St. Petersburg Coastal and Marine Science Center
Corals deposit a skeleton of calcium carbonate. Variations in the coral skeletons are very useful for reconstructing past environmental conditions. Corals are long lived (100-300 years) and their skeletons have alternating light and dark layers that are caused by seasonal changes in growth rates. The couplets of light and dark layers represent annual bands, similar to tree rings, that can be used to determine the age of the coral skeleton. Variations in the chemical composition of the skeleton record environmental conditions such as seawater temperature, salinity, and pH as the coral grows.
We are analyzing coral skeletons to document past environmental changes and determine the relationships between the changing environment and coral growth. This information is critical to our understanding of the natural history of corals and will provide clues to the future of reef accretion processes and climate change.
During 2009 and 2010 we are analyzing corals recovered from the Dry Tortugas at the tip of the Florida Keys. The records will cover the last 200 to 250 years.
 Diver drilling into large coral head. [larger version] |
 Diver extruding sample (core) drilled from coral head. [larger version] |
 Cores drilled from corals drying on table. Samples from the coral cores are analyzed to provide information on coral growth rates and variations in ocean temperature and salinity over time. [larger version] |
U.S. Department of the Interior |
U.S. Geological Survey
URL: http://coastal.er.usgs.gov/crest/research-themes/climate.html
Page Contact Information: Feedback
Page Last Modified: May 06, 2013 @ 09:24 AM (JSS)
