Title

Geochemical Analyses From Florida’s ‘monster Coral’: Reconstructing Environmental Changes From The Port Everglades Area Over The Last 100 Years

Event Name/Location

11th International Coral Reef Symposium: Ft Lauderdale, FL

Document Type

Conference Proceeding

Publication Date

2008

Keywords

Coral Reefs, Florida, Environmental Monitoring

Abstract

In 2005, a 300+ year old colony of the star coral, Montastraea faveolata, was cored in 20 feet of water approximately 2 miles south of Port Everglades, Florida USA. Given the coral’s latitude and proximity to the activity and impact of a large urban population and a large shipping and cruise port, it is considered exceptional for both its age and size. The specimen therefore may provide insight into the effects of South Florida’s development on corals over time. Stable isotopic analysis of this coral’s skeleton reveals δ18O values between -4.1 and -2.6‰, and δ13C values between -3.5 and +0.4‰. Both the oxygen and carbon isotopes demonstrate regular seasonal cyclicity. Minor element concentrations were also measured. Ratios of Sr/Ca, Mg/Ca, and Ba/Ca vary between ~9.1 and 9.6 mM/M, 5 and 13 mM/M, and 4.5 to 6.5 mM/M respectively, and depict annual fluctuations in concentration. X-radiography of slabs from this coral’s skeleton reveals a 300 year chronology of seasonal density banding along with a period of anomalously high density from 1940 to 1970 which suggest that some sort of stress was acting on the coral. Re-evaluating the geochemical data in light of this density anomaly reveals, with few exceptions, little difference between the typical modern growth and the relatively high density period between 1940 and 1970. The exception to this is in the amplitude of stable isotopic variation, which does appear to be slightly suppressed where density was anomalously high in the coral with δ18O from -3.8 and -2.6‰ and δ13C between -2.5 and +0.4‰.

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