Tree rings give us useful information about the past rainfall in an area. But did you know that sea coral also displays unique growth rings? Some corals can live up to 5,000 years, making them the longest living animals on earth. Like trees, their growth is influenced by the environment. Studying coral layers can give us clues about past ocean conditions. Notice the similarities in the tree rings and coral rings shown below (image 1).
In 1997 a scientist named Brad Linsley traveled to an island in the South Pacific called Rarotonga. He carefully removed a long shaft (called a core) from a coral reef. Below you will find a map (image 2) showing the location of Rarotonga and a picture (image 3) showing the shape and size of coral cores. Dr. Linsley used only one core for his analysis.
