Friday, December 27, 2013

Mission Accomplished


1,002 nautical miles. That’s how far we traveled without using a drop of fuel. A steady trade-wind breeze, a solid vessel, and a little sailing know-how powered those 1,002 nautical miles.

A graveyard of dead coral makes for an eerie scene. 
Photo: Hanny Rivera
Here’s some more numbers. 29 meters of coral skeleton drilled. The species we sampled grow roughly 3 millimeters per year. That’s just shy of 10,000 years of coral growth that we drilled through. The longest core that we collected is 120 centimeters, meaning the oldest skeleton we drilled into may be up to 400 years old! And to collect all these samples, we each spent about 20 hours underwater on SCUBA – perhaps a modest number, but remember we are still air-breathing land mammals.


And one more number. 4 new friends, the crew of Sea Dragon. On a boat, there is no personal space. You know where everyone else is, and everyone knows where you are. We do everything together. No secrets, no time alone, no escape. Cram 8 people on a boat for 3 weeks, and it would be no surprise if everyone scattered in opposite directions as soon as we stepped on land. But that’s not what happened. No one wanted it to be over. Our last dinner all together on Curacao was one of my favorite memories of the trip. Thanks captain Eric, first mate Shanley, and deckhands Mitch and Nicole for being awesome!

What’s next? Over the coming months, the cores that we collected will go through a CAT scanner at WHOI. Our lab will then begin to piece together how and why the growth of Caribbean corals has changed over time. Ultimately, this will help us understand and predict how Caribbean reefs may fare in the future.
A beautiful reef of living Acropora - unfortunately 
a rare sight. Photo: Pat Lohmann


Our 20 hours on these reefs was just a tiny peek at Caribbean reefs. Yet we saw some truly beautiful corals, a few mysterious creatures that we are still puzzling over, and reefs full of fish. But we also saw some barren reef-scapes, devoid of fish, a graveyard of dead coral grown over by algae. Seeing these contrasts first hand is powerful. If we can learn something about what has driven these changes in the past, and how Caribbean reefs may change in the future, all our hard work is well worth it.

- Tom DeCarlo

Thursday, December 26, 2013

Archibald the Beaver dives with the Cohen Lab


In addition to our science team and crew, there is a special inhabitant of Sea Dragon. His name is Sir Archibald Munchingham, a cunning and amusing little fellow who came aboard as stowaway near Niagara Falls during Sea Dragon’s last transit in Canadian waters. Known as nature’s engineer, Archibald’s company during our trip as been extremely fortuitous as the beaver is also MIT’s mascot and as coral researchers we study a special type of marine engineer.
Archibald joins Alice on a dive. Photo: Tom DeCarlo

Archibald’s thirst for adventure and mischief has kept us on our toes during our voyage, for he often appears in unexpected places or is found scurrying among the deck or through our food stocks. His most recent hiding place was inside our bread maker, no doubt trying to gather the last crumbs from Alice’s latest creation. As we prepared for our last set of dives on the lovely island of Curacao, Archibald nuzzled up and asked if he could come along to explore the wonders of the sea. Naturally, we agreed and so began Archibald’s first scuba diving voyage to core corals. We’ll let him take it from here…

I had heard so much about the ocean from friends that I was anxious to finally experience this majestic landscape for myself. The team of scientists we currently have on board certainly seem to like swimming in it a lot, for every morning they awake bright and early and after a scrumptious breakfast – of which of I usually get a yummy side plate – are off carrying and moving all sort of heavy cylinders and funny looking jackets with hoses that dangle everywhere (I think I heard one of the deck hands call it SCUBA gear). I finally worked up the courage to ask them if I could come along and see what all the fanfare was about and thrilled when they agreed.

I was carefully placed in a Ziploc baggie and attached to an even larger bag that had a whole array of long tubes in it and which, judging from the looks of the young man carrying it, was rather heavy – I hope it wasn’t from my eating so many pancakes that morning… A short but bouncy dinghy ride later all the clattering of tanks around me told me we had arrived at the “dive spot.” I was beside myself with joy and sneaked a tiny nibble at my enclosure. I was then plunged into the water, cool and refreshing, though salty, very salty - certainly not as pleasant to drink as the crisp river waters I’m accustomed to.
Archibald oversees coral drilling. Photo: Alice Alpert
The ocean was just as I had always hoped, magnificently beautiful and busy with tiny little fish darting every which way. There were also large colorful rocks that appeared to have tiny circles and tentacles protruding from the surface. I believe these might be the famous “corals” team science had discussed at length most evenings over dinner. My bag landed softly on a sand patch and I watched as the divers began to assemble the tubes that accompanied me into a long rod that was then attached to what looked like a silver pistol.

They placed the rod atop of a big coral rock and it began to spin, as it let out a shrill shriek that made me jump with surprise. There was plume of white powder that surrounded the spinning drill as the divers pushed down on the handle and began to core. I watched the operation with a mixture of awe and curiosity, trying to determine what the scientists were doing as they removed white cylinders of coral from the colony and added more rods to their drill.

About halfway through, the scientist Tom came over and asked if I wanted a closer look. I nodded furiously while I holding on tightly to the little log that I always carry with me.  I scurried up his hand and he swam me over to the action. Up close, I could tell this was no easy task. The other diver, Alice, was grasping a nearby rock tightly while she pushed with the other arm on the drill handle and pressed the trigger. I asked if I could try my hand at this drilling business and Alice swam aside to give me the seat of honor. I grabbed the drill bit and braced myself. I pressed the trigger with all my might but it only barely budged. The scuba tank that powers it was out of air.

Luckily, one of the other science members was at the surface ready with a new tank which sank gracefully into Alice’s hands as she let the empty one go and it rushed to the surface, where it was quickly recovered by our snorkel support. Once recharged, I pressed the trigger again and the bit whirled away. But oh boy! It was so tough to keep it going for a tiny little beaver like me! After a minute or two I decided I had had enough and let Alice continue with her work. Tom, continued his tour and showed me how they tag the corals they drill with a bright yellow tag so they can return to it in the future and showed me gleaming white logs that are the coral cores. Once the core was finished, I helped the team inspect the drill hole to make sure everything was out and then we patched it up nicely with an epoxy plug. Despite the invasive operation to the colony looked no worse for wear. I then spent a few minutes exploring the reef as the scientists gathered all their gear.
Archibald helps label a coral. Photo: Alice Alpert


I swam in and around sea fans and coral rubble, following tiny bright fish that looked  confused upon seeing me. I suppose they had never seen a beaver before. I quickly made friends with a tiny blue fish with electric blue spots and a vivid yellow tail. She said she was a damselfish and showed me to small patch of algae that was apparently her garden. As I watched her trim away at fluffy leaves that swayed rhythmically with the waves, a large fish swam by and hovered over us.

“Hello, Mr. Blowfish how are you this morning?” said the damsel.

“Quite well, thanks. Though I was awakened by the most odd noise. Did you hear it earlier? It was a very shrill sound and when I poked my head out of my cave I saw a slew of bubbles of some very oddly shaped… seals, perhaps? hovering over some coral. Any idea what that was?” replied he.

“I can tell you, Sir,” I interrupted. “Those were my friends whom you saw. They are human scientists, not seals. The sounds were from the drill they were using to core the coral so that they could study how natural climate changes have affected coral health,” I continued.

“Fascinating!” exclaimed the Blowfish and the Damselfish, “It has been getting mighty hot around here these days,” they added in agreement.

After a few more minutes of dialogue, my tour guide came to fetch me to return to the surface. I said goodbye to my new friends, while they insisted I come again some day. Back on the boat I ran around excitedly telling the rest of the crew about my new found friends and ocean adventure. It was one for the books (or at least the blogs).  

- Hanny Rivera



Wednesday, December 18, 2013

Running with the Wind

Sea Dragon sails wing-on-wing: the mainsail is
on the left and the staysail is on the right. Photo by
Alice Alpert
Heave to. Raise the main. Ease the jib. Tack! Like our scientific vocabulary, sailing terms can seem like a foreign language, but on Sea Dragon we use them all the time.  

Sea Dragon is a cutter-rigged sloop--a bit of a tongue twister, but here's what it means. There are three sails: the mainsail extends back from the mast, the staysail is forward of the mast supported by a stay line, and in the very front is the jib. We adjust the size and angle of these three sails in order to catch the wind in just the right way.

Size is simple. We want to use as much sail area as possible without "overpowering" the boat, which makes it difficult to steer and increases our chances of ripping a sail. If the wind is strong we can reef the mainsail--roll up the bottom of the sail and lower the head to decrease the area we present to the wind. Changing the angle between the sails and the boat is called "trimming." Given the direction we are sailing, the air should flow past both sides of the sails smoothly. Small pieces of fabric called telltales show us how the air is moving across each face of our sails. We use ropes called "sheets" to trim the sails until the telltales are lying flat against the sails and not flapping.

In general there are two kinds of sailing: downwind and upwind. Sailing downwind is simple, we just present as much sail area as possible and allow the wind to push the boat forward through the water. Going straight downwind, we put the mainsail out to one side and the staysail or jib out to the other. This is called "wing-on-wing."

We use lines and winches to trim the sails. Wraps around the winch
create friction to hold the line in place. Photo by Alice Alpert

But it's going upwind the Sea Dragon really has wings. The idea of moving forward using wind that is coming towards us is a little bit counter intuitive. In this case, "close hauled," the sails become airfoils like the wings of a plane, except that the wings are turned vertically. The wind rushing past the curved sails generates lift that propels the boat forward. We can't sail directly into the wind, but this technique works if the wind is more than 45 degrees off the direction we want to travel. To go straight into the wind we must tack: sail 45 degrees off the wind in one direction, then turn and sail 45 degrees from the wind in the other direction.

Going upwind, the wind pushes the sail over and the boat will lean or "heel" in one direction. We heeled strongly to port (left) on our passages to Martinique and Barbados and experienced life at 30 degrees, which was so exciting that it sometimes knocked us out of bed!

Looking up Sea Dragon's mast you can see the stays holding
the mast up. The mainsail is on the far left, the staysail in the
middle, and the jib on the far right. Photo by Alice Alpert
I love how sailing weaves human engineering together with the natural world. The boat is an amazing system of sails and lines and aerodynamic shapes and hand operated winches and pulleys that uses air currents to move along.

But while we take advantage of the wind, we are also completely at its mercy. There is a constant give and take, and the sailor is at the center of it all.

Now on our passage to Curacao we are "running with the wind," traveling almost directly in the same direction as the wind. On night watch with a full moon, the constantly moving surface of the dark water reflects the moonlight like liquid obsidian. The sails stretch out like wings and Sea Dragon seems to glide along. Standing at the helm of this powerful boat driven by the far more powerful wind is amazing at any time, but tonight it feels magical.

-Alice Alpert

Monday, December 16, 2013

Teamwork

Three islands down, one to go, and Sea Dragon is well stocked with coral samples. All signs are pointing to a successful expedition. But most of the success should be attributed to the friends who helped us along the way.

Coral skeleton cores drilled in Barbados are packed away.
Photo by Tom DeCarlo
Each time we arrive at an island to sample corals, there are two main tasks: locate large coral colonies, and then drill skeleton cores. After three islands, our system of drilling corals is well polished and maximized for efficiency. Two, 2-diver drill teams keep both drills spinning at all times while we are underwater. Each team consists of a driller and an assistant, who labels the core as it comes out, plugs the hole once the core is finished, and scouts the next colony to drill.

The tricky part of our drilling system is to keep up a steady supply of compressed air to power our drills. This is where the crew of Sea Dragon shines. One dinghy (a small inflatable boat) anchors above the divers of the drilling teams, while a second dinghy shuttles air tanks back and forth between the first dinghy and SeaDragon, which is anchored narby and has a compressor to fill tanks.

When a tank runs out of air underwater it becomes buoyant enough to float. The drilling teams let go of the tank and it floats to the surface. The whole operation relies on the crew at the surface having a full air tank ready to go. When an empty tank surfaces, the dinghy crew drops a full tank down to the bottom (all the compressed air in the tank makes it heavy enough to sink.

For our drilling system to be useful, however, we need to know where to find large coral colonies. Islands in the Caribbean may be small, but fully exploring even a modest island 15 to 45 miles long to find the largest corals could take months or years. That's where local knowledge saves the day for us. Luckily for us we have collaborators everywhere along our route who point us in the right direction, telling us exactly where to go to find the largest corals. On our own, we be completely lost.

Three islands into the expedition, it is obvious that we are only a fraction of the whole operation. We owe huge thanks to Dr. Tyler Smith of the University of the Virgin Islands; Ewan Tregarot and Jean-Phillippe Marechal of the Marine Observatory of Martinique; Angelique Brathwaite, Richard Suckoo, and Caroline Bissada-Gooding of the Coastal Unit of the government of Barbados; Dr. Mark Vermeij of Research Station Carmabi in Curacao; and of course the awesome crew of SeaDragon.

Sea Dragon crew member Mitch shuttles a SCUBA
tank in the dinghy. Photo by Tom DeCarlo.
The importance of our collaborators really hit home during our first day in Martinique. Just arrived to a totally new place where none of our team has ever been and no idea where to find the largest corals, and the belt of the compressor on Sea

Dragon broke. No compressor means we can't fill our air tanks, which means no SCUBA diving and no coral sampling. Things were not looking good. In a matter of a hours, though Ewan and Jean-Phillippe went ashore and found a replacement belt to fix the compressor and showed us to a beautiful reef full of huge coral colonies. From a morning that seemed to be a disaster, we were right back in full swing by the afternoon doing what we came here to do: drill corals.

-Tom DeCarlo

Thursday, December 12, 2013

How to stop an invasion? Eat it.

In 2005, they were a rare sight, a novelty, something to get excited about. In 2010, they became an invasion. Today, there's no end in sight.

The lionfish: Beautiful. Destructive. Tasty?
Photo courtesy of NOAA
The lionfish is an invasive species originally from the Indo-Pacific that is making its mark on the Caribbean. They are beautifully striped and adorned with a feathery 'mane,' but lionfish have a dark side in the shape of venomous spines and a voracious appetite for reef fish. Lionfish are also fierce predators, yet they have no natural predator in the Caribbean.

The story goes that a few lionfish were released into the ocean, perhaps accidentally, from aquaria around South Florida. For a few years, they were spotted along the Florida and Atlantic Coasts. Then Bermuda, then a few Caribbean islands. Then their population exploded and are now found everywhere in the Caribbean.

We're not talking about just a few lionfish here and there on Caribbean reefs. We were told that divers in Martinique recently speared over 200 lionfish, that's around 100 pounds, in half an hour.

Despite efforts to control their numbers, they keep coming back. And we still do not understand much about how lionfish populations spread. Some larvae may disperse with ocean currents. Many islands have lionfish populations living hundreds of feet deep that may come up and repopulate the shallow reefs.

The lionfish invasion is almost certainly too large and too widespread for marine parks and local governments to eradicate them. One of the most promising ideas for how to control lionfish numbers is to establish a commercial fishery for lionfish. There are certainly many more fishermen in the Caribbean than there are scientists or marine park managers. Lionfish, however, have not yet become popular enough in restaurants and in homes to drive demand. Perhaps part of the reason is that it's an unfamiliar fish and people are not sure how to prepare it.

Carefully remove venomous spines before preparing.
Photo by Alice Alpert
Between drilling coral samples on Martinique we speared nine lionfish. Here's one sure way to prepare a delicious lionfish meal.

Lionfish ceviche
Chopped lionfish fillets in juice of lemons, limes, and oranges
Fresh chopped red peppers, onion, and tomato
Salt, pepper, and fresh cilantro to taste

Delicious! And helping to protect Caribbean reefs.

-Tom DeCarlo

Wednesday, December 11, 2013

Riding the Dragon

The Caribbean wasn't supposed to be like this. This sea is known for being calm and pleasant, but that's not how I feel during my first watch on our transit from St. John to Martinique.

Sea Dragon crawls up what seem to be mountains of water and crashes down on the other side, filling the air with spray. The wind is blowing at a sustained 30 knots, with frequent squalls of up to 48 knots. At these speeds the wave tops blow off in smoky wisps. Spray shrouds the surface of the water and the visibility is no better than in a fog. Raindrops blown by the wind feel like they are burrowing into my skin. After each wave soaks the deck, the water trickling into my mouth is ferociously salty but gradually sweetens as the rainwater dilutes it. The mainsail is now triple reefed—folded much smaller than its full size so it can carry us through the strong winds without overpowering the boat.
Sea Dragon in calmer waters.
Photo courtesy of Pangaea Exploration

At times the helmsman wears goggles to see in the spray. I slither across the precipitous deck always keeping three points of contact. Huddled behind the wheel as the leader of my watch mans the helm, I'm not sure how much help I am. I remember that this boat can roll so that its mast is in the water and still right itself, and I understand what my watch leader meant when he said that the boat is able to sail much harder than the crew are willing to endure.

My 4-8:00 a.m. watch feels interminable and my fingertips begin to resemble brain corals somewhere in the early morning, but then the sun rises, not that I can see it through the thick clouds. Even so, the light brightens my mood and although there are still two hours in my watch, I know I will be fine.

We are on the first transit of the expedition, a 300-mile voyage and are sailing heeled over 30 degrees on a port-tack into the wind. Life at an angle is a new experience—you must plan each step and maneuver, timing it with the irregular pitch of the boat and making sure you are sufficiently braced. When it's my turn to cook dinner, I abandon my grand plans of baking bread and making a cabbage salad and instead opt for chili. Opening cans of vegetables is much easier. Still, the stove poses some challenges. It swings freely so pots are always upright, but that means the knobs are moving targets. I finally get it adjusted right and the chili tastes quite good, although no one has much of an appetite.

The next two days are a blur of wet people moving around a boat that has become muggy, damp, slimy, and salty. No one talks much. There isn't much to do but endure the watches and lie in your bunk. I read a bit, but bringing out a computer, let alone washing the salt off of my body, is completely out of the question.

Eventually I do adjust to this new way of life, and I am steering the boat when the steep, otherworldly silhouette of Martinique appears, signaling the end of our crossing.

-Alice Alpert

Sunday, December 8, 2013

A Day in the Life of a Scientist

A question like, "What do you do?" would be easily answered by most. But as a scientist it's often difficult to put into words all the things that one might "do" during a regular day, let alone a day in the field. So I'll take you on tour of our last few days aboard the Seadragon, to give you a better (and hopefully more interesting) story than the 10-second elevator speech you'd normally get.

As the sun streams through the porthole windows above our bunks, we awaken to the smell of breakfast being prepared in the galley (that's ship-speak for kitchen). We huddle around the saloon and begin to organize ourselves for the day's work as we eat. Checking weather conditions, we ensure that the plan we agreed upon the previous night can still be carried out.

Today, we're going to scope out one, hopefully two, new locations to see if we can find corals big enough to drill. We finish up our breakfast—some delicious scrambled eggs—and under clear skies and a lovely breeze, we quickly gather the necessary gear for the morning's trip: wetsuits, snorkel gear, dive gear, and, of course, our precious drills. Then we set off from the Seadragaon and head to Hans Lolik, a small Island near St. Thomas. Arriving on location, we jump right in, the four of us spread out in search of massive corals.

Below us lays a vast expanse of vibrant coral, sea fans, and, unfortunately, many dead coral. The Caribbean has suffered several widespread losses of corals over the last few decades. For instance, Acropora palamata, which used to be the major species in the Caribbean, was nearly driven to extinction by white-band disease, an infection that spread quickly through the entire region. During our dives we've seen the remains of many of these Acropora palmata colonies. Though they retain their characteristic shape they mostly look like weathered rocks, and are often covered in algae or, more promisingly, by tiny juvenile corals that have chosen the coral rubble as their new home.

After several minutes of swimming, I spot what we're looking for—a large colony of Diploria strigosa, commonly called brain coral due to its windy, rugged appearance and growth pattern. "Jackpot!" I yell out to my colleagues and the boat tender, who brings over our dinghy with supplies. We swap our snorkel for scuba tanks and begin to drill. While two of us work on getting the core, the other two continue scouting coral. Before, lunch we've successfully drilled two cores and are feeling pretty accomplished.

Tom and Pat deploying the "big gun" hydraulic drill.
Photo by Alice Alpert
We head back aboard Seadragon for a quick recharge, both of our scuba tanks and our growling stomachs, and prepare to head to the second new site of the day: Fish Bay, near St. John. Because this is a new site we again begin our exploration by snorkel to avoid unnecessary hassle with our gear until we're sure we need it. This time our search takes no time at all, as we're surrounded by gigantic boulders of coral.

Up to now we had been using our smaller pneumatic drills, which run off scuba tanks. These colonies merit a little more, so we're going to need our large hydraulic drill. We prepare the big guns and get positioned to drill our core. It all begins smoothly enough, our first near-meter-long piece comes out quickly and the second follows suit. The third proves more difficult, but with the day drawing to an end, we'll have to head back to our home-away-from-home and finish the job tomorrow.

Our ride back to Seadragon rewards us with a stunning sunset, and as we gather around the dinner table we again begin to plan our next day. Once that's done, the nighttime is reserved for stargazing and blog writing.

Tomorrow a whole new adventure awaits.

-Hanny Rivera

Thursday, December 5, 2013

Ready to Drill

We traded the drizzle of a dank December morning in Woods Hole for the tropical heat and humidity that blasted our faces as we stepped off the plane in St. Thomas, U.S. Virgin Islands. Team assembled, gear loaded on deck, fresh food stowed away, we are ready to get to work. Tomorrow (Thursday) begins the first day on SeaDragon, the 72-foot sailboat that we chartered for our expedition. Our first order of business is to search for large coral colonies on the south and north shores of St. Thomas. Once we locate suitable colonies, we will begin drilling cores of coral skeleton one meter or more in length.

Drilling equipment (yellow boxes) ready to be loaded
on SeaDragon. Photo by Tom deCarlo
SeaDragon has a draft of 11 feet, so it cannot go close to shore, where we expect to find large coral colonies. Instead, we will load up a small dinghy with drilling equipment and SCUBA divers. We will use two different types of underwater drills. Handheld pneumatic drills are powered by compressed air from a SCUBA cylinder. Our larger hydraulic drill is powered by oil pumped by an engine on the surface down through tubes to spin the drillbit. The pneumatic drills are easiest to use, and little assembly is required. Getting the hydraulic drill set up is not an easy task, but once going, it drills through corals in no time.

Finding corals to drill may prove to be our most difficult task. Few survive the centuries it takes to build meter-tall colonies. Bioeroders—organisms like some clams and sponges that dissolve coral skeleton to build their homes—excavate the base of the colony until it eventually topples over. Macroalgae can overgrow coral colonies. Sometimes warm ocean temperatures stress a coral and cause it to die. The corals that survive all this can be few and far between, but they are the ones we need to find.

Spirits are high as the preparations come to an end and the challenging, yet fun and exciting expedition is about to begin.

 -Tom deCarlo

Tuesday, December 3, 2013

Objective: Science

Coral reefs are sometimes called the rainforests of the ocean, full of whimsical creatures that fill specific and often surprising ecological niches. But, like rainforests, on land, coral reefs all over the world are under siege.

Picture a coral reef with colorful fish flit between coral knobs, hiding in the crevices of branching coral. A manta ray glides by, majestically flapping its wings. But in one corner, small patches of green seaweed called macroalgae are beginning to grow. They start out small, but soon cover the coral colonies, gradually cutting off their access to light. Eventually the once vibrant seascape resembles a bumpy lawn of fleshy macroalgae carpeting the strangled coral.
Healthy reef seascape in Palau with low
macroalgae growth. Photo by Hannah Barkley
Unfortunately this sad story is repeating itself around the world, especially in the Caribbean. On this expedition, we hope to collect samples that will help us investigate what may be causing the decline in coral reef health here. People often think of tropical seas as warm and delightful places to swim, but they are actually a very hard environment for marine organisms. Corals have adapted to the low nutrient levels found in the tropics by working together with their symbiotic algae to cycle nutrients efficiently and eke out every bit of energy from their surroundings.

In contrast, macroalgae usually have far more trouble growing in these conditions. However, if the environment becomes more hospitable for macroalgae they can outcompete the corals, gradually overrunning the coral reef. Macroalgae do play a role on the reef by providing food for herbivorous fish, so they aren’t all bad, but it’s important that all the inhabitants of the reef live in balance rather than one tipping the scales and taking over at the expense of the others.


It would be great if scientists could pinpoint one factor that favors macroalgae over corals. Unfortunately, it looks like there are a lot of factors, some of which are very difficult to address. Extra nutrients entering the reef through fertilizer runoff or human waste, as well as the decline of herbivorous fish can give macroalgae a leg up.


Reef in Taiwan with macroalgae overgrowing corals.
Photo by Tom DeCarlo
In the Caribbean, disease has also wiped out some of the faster-growing corals, and killed off sea urchins that eat macroalgae. Given this foothold, macroalgae can take advantage of additional opportunities, such as disease, nutrient input, or overfishing of their predators to grow unchecked. In addition, stresses like rising temperatures and ocean acidification make it harder for corals to keep themselves ahead of macroalgal growth.

Many of these processes are related to human activity, but there are also natural impacts on coral reef ecosystems. My team is interested in how natural climate swings can also affect reef health. On this expedition, we will collect as many corals as we can from many sites in the Caribbean to investigate coral health in the context of natural climate variability. Here we go!

-Alice Alpert

Thursday, November 28, 2013

All Hands on Deck


Seadragon prepares to leave port at Christmas Island. 
Photo: Chip Young
There is something familiar about the soft rocking of the plane as I curl up in my seat, on my way home for Thanksgiving. Then it hits me – Seadragon! Aboard, we slept in hammock bunks that rolled with the waves. This was one of my favorite things about being at sea – feeling the surge of the water lull me to sleep.

For three weeks this December, the 72’ sailing yacht Seadragon will once again be my home base as I journey with my Cohen lab mates through the Caribbean collecting coral cores. I was part of an expedition on this boat last year in the equatorial Pacific, and I know that we are in for a treat.


First mate Emily Penn peers out from the "bedroom"            
that slept all nine of us. Photo: Alice Alpert




Conducting scientific research from Seadragon is a unique experience for a number of reasons. Very few living oceanographers have done research from a sailing vessel. But for our work we only need a way to get from one island to another and a small dinghy to dive from. No complicated water sampling or profiling instruments for us. So Seadragon is perfect: energy efficient, able to travel to remote locations, and cost-effective. An added bonus is learning to sail – or at least to follow the captain’s directions.

On the previous expedition, when we were in transit we organized into three watches of three people each: 4 hours on, 8 hours off, all through the day and night. The watch members were responsible for navigating, cooking, keeping ropes tidy, and updating the ship’s log. After hours at the helm together we all knew each other very well.

Another feature of the boat is that it was originally built as a racing yacht, which means that it is very hydrodynamic, but not very spacious. We were each limited to a 20”x16”x10” plastic tub to hold all of our belongings, and we slept in hammocks stacked 3 tall. Packing our scientific gear was like a game of three-dimensional tetris.

The sun sinks into the Pacific, reflecting off of 
Seadragon's hull. Photo: Emily Penn
But the tight quarters were a small price to pay for diving in remote waters, collecting fabulous coral cores, and feeling the wind catch the sails. I’m ready for more!

--

Alice Alpert

--

Sunday, November 24, 2013

Resilient Corals


Pat drills into a coral colony on a previous expedition to Bermuda.
Photo: T. DeCarlo




Press the trigger. The drill screams, the bit whirls, air bubbles erupt. The pitch drops as the bit digs into the coral. Coral tissue spews, and the fish swoop in for a snack. It all happens quick as we begin drilling a core of coral skeleton.

As SCUBA divers, we are always so careful to not touch the coral. They are delicate organisms. An accidental kick with a fin can cause some real damage.

Yet, the corals always recover from our drilling. We drill into a relatively small area on the surface of the colony, careful not to damage the rest of the colony. A coral is made of many thousands of coral polyps, which together form a colony. Each polyp is a separate animal, which looks like a mouth with tentacles waving around searching the water for plankton to munch on. But all of the polyps in a colony are clones, genetically
identical.
Pat pulls a skeleton core from a colony. The core is white
because it is only the former skeleton, not the living tissue.
Only the very top of the core is living coral. Photo: A. Cohen    









Only the very outer surface – the width of your little finger or less – of a coral is living. Underneath this thin veneer of life, all that remains is the former coral skeleton. The polyps constantly build new skeleton on top of old, growing outward. The older skeleton becomes buried within the colony, left behind by polyps that have built the colony taller and taller.

After we remove our skeleton core, we fill the hole with a cement plug and secure it with nontoxic underwater epoxy. This serves two purposes. Plenty of reef creatures – like octopus, urchins, and some fish – would find that our drill holes make perfect homes. Our cement plugs not only keep these creatures out, but they also provide a surface for the coral to grow over.

Come back a few months later and the cement will be only partly visible. New coral polyps cover the outer edges. Give it a year, and the plug is invisible, buried beneath the living surface of the colony. 

A coral colony recovering from drilling. The cement plug
on the right was emplaced 6 months prior to the photo
and is partly grown over. The cement plug on the left
is freshly epoxied to the colony surface. Photo: A. Cohen
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Tom DeCarlo

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Saturday, November 23, 2013

Don't forget the packing tape

The key to any successful expedition is careful preparation. I have come to really appreciate that I can drive my car five minutes to the nearest hardware store and buy almost any tool I can imagine. Painting the deck and forgot to buy a paint stirrer? What a waste of fifteen minutes.

Some of our drilling supplies. Photo: T. DeCarlo
But on the ocean, if we forget something we are either out of luck or we can spend a day docking at the closest island only to find whatever we need does not exist on the island.

The most difficult part of preparation is realizing all the items we need to get us, our gear, and our samples home. Of course, the packing list starts with the obvious items for our work: underwater drill, check. SCUBA gear, check. Cement plugs and epoxy to patch up the coral colonies that we drill, check. GPS, check. Camera, check. Ok, our purpose is to collect coral skeleton cores, and we have everything we need to do that. That's the natural thought process.

But, oh how awful it would be to collect our beautiful skeleton cores, place them carefully into a box, and realize we have no way to seal the box. Packing tape, check.

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Tom DeCarlo

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