Skip Navigation
USGS - science for a changing world

Woods Hole Coastal and Marine Science Center

Skip Navigation

Summary Information for Field Activity 2005-001-FA

Area of Operations: St. George Sound, eastern Apalachicola Bay National Estuarine Research Reserve, Apalachicola Bay, Florida, United States, Gulf of Mexico, North America, North Atlantic

Dates: March 17, 2005 to April 14, 2005

Chief scientist: Dave Twichell

   Linda Rowe, NOAA

Objectives: Map the sea floor and shallow stratigraphy of Apalachicola Bay using sidescan sonar, bathymetry and high-resolution seismic to determine the controls on the distribution of oyster beds.

Type of Activity: Seismic profiling; Sea floor mapping;Sea floor mapping

Information to be derived:

Summary: This first year of a two-year program to map the floor of Apalachicola Bay focused on the eastern part of the Apalachicola Bay National Estuarine Research Reserve known as St. George Sound. Weather had a major impact on the amount of data collected during this field program. Because of the shallow depth of the bay (average depth 3 m), the sidescan sonar had to be towed close to the sea surface. When the wind exceeded approximately 15 kts the surface noise degraded the sidescan sonar imagery below an acceptable quality. The only areas not mapped were the crests of the oyster bars where water was less than 2 m deep, and a narrow band in the central part of the bay that could not be completed due to weather conditions. Sidescan sonar imagery, Submetrix bathymetry, and chirp sub-bottom profiles were collected simultaneously and were navigated using RTK DGPS. Tracklines were spaced 75-100 m apart and allowed complete sidescan sonar coverage, while the line spacing was such that, in these water depths, the interferometric bathymetry imaged 30-50% of the sea floor. Some parts of the floor of the bay were covered by muddy gas-charged sediment, and in these areas the sub-bottom penetration was minimal.

Contact: Brian Andrews (

InfoBank: uses the identifier R-1-05-FL. Visit this site for more information.

Related Links:

Platform Info:

Publications resulting from these data

Twichell, D.C., Andrews, B.D., Edmiston, H.L., and Stevenson, W.R.,2007, Geophysical mapping of oyster habitats in a shallow estuary; Apalachicola Bay, Florida: U.S. Geological Survey Open-File Report 2006-1381. (Also available at

Twichell, D.C., Pendleton, E.A., Poore, R.Z., Osterman, L.E., and Kelso, K.W.,2009, Vibracore, radiocarbon, microfossil, and grain-size data from Apalachicola Bay, Florida: U.S. Geological Survey Open-File Report 2009-1031. (Also available at

Twichell, D., Edmiston, L., Andrews, B., Stevenson, W., Donoghue, J., Poore, R., and Osterman, L.,2010, Geologic controls on the recent evolution of oyster reefs in Apalachicola Bay and St. George Sound, Florida: Estuarine, Coastal and Shelf Science, v. 88, no. 3:385-394p.: p. 385-394. (Also available at

Osterman, Lisa E., Twichell, David C., and Poore, Richard Z.,2009, Holocene evolution of Apalachicola Bay, Florida: Geo-Marine Letters, v. 29, no. 6: p. 395-404. (Also available at

Cross, V.A., Twichell, D.C., Foster, D.S., and O'Brien, T.F.,2012, Apalachicola Bay Interpreted Seismic Horizons and Updated IRIS Chirp Seismic-Reflection Data: U.S. Geological Survey Open-File Report 2012-1003. (Also available at

Data Types and Locations:


Deck photos of field activity operations



Skip USGS links group

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USAGov logo U.S. Department of the Interior | U.S. Geological Survey
End of USGS links group
Page Contact Information: WHSC Webmaster
Script last modified Wednesday, 17th December, 2014 @ 10:53am