A group of scientists departed from the coast of Louisiana late Thursday, July 29 for an 18-day research mission focusing on World War II shipwrecks in the Gulf of Mexico. They hope to learn more about how the sea affects the structure of the ships and how the sunken structures interact with the undersea environment at various depths.

The research vessel HOS Dominator left Port Fourchon, Lousiana, at the mouth of the Mississipi River with a full team of scientists and technical personnel aboard. They have two main objectives, to chart and study shipwrecks as historic sites and to study how these man-made structures have interacted with the undersea environment.

The Gulf of Mexico represents one of the greatest concentrations of ships sunk by German submarines, known as U-boats. There were 56 ships sunk in 1942 and 1943, including one of the U-boats, the U-166, which is registered by the German government as an undersea grave site. Since these ships went down at depths ranging from two thousand to six thousand 500 meters, they provide an opportunity for scientists to see how water depth affects the formation of artificial reefs from man-made structures.

Marine archaeologist Jack Irion is one of the investigators who will be on the mission.

"It is almost a perfect laboratory because they were all sunk within one or two years of each other, for the most part, in some cases months of one another, although in varying depths," he said.

Mr. Irion says the German U-boat broke in two after it was sunk by U.S. ships in July, 1942. Although it now rests on the sea floor one thousand 463 meters below the surface, Mr. Irion says it is well preserved.

"It is all quite visible. There is very little sediment on top of it. It is easily recognizable for what it is," he said.

One question in this study is the effect that sea organisms have on the ship structures over time. Jack Irion has studied the wrecks of wooden-hulled ships from as far back as the Bronze Age in the Mediterranean region. He says those structures were well-preserved by sediment and mud, whereas the ships in the Gulf of Mexico are mostly exposed. He says scientists once thought that ships at great depth would be protected from harmful organisms that cannot survive there. But he says recent studies of other wrecks, including the Titanic passenger ship that sank after hitting an iceberg in the north Atlantic in 1912, have changed that thinking.

"What we are finding in fact that there are other organisms that attack them just as voraciously," he explained. "Things like microbes, which no one really expected, which we are seeing on wrecks like the Titanic, that are virtually destroying it. Our interest, in that particularly, is how these things are being preserved over time or not being preserved over time."

The 18-day study of shipwrecks in the Gulf of Mexico is being sponsored by the Department of Interior's Minerals Management Service and the National Oceanic and Atmospheric Administration.