Spotlight on research diving: Aucilla River Prehistory Project

By Joseph Latvis, Project Operations Manager

The earliest Paleoindian explorers to enter the New World over 12,000 years ago exploited their Ice Age environment, particularly the menagerie of exotic animals they found here in such apparent abundance. Yet by 10,000 bp undeniable climatic changes had occurred, sea level had risen dramatically and the terminal Pleistocene extinction had taken its irrevocable toll on the great herds.

Since its inaugural year in 1983 the Aucilla (aw-sil'-uh) River Prehistory Project (ARPP) has annually conducted underwater research into the archaeological, paleontological and paleoenvironmental aspects of the Pleistocene/Holocene transition in Florida. Sponsored by the Florida Museum of Natural History, the ARPP in 1995 continued its exploration of one of the New World's richest, best preserved records of this important era.

The venue for this research is the Aucilla River drainage basin, located in the Gulf (of Mexico) coastal lowlands of Florida's Big Bend area, 45 miles southeast of Tallahassee. Under the direction of University of Florida co-chief scientists Dr. S. David Webb and Dr. Jerald T. Milanich submerged sediment banks 24 feet thick continue to yield a wealth of information in exquisite detail. The infinitesimal incremental rates of sediment deposition (grossly averaging 1 mm per year) include items as fragile as intact grape tendrils and gourd seeds 30,000 years old. The state of anaerobic preservation of such botanical materials enables radiocarbon dating techniques to firmly fix the timeline.

Underwater excavation is accomplished using traditional terrestrial troweling techniques, illuminated by a surface-powered 1,000-watt Snooper light to penetrate the tannic stained darkness at 30-foot water depths. A hydraulic dredge is employed by the excavator to carry away sediment tailings and to control suspended particulate. The tailings are discharged onto a screendeck barge at the surface, where they are continuously monitored and sampled. Fossils, artifacts and botanical materials exposed on the bottom are mapped, still-photographed and videotaped in place before removal and conservation. In situ sampling for bulk sediment analysis and radiocarbon dating is performed at stratigraphic intervals not exceeding 20 cm.

Diving is accomplished using surface air supply to AGA masks, backed up by completely independent scuba rigs. Wireless communication units fitted to the AGA masks coordinate routine activities of the dive team with surface support personnel, as well as providing an additional layer of safety to the operation.

University of Florida's Dive Safety Officer Dr. Robert Millott placed the resources of the Diving Science and Safety Program at the disposal of last year's ARPP operation, certifying 15 new project volunteers, including instructors, divemasters, research divers and divers-in-training, all to AAUS standards. Dive locker support and trained personnel from the Academic Diving Program at sister institution Florida State University also played a significant role in last year's success.

Approval in 1995 of a substantial multiyear grant from the Florida Department of State, Division of Historical Resources, in addition to continued funding from National Geographic Society and unprecedented private benefactor support greatly expanded the project's ability to safely and efficiently explore these world class sites. During the sixteen weeks of field operations conducted last year a record-breaking 557 dives were logged, accumulating 794.6 hours of total bottom time; all without a single dive-related accident.

Volunteers are recruited from academia and the avocational community in order to maintain a crew of 10-12 divers and 2-4 non-divers every day of our monthlong, and six-weeklong campaigns. In 1995 forty-five hardy souls came from all walks of life across the nation, donating their time and talent for anywhere from five days to six weeks. Volunteer application forms for the 1997 field season (May 6 through June 20 and October 6 through November 1) are available via the project's annual news magazine, The Aucilla River Times. A free subscription is available upon written request from:

Florida Museum of Natural History
Attention: Dr. S. David Webb
University of Florida
Gainesville, FL 32611

Volunteers from institutional members of AAUS are easily integrated into the project because of the reciprocity umbrella.