Thursday, May 17, 2012

And we drilled (drum roll, please)... 3 inches!

We awoke to a beautiful day here at our new home, Dive Kiribas, a collection of 5 thatched huts complete with our own private beach. The best part about our accommodations is the shower, which is made out of fossil corals (see photo).

The day’s agenda was ambitious. We had to touch base with the Christmas Island conservation officials early in the morning, test our drill during a test dive, and snorkel across reefs in the afternoon searching for healthy medium-sized coral colonies to drill. The officials were incredibly amenable to our plans, and surprisingly unconcerned about the drilling we would do in the next days. They instead were keen to monitor our movements in the more remote parts of the island, where nesting seabirds can be disturbed. Of course, to ensure the preservation of the colonies we drill, we will plug each drill hole with a cement plug that the coral will grow around and eventually seal up over several years.

Testing the coral drill on shore
Turning our attention to the test drill, we quickly realized that the new pneumatic (air-powered) coral drill was significantly less powerful than the hydraulic coral drill that I have used on all my previous expeditions. We wondered whether it would cut a pristine modern coral colony more easily than the hardened rubble we tested on our beach (see photo). Our objective is to drill 5-6 cores of 24" each during the trip. We already have a couple of very long cores that end in the 1990’s, so we need to get back to the 1980’s to splice into these longer cores. Christmas corals grow just under 1" per year, so if we need 25+ years of core we’ll have to drill 24" or so of core. A paultry goal by coral paleoclimatology standards (we typically target heads that are >6’ tall), but we this time our goal is to assess the reproducibility of overlapping coral cores in the very recent past, when plentiful instrumental climate records exist, rather than extend back many decades with a single core, as is common practice.

Kim & Diane showing off their day's coral haul
Having identified a suitable test specimen in 20’ of water, Diane Thompson and I descended to begin our first drill attempt. It was short and not very sweet – we blew through the two SCUBA tanks we had brought in under 10 minutes of drilling, with only 3" of core to show for our efforts! (see photo) Keep in mind that we could easily drill 12" of core in 10 minutes with the trusty hydraulic rig. We were crushed. How would we ever get the 24" of core that we needed, let alone 5-6 different cores? We limped back to base determined to fix what was surely a gaping leak in the air lines. And we leak-tested, swapped parts, scratched our heads, and ultimately came to the conclusion that we would need A LOT of air tanks to drill a single core. A quick e-mail to my past student Intan Suci-Nurhati, who has definitely surpassed her mentor in meters of coral drilled with a pneumatic drill, confirmed our suspicions. We’d need 10+ tanks to achieve our target core length, hopefully over the course of a single 45-minute dive. We spent most of the rest of the day dreaming up a rope-pulley system designed to get 10 tanks down to 30’ and back up at 5-minute intervals. We will "brute-force" it this time, and cross our fingers for cooperative weather and a smooth tank-shuttling operation by our trusty team. We’ll be very lucky to get 1-2 useable cores in 1-2 dives tomorrow. Boy do I miss my hydraulic rig, sitting in 4 crates back in Atlanta. Of course the grass is always greener – I no doubt would be cursing the cumbersome, heavy, loud, smelly engine if it were here instead.

Oh, and number of shark sightings today: 0. Very sad but predictable. Tomorrow we’ll be farther from the island’s various villages, so I remain hopeful that we’ll see signs of a healthy, vibrant reef ecosystem on a different part of the island.
Out for an end-of-day snorkel (and water sample). From left:  Kim Cobb, Hussein Sayani,
Jess Conroy, Liz Wiggins, and Diane Thompson
Quote of the day: "If I were to throw up, where would be the best place for me to do that?" [Liz Wiggins, on getting back onto land after a long boat ride. She found her land legs after a few minutes. Funny, most people don’t realize that it’s often the getting-back-on-land part that can put you over the edge.]