Paleo Slide Set: Coral Paleoclimatology
Extracting core with hydraulic drill on a Porites lobata colony, Clipperton Atoll

While drilling does kill the few polyps living on the core surface, the process 
does not damage the colony as a whole. In fact, polyps often grow over the holes 
left by drilling within a couple of years. As we discussed earlier, only the surface 
of a colony is alive; all of the rest is the calcium carbonate skeleton deposited 
by the polyps. This skeleton is created from the calcium, carbon, and oxygen 
available to the coral in the water and organisms that surround it. When a polyp 
lifts itself and encapsulates a piece of skeleton, the chemistry of that portion 
of skeleton is locked in forever. In other words, every time a piece of skeleton 
is created, it leaves an indelible record of the conditions under which it was created. 
It is this record that paleoclimatologists are trying to unlock by drilling 
long cores into the coral skeleton.

Photo Credits:
Maris Kazmers
SharkSong Photography, Okemos, Michigan