The Oyster Time Machine

A cross section of an oyster reef is similar to rock layers in the Grand Canyon – different layers represent different periods in time. 

OYSTER SHELLS at the surface of the reef were most recently alive, while more deeply buried oyster shells are increasingly older. Some oyster reefs have existed for several hundred years, meaning shells beneath the surface of the reef could be decades old and the deepest shells can even be centuries old! Samples from the deeper layers act as a baseline for what the environment was like in the past. Knowledge of a baseline helps determine how much oyster populations have changed over time. 

Hover over the images in the following infographic to learn more!