was difficult to see my buddy, Jeremy Wiesz, when he was only 20 feet away from me. The current was swift too, and between the morning and afternoon dives the current did a 180 degree turn, which really helped make the trip back from the NE research site to AQUARIUS very easy. No tell what we’ll wake up to tomorrow.
Our experiments went well today. Jeremy and I set up our ADV (Acoustic Doppler Velocimeter) over a barrel type sponge so we could measure how much water sponges were filtering over a 24 hour period. Because sponges do such a great job filtering particles from seawater, we had to add small particles to the water coming out of the sponge so that the sounds that beam from the ADV had particles that would reflect the sound back to the receivers. We’d get some unusual spike in our data when fish would stick their noses into the sponge to investigate the particles – didn’t expect that to happen.
Dining at Café AQUARIUS is more like camping than having dinner in a fine seafood restaurant, however, freeze-dried dinners taste better today than they did years ago when I went backing packing with my family. We should sleep well tonight because the pistol shrimp are busy at night snapping their claws, which makes a noise like rain falling on the roof – a strange sensation for our temporary underwater house.