As they get larger, corals grow in a tree-like fashion, forming growth rings. In contrast, Roark used radiocarbon dating in his 2006 study to look at the amounts of the isotope carbon-14 in the corals.
C decays to nitrogen with a half-life of 5,730 years.
Just like tree rings say a lot about growing seasons over time, annual growth increments in the shells can tell researchers a lot about ocean conditions over time.
Wanamaker, now an Iowa State University associate professor of geological and atmospheric sciences, started building the marine archive by processing all those clams - painstaking lab work that involved sectioning shells, embedding shell slices in epoxy blocks, measuring down to a millionth of a meter, drilling samples, radiocarbon dating and determining oxygen isotopes.
What would happen if a dinosaur bone were carbon dated?
But some researchers questioned Roark's methods, arguing that carbon in the food the corals were eating from the ocean floor and incorporating into their skeletons could be older than the corals themselves — giving rise to unduly ancient age estimates. Doesn't carbon dating or potassium argon dating prove the Earth is millions of years old? var Folder=Creation Evolution&var Page=Carbon Aitken, M. Scientists use a technique called radiometric dating to estimate the ages of rocks, fossils, and the earth.Some species of coral can live for over 4,000 years — longer than any other animal that lives in the ocean, a study has found.Uncertainty over how to date coral makes estimates of their lifespan contentious.