Geochemistry of Slow-Growing Corals: Reconstructing Sea Surface Temperature, Salinity and the North Atlantic Oscillation

A 225-year old coral from the south-shore of Bermuda (64CW, 32CN) provides a record of decadal-to-centennial scale climate variability. The high accretion rates, longevity, and skeletal growth bands found in coral skeletons make them an ideal resource for well-dated, seasonal climate reconstructions...

Full description

Bibliographic Details
Main Author: Goodkin, Nathalie F.
Other Authors: WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
Format: Text
Language:English
Published: 2007
Subjects:
Physical Chemistry
Hydrology
Limnology and Potamology
Mechanics
*GROWTH(GENERAL)
*CLIMATE
*OSCILLATION
*SALINITY
*SEA WATER
*CORAL
*SURFACE TEMPERATURE
BANDS(STRIPS)
CALCIUM
POSITION(LOCATION)
BERMUDA
SKELETON
STRONTIUM
NORTH ATLANTIC OCEAN
MEAN
ACCUMULATION
RECORDS
RESOURCES
SEASONAL VARIATIONS
HIGH RATE
OCEAN SURFACE
North Atlantic
North Atlantic oscillation
Online Access:http://www.dtic.mil/docs/citations/ADA472632
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA472632
Description
Summary:A 225-year old coral from the south-shore of Bermuda (64CW, 32CN) provides a record of decadal-to-centennial scale climate variability. The high accretion rates, longevity, and skeletal growth bands found in coral skeletons make them an ideal resource for well-dated, seasonal climate reconstructions. Coral skeletons incorporate strontium (Sr) and calcium (Ca) in relative proportions inversely to the sea surface temperature (SST) in which the skeleton is secreted. Delta(exp 18)O of the coral skeleton changes based on both temperature and the 8(exp 18)O of sea water (DeltaOw), and 80 is proportional to sea surface salinity (SSS). Sr/Ca was used to reconstruct winter-time and mean-annual SST, employing the first growth-corrected Sr/Ca-SST model. SSTs are l.5C colder during the end of the Little Ice Age than today. SSS is fresher during that time. Winter-time SSTs at Bermuda are correlated to phases of the North Atlantic Oscillation (NAO). Using winter Sr/Ca as a proxy for temperature, we show strong coherence to the NAO at multi-decadal and inter-annual frequencies. These coral records show changes in variance in the NAO during the late 20th century, but limited changes in the mean phase of the NAO, implying that climate change may be pushing the NAO to extremes but not to a new mean position. The original document contains color images. All DTIC reproductions will be in black and white.

Similar Items