In search of the Rosetta Coral

We set out for Darwin and Wolf with a goal of collecting 15 coral samples. Long samples. Because in our field, size does matter. The larger the coral, the longer the core, and the longer the climate history. To capture the past couple hundred years, we were searching for a coral that could give us a 2 meter long sample. The Rosetta Coral.

Fortunately, our lab’s mascot “Coral” traveled all the way from Tucson to cheer us on.

Photo by Gloria Jimenez

We cruised to Wolf first to get our feet wet where the conditions are typically more calm and better for diving. We returned to the reef where we took samples back in 2010, and broke out Julie’s brand new pneumatic drill system to give it a good ole test drive and make sure everything was working properly and efficiently.

Because if we were going to reach our goal with 5 days of diving, efficiency would be key.

Photo by Stephan Hlohowskyj

The drill runs off of compressed air, which can be a major logistical challenge with the strong currents and deep reefs at Darwin and Wolf. To power this type of drill, there are only two options: power it from scuba tanks or an air compressor from the surface, or bring extra scuba tanks down to the bottom to power it.

With many tanks of air needed to take a 1-2 meter coral sample, bringing tanks down isn’t ideal, especially when they begin to float away as you use the air in them! But the other option, though seemingly ideal, requires the boat, or a zodiac or panga, to be anchored right above you, with enough compressor hose to make it down to the depth of the coral without tension. And if there is current or swell, that possibility goes right out the window…as the hose and boat gets tossed and yanked around like a rag doll.

And rough conditions is something these islands do well. When we arrived, the Queen Mabel tried to anchor at the site, and before the anchor could even be set, the boat heaved and the huge steel anchor chain snapped in 2. And the anchor was lost. The first casualty of the trip….

On top of the rough conditions, the large corals at these islands that we want to sample are unfortunately also deep. Typically corals that we sample are in shallow water, but here the big ones are found around 50 feet. This not only means lots of compression hosing, but it also means that lots of nitrogen buildup in our bodies. With 3 to 4 hour long dives per day (dawn pre-breakfast dive, after breakfast dive, and 1-2 afternoon dives), we’re all pushing our decompression limits every day.

The drill. Photo by Julia Cole

So we brought a tank of air down with us on the dive to test the drill, hopeful that the drill would be strong and efficient. We were all a bit relieved when we found that with this tank the drill cut through….a few inches of volcanic rock! The rock is much denser and tougher to drill than corals, so we ended the dive hopeful that we’d be able to collect samples without needing too many tanks of air. Fingers crossed…

Drilling some rock like it ain’t no thing. Photo by Jennifer Suarez

Photo by Jennifer Suarez

For the remainder of the day, while the captain and crew searched for the lost anchor, we went on a search of our own to find the corals we drilled in 2010. We wanted to photograph the health of these corals to show their recovery following the drilling. As a marine ecologist turned paleoclimatologist who went from monitoring health of reefs to poking holes in them to study climate, I was particularly keen on seeing their recovery.

After coring, we fill the holes we create with cement plugs that prevent other organisms from coming in and killing the corals from the inside. These plugs also provide a surface for the coral to re-grow, and many have documented the recovery of corals cored in this way. But I was excited to see this for myself. You know, to sleep at night…

An example of a plugged sample from this trip. Photo by Julia Cole

But we looked and looked and looked all around the GPS coordinates of the corals sites, and could not find them. Knowing that we that we likely swam by the corals a few times and couldn’t find any evidence of drilling, I’m happy to know that the corals must have recovered and grown over the holes.

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In the wee hours of the morning we cruised the remaining 4 hours to Darwin. I watched the sunrise as we became closer and closer to the picturesque arch off the southeast side of the island.

We cruised around the island to start in the somewhat calmer Arrecife Escondito (“Hidden Reef”) to start to search for large corals to sample.

Prepping for the dive. Photo by Julia Cole

On our first pre-breakfast dawn dive we found a coral that was around 2 meters tall and started drilling. We were off to a great start, but would soon come across a number of hurdles with the drill, slowing the coring process. Although a frustratingly slow progress, we continued moving forward (rule number 3!!), and 5 dives and far too many tanks in, we finally got 2 cores out of this coral. Sadly, a big part of our slow progress from this coral is that it turns out it was only an ~half meter coral head growing on top of a large rock. 😦

We named this coral “heart of stone” and continued on in search of the Rosetta Coral.

“Heart of Stone” coral with the 2 coral samples plugged. Photo by Gloria Jimenez

We got one more half meter core from another core at this site, but unfortunately this core was riddled with boring clam holes. So we aptly named this sample the $50k pencil holder.

While Julie and I did one last sweep of the reef in search of large colonies, we ended up in a scene straight from Blue Planet (or Finding Nemo!). Suddenly, the ocean went nearly black as we were surrounded by a school of thousands of fish. As they’d move back and forth, the sides of their bodies would temporarily glisten in the sunlight, making shapes in front of us. No directions to the Sydney Opera house, but they were clearly being chased by something. Something big. My excitement quickly faded as I waited for whatever it was chasing them to come out of the darkness. Fortunately, what appeared were HUGE mackerel. It was feeding time! An incredible experience!!!

Meanwhile Stephan and Gloria went to set a temperature logger by the first coral, and in doing so, Gloria got bit by an angry eel 😦 Fortunately, she didn’t lose her thumb and it didn’t hit a major artery, but she is left with a bad wound and will likely need surgery to fix a tendon. But let me tell you, she is one tough chick!!

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After a satellite phone call to the islands for advice on Gloria’s thumb, we decided to move on to try to find the rosetta coral on the other side of the island at Arrecife Antigua (“Ancient Reef”). On our first dive, I found two nice, large corals…the second was easily 2 meters or more. I was so excited when I found it that chasing Julie down to show her against the current suddenly didn’t feel so hard (thank, you adrenaline!). I felt a little little like a little kid at Christmas! “Mommy, mommy, look what I got”!!! jaja 🙂

We marked the corals with diving safety sausages so we could return and start drilling them after breakfast.

Tagging the first drilling target at Aricife Antigua: a ~1.5 meter, but solid head

After breakfast we set out to anchor the panga and start drilling the largest coral. But our excitement quickly turned to doubt as it became unclear whether we’d even be able to drill. The current had picked up dramatically, and conditions were now dangerous and bordering on impossible with all of the drilling equipment.

Once the panga was anchored, Julie and Stephan rolled out of the zodiac upcurrent of the anchored panga, and were quickly swept down current to the panga. Grabbing on, the idea was that Roby would pass them the drilling gear and they would safely descend down the anchor line to the coral. But with the drilling tools, which easily weigh around 50 lbs, they could not even fight the current to the anchor line. Stephan was being dangerously pulled in two directions, tools in one hand and anchor line in the other. Impossible.

Admitting that he’s never felt so close to drowning, we clearly had to rethink the logistics for this site and decide whether we would even be able to drill. The next dive, we decided to forget the tools for now, and just go to the bottom with the drill and one tank to see if it would even be possible to drill.

We went up-current of the coral and tried again. This time with Stephan hugging the tank and regulator for the drill and Julie holding the drill and tubing. Rolling off, they tried to swim straight to the bottom and to the coral to avoid getting swept away to sea by the strong surface current. Fortunately, they made it, and found relatively calm conditions (comparatively) at the bottom and were able to start drilling.

But unable to get the tools down safely by the dive team, we had to drop them from the surface, guiding them as much as possible by rope. Talk about unideal conditions, but it worked!

So from here we started a new rotating drilling team. Each new person in the water would craddle a scuba tank, roll in, and plummet to the bottom as quickly as they could, replenishing the air for drill and relieving the drill team (who were also running out of air).

And we’d bring the empty tanks with us up as we surfaced. Well, that is until one dive when I went to change the regulator to a new tank, and the empty tank slipped out from the reef and floated to the surface. Fortunately, the zodiac saw it and grabbed it. It worked so well in fact, that we started doing that for the other tanks. Well, that is, until one went missing…

Loading the scuba tanks for our dawn dive. Photo by Gloria Jimenez

Stephan and Roby break a piece of sample out of the coral head. Photo by Julia Cole

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This system worked very well and we fell into a groove, repeating this strategy dive after dive for the next 2.5 days. We fought an endless battle with the drills seizing (despite our endless efforts to oil them after every dive). Seawater and drills don’t play well together. Fortunately, we had an extra drill and at one point while I was fighting the drill, a new, powerful drill was quite literally sent to me from above. A gift from…well the drilling gods I suppose.

On the last dive, Jennifer and I wrapped up the drilling and packed up the gear. We had decided as a group on the surface that it would be best just to fill the haul bag with air and let it ascend to the surface. After 20 minutes, they’d be on the lookout for it at the surface.

But getting the tools together took the last remaining energy we had, and by the time they were finally ready to go, I was running out of air. I headed to the surface with the last tank in my hand and watched as the haul bag, carrying all of the tools, plummeted to the surface, breached, leaked, and came plummeting back down. I had to dodge the 50+ lb bag from my safety stop. Take 2. This time the zodiac was on it. As soon as the yellow bag hit the surface, I hear the zodiac speed above me and see a hand reach down and grab it. Phew.

It was absolutely exhausting, but we got 3 cores out of this head…one of which was 2.5 meters long!! We did it!!!

2 meters here we come! Photo by: Gloria Jimenez

And we named this coral “Rosie”, short for Rosetta of course.

“Rosie” Photo by Gloria Jimenez

We did two last dives to look for more potential corals (for future trips). On the last dive, we headed to “deep” water to collect a sample of the cold water coming up from the deep around this site. And at only 80 feet, for the second time in my life I felt nitrogen narcosis. Suddenly the world started moving a bit slower and I felt drunk. I immediately looked at Stephan and signaled that I was going to move shallower. The repeated dives had finally caught up with my body and I was DUN. Until next time, Darwin!

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