A 240-Year Stable Oxygen and Carbon Isotopic Record in a Coral from South Florida: Implications for the Prediction of Precipitation in Southern Florida

Authors

Peter Koenraad Swart, University of Miami
Richard E. Dodge, Nova Southeastern UniversityFollow
Harold J. Hudson, National Oceanic and Atmospheric Administration

Document Type

Article

Publication Date

1996

Publication Title

PALAIOS

Keywords

Coral reefs, Corals, Montastraea faveolata, Florida

ISSN

0883-1351

Volume

11

First Page

362

Last Page

375

Abstract

This study reports on the δ¹⁸O and δ¹³C composition of the skeleton from a 240-year-old specimen of Montastraea faveolata growing in Biscayne National Park, South Florida. Annual variations in the δ¹⁸O of the skeleton deposited during the summer months show a bimodal correlation with summer rainfall. During wetter years, the δ¹⁸O of the coral skeleton and the amount of precipitation during the summer months are inversely correlated (r = -0. 7) reflecting dilution of the seawater by meteoric water lower in δ¹⁸O. During years in which summer rainfall is less than normal, increases in precipitation are positively correlated with skeletal δ¹⁸O (r = +0.6) reflecting the input of freshwater from the Everglades higher in δ¹⁸O. Based on this correlation the δ¹⁸O record of the coral skeleton suggests that the 19th and 18th centuries have been relatively dry compared to the 20th century. Carbon isotopic compositions of the skeleton are positively correlated with δ¹⁸O with the minimum in δ¹³C occurring several months after the minimum in δ¹⁸O. Since the mid 1930s there has been a decrease in δ¹³C of the skeleton. Explanations for this trend may be (1) it reflects the increased input of carbon derived from the destruction of terrestrial ecosystems, (2) its part of a long-term decrease in δ¹³C associated with increased addition of fossil fuel-derived CO₂.

Comments

©1996, SEPM

Additional Comments

NSF grant #s: OCE-8900005, OCE-8907101

NSUWorks Citation

Peter Koenraad Swart, Richard E. Dodge, and Harold J. Hudson. 1996. A 240-Year Stable Oxygen and Carbon Isotopic Record in a Coral from South Florida: Implications for the Prediction of Precipitation in Southern Florida .PALAIOS : 362 -375. https://nsuworks.nova.edu/occ_facarticles/77.