CHRONOLOGICAL PERSISTENCE OF ACROPORA CERVICORNIS AT CORAL GARDENS, BELIZE

WAGGONER, Tanner, Washington and Lee University Geology Department, Washington and Lee University, 204 West Washington Street, Lexington, VA 24450, GREER, Lisa, Department of Geology, Washington and Lee University, Lexington, VA 24450, GUILDERSON, Thomas P., Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, P.O. Box 808, L397, LIvermore, CA 94550, CLARK, Tara, Radiogenic Isotope Facility, University of Queensland, Radiogenic Isotope Facility, University of Queensland, Bisbane QLD, 4072, Australia, BUSCH, James, Department of Geology, Washington and Lee University, 104 N Randolph St, Lexington, VA 24450, BIEGEL, Jenna, Department of Geology, Washington and Lee University, Lexington, 204 West Washington Street, Washington and Lee University, Lexington, VA 24450, LUSTIG III, Harry, Department of Geology, Washington and Lee University, Lexington, 204 West Washington Street, Lexington, VA 24450, CURRAN, H. Allen, Department of Geosciences, Smith College, Northampton, MA 01063, LESCINSKY, Halard L., Department of Life and Earth Sciences, Otterbein College, Westerville, OH 43081 and WIRTH, Karl, Geology Department, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105, waggonert16@mail.wlu.edu

Acropora cervicornis (staghorn coral) is an important framework-building scleractinian coral that dominated many Caribbean reefs throughout the Pleistocene and Holocene. Acropora spp. suffered collapse throughout the Caribbean since the 1980s as a result of white band disease and other stressors. Despite widespread decline, large populations of Acropora spp. are currently thriving at Coral Gardens Reef, Belize, south of Ambergris Caye where live coral cover is as high as 50% in some areas. This project aims to discern whether these populations were established after the Caribbean acroporid collapse or whether they are remnant populations from before the 1980s. To determine the timing of Acropora spp. dominance at Coral Gardens, pristine aragonite material was sampled from dead coral skeletons excavated from stratigraphic ‘pits’ in the coral death assemblage at two underwater sites. Stratigraphic Section One extended approximately 1.2 meters beneath the surface of the reef and Stratigraphic Section Two extended approximately 2 meters. Seventeen and 12 aragonite samples were extracted from Sections One and Two respectively, and aged using conventional radiocarbon dating techniques. Radiocarbon results from both sites indicate that A. cervicornis growth was initiated prior to the well-documented spike in atmospheric radiocarbon caused by nuclear weapons testing (late 1950s) and persisted throughout the mid-1960s. However, due to the lack of high resolution post-bomb radiocarbon calibration data for marine reservoir effects near Belize, additional dating techniques were needed to resolve the age of the more recent A. cervicornis corals. We obtained very precise ages utilizing U-Th dating to better constrain the chronological persistence of A. cervicornis at Coral Gardens. The ²³⁰Th age data suggest that some of the A. cervicornis colonies in Coral Gardens survived the wide-spread 1980s Caribbean acroporid coral collapse and that corals from beneath the living A. cervicornis canopy are synchronous with those taken from the surface of Stratigraphic Section Two. The results suggest some degree of continuity in reef growth at this site amidst greater Caribbean collapse of Acropora spp.

Session No. 252

T160. Topics in Paleoecology: Modern Analogues and Ancient Systems III

Tuesday, 3 November 2015: 1:30 PM-5:30 PM

Room 315 (Baltimore Convention Center)

Geological Society of America Abstracts with Programs. Vol. 47, No. 7, p.642

© Copyright 2015 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.

Back to: T160. Topics in Paleoecology: Modern Analogues and Ancient Systems III

<< Previous Abstract | Next Abstract >>

2015 GSA Annual Meeting in Baltimore, Maryland, USA (1-4 November 2015)

CHRONOLOGICAL PERSISTENCE OF ACROPORA CERVICORNIS AT CORAL GARDENS, BELIZE