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
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

Tom DeCarlo


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.


Tom DeCarlo