Message #136341

[Bianca]

Researchers at the University of North Carolina at Chapel Hill's Institute of Marine Sciences (IMS) have been digitizing historic charts to track past movements of the inlet's channel and associated shoals in the vicinity of Queen Anne's Revenge. Cartographic studies of the inlet through historic times show that the inlet's channel naturally migrated back and forth and appears to have passed over the shipwreck several times. Consequently, the shipwreck was periodically subjected to intense channel currents, while at other times it may have been covered by as much as 20 feet of sand.

The collection of environmental data included daily weather and water conditions that affected work, such as wind strength and direction, wave height, and water temperature and clarity. To further understand environmental conditions, the IMS positioned an electromagnetic current and wave sensor near the site to record current velocity and direction, and wave height and frequency. That instrument, installed in April 1998, remained in place for one year, including the period during which Hurricane Bonnie passed through the area with sustained winds of 75 miles per hour.

The remains of Queen Anne's Revenge are located in a shallow and dynamic coastal environment. Other than the tidal currents, the site is subjected to nearly constant wind-generated wave action that can be catastrophic during hurricanes. During both field seasons, hurricanes situated hundreds of miles offshore produced large, slow waves that rolled over the site and created a surge on the bottom that made it impossible for divers to work. Readings from the current meter were even more dramatic during Hurricane Bonnie; currents registered 2 knots over an extended period. At the height of the storm, an extremely dynamic current surge reached 8 knots and caused considerable movement of bottom sediments. Scouring from those currents was evident, when in 1998 portions of the wooden hull structure were found exposed.

Geologists at IMS have analyzed sediments recovered from beneath both the hull section and several ballast rocks to determine if they contain the radioisotopes Cesium 137 and Plutonium 239 and 240, which have dramatically increased since atmospheric nuclear testing in the 1950s. The lack of significant amounts of bomb-produced radioisotopes indicates that large artifacts have not shifted about the sea floor in the last fifty years, thus giving scientists an understanding of the degree to which the site's archaeological context has been disturbed.

Seawater temperatures, which fluctuate from winter lows in the mid-40s to the low 80s (degrees Fahrenheit) during the summer, are not a deterrent for divers wearing proper equipment. On the other hand, water clarity can greatly affect working conditions. Though visibility can exceed 20 feet at the site, it averages less than 3 feet. Water clarity generally increases during calm weather and when the tide is rising. Water-quality studies conducted by Cape Fear Community College Marine Technology Program (CFCC) technicians recorded salinity, dissolved oxygen, and pH. This information helps the conservators in their efforts to predict the corrosive potential of the environment on metal artifacts.

The exposed wreckage of Queen Anne's Revenge, made up principally of anchors, cannons, and ballast, is a well-developed near-shore artificial reef community lying in mid-Atlantic waters. Biologists from IMS have determined that the wreck has been exposed for the past fifteen years, based on the rate of coral growth. Peter Gillman-Bryan of Truelove Fabrications conducted a biological survey in which he recorded a typical array of animal and plant life at Queen Anne's Revenge. Attached to the reef were varieties of coralline algae, encrusting bryozoans, sponges, corals, barnacles, and oysters. Small brown anemones, sea pork, sea squirts, sea whips, and purple urchins were also noted. Numerous species of fish inhabit the waters surrounding the shipwreck, among them conger eels, toadfish, blennys, filefish, triggerfish, spadefish, angelfish, spottail pin fish, black sea bass, sheepshead, summer flounder, octopus, and rays. Several kinds of crabs feed among the organisms, as did a few types of gastropods such as tulip whelk and apple murex. Divers have also observed a sea turtle on the ballast pile. The dearth of a substantial amount of fishing tackle near Queen Anne's Revenge indicates that the site has been only occasionally visited by recreational fishermen and has been effectively avoided by commercial trawlers, thus minimizing damage to exposed cultural remains.