Geologic controls on the recent evolution of oyster reefs in Apalachicola Bay and St. George Sound, Florida

Estuarine, Coastal and Shelf Science
By: , and 

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Abstract

Apalachicola Bay and St. George Sound contain the largest oyster fishery in Florida, and the growth and distribution of the numerous oyster reefs here are the combined product of modern estuarine conditions in the bay and its late Holocene evolution. Sidescan-sonar imagery, bathymetry, high-resolution seismic profiles, and sediment cores show that oyster beds occupy the crests of a series of shoals that range from 1 to 7 km in length, trend roughly north-south perpendicular to the long axes of the bay and sound, and are asymmetrical with steeper sides facing to the west. Surface sediment samples show that the oyster beds consist of shelly sand, while much of the remainder of the bay floor is covered by mud delivered by the Apalachicola River. The present oyster reefs rest on sandy delta systems that advanced southward across the region between 6400 and 4400 yr BP when sea level was 4–6 m lower than present. Oysters started to colonize the region around 5100 yr BP and became extensive by 1200 and 2400 yr BP. Since 1200 yr BP, their aerial extent has decreased due to burial of the edges of the reefs by the prodelta mud that continues to be supplied by the Apalachicola River. Oyster reefs that are still active are narrower than the original beds, have grown vertically, and become asymmetrical in cross-section. Their internal bedding indicates they have migrated westward, suggesting a net westerly transport of sediment in the bay.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Geologic controls on the recent evolution of oyster reefs in Apalachicola Bay and St. George Sound, Florida
Series title Estuarine, Coastal and Shelf Science
DOI 10.1016/j.ecss.2010.04.019
Volume 88
Issue 3
Year Published 2010
Language English
Publisher Elsevier
Publisher location New York, NY
Contributing office(s) Woods Hole Coastal and Marine Science Center
Description 10 p.
First page 385
Last page 394
Country United States
State Florida
Other Geospatial Apalachicola Bay, St. George Sound