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High-tech undersea search for the first Americans

By Moises Velasquez-ManoffCorrespondent of The Christian Science Monitor / March 14, 2007


Inside a darkened room, oceanographer Robert Ballard stares at an array of flat-screen monitors. The monitor to his left shows a crew of scientists aboard the submarine support vessel Carolyn Chouest in the Gulf of Mexico. On a monitor to his right, a roomful of Rhode Island high school students are intently focused on something unseen. And directly ahead, a large plasma TV plays live footage of what's holding everyone's attention: the ocean floor some 115 miles off the Texas coast.

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The picture is transmitted by Argus, an unmanned submersible 1,800 miles away from the Mystic Aquarium in Connecticut. In fact, Dr. Ballard is presiding over the first undersea expedition conducted entirely by remote control. "It's the first time I've had enough confidence in the technology to step ashore," he says.

The subject of his search, as well as its location, are as precedent-setting as the means he's using to conduct it.

Enabled by technological advances such as satellite uplinks and the next generation of Internet, the expedition is a step toward Ballard's vision of a world experienced via "telepresence" – not in person, but via remotely operated cameras and sensors. It's cheaper, requiring less manpower than typical science expeditions. It also has profound implications for any kind of undersea exploration, especially for the nascent field of ocean archaeology.

Today, Ballard and his team are seeking submerged evidence of the first Americans. Any proof of past human habitation in this area of former coastline could sink a long-dominant – and many say hopelessly eroded – hypothesis about who the first Americans were, how they got here, and when they arrived.

"It's a great story in human history," says Kevin McBride, a professor of anthropology at the University of Connecticut at Storrs, who is involved in the project. "And as usual, it's a more complicated story than people think."

With the help of the US Navy's only research submarine, NR-1, Ballard's team is mapping the area to determine where early Americans might have lived when the Gulf's underwater hills sat at shoreline. At the height of the last ice age, sea levels were nearly 400 feet lower than they are today. The team's voyage began March 4, along a series of rises called the Flower Garden Banks. Scientists think the area, now filled with colorful sponges and abundant sea life, was a thriving coastal estuary 19,000 years ago – and prime real estate for human habitation.

Dwellers on an ancient coast

An abundant amount of salt left from an even earlier time when a closed-off Gulf of Mexico completely evaporated would have provided an invaluable resource for preserving meat. Salt licks also would have attracted grazing animals and potential game. Inhabitants would have also found the coastal estuary full of easily harvestable shellfish, and if they ate shellfish, they probably left behind large piles of discarded shells that scientists can radiocarbon date. Because of the continental shelf's gradual incline in the area, rising seas would have quickly inundated the land, increasing the chances that artifacts were preserved.

This is Ballard's high-tech quest: proof of human habitation in the Gulf. That might refute the classic hypothesis that the first humans in the Americas were Siberian hunters, who followed herds over the Bering land bridge some 11,500 years ago. The hunters, the theory goes, passed into the interior of the continent via an ice-free corridor on the east side of the Canadian Rockies. Archaeologists call them the Clovis culture, after a distinctive spear point found near Clovis, N.M., in the 1930s.

But in the past 20 years, archaeologists have excavated many sites with radiocarbon dates older than the Clovis culture. Tools and shelters at Monte Verde in Chile are 12,500 years old. Stone flakes and fire pits found at the Meadowcroft Rockshelter in Pennsylvania date to 14,000 years ago – before the corridor to the interior would have been open. This observation gave birth to an alternate hypothesis: Perhaps the first Americans skirted the glaciers in boats.

An ice-free corridor inland

Bolstering this possibility, scientists now think that a sliver of coast between the great Cordilleran glacier on the Canadian Rockies and the Pacific Ocean remained clear during the Ice Age.