Friday, April 15, 2005

452: Open-System Coral Ages Reveal Persistent Suborbital Sea-Level Cycles -- Thompson and Goldstein 308 (5720): 401 -- Science

Open-System Coral Ages Reveal Persistent Suborbital Sea-Level Cycles -- Thompson and Goldstein 308 (5720): 401 -- Science:

Sea level is a sensitive index of global climate that has been linked to Earth's orbital variations, with a minimum periodicity of about 21,000 years. Although there is ample evidence for climate oscillations that are too frequent to be explained by orbital forcing, suborbital-frequency sea-level change has been difficult to resolve, primarily because of problems with uranium/thorium coral dating. Here we use a new approach that corrects coral ages for the frequently observed open-system behavior of uranium-series nuclides, substantially improving the resolution of sea-level reconstruction. This curve reveals persistent sea-level oscillations that are too frequent to be explained exclusively by orbital forcing.
This research relies on understanding the evolution of the corals, and it reveals important information about forces driving the evolution of life.