Underwater forest? 'Enchanted forest' provides tantalizing hints to past climate.
Underwater forest: An underwater forest discovered in the Gulf of Mexico contains trees that lived for hundreds or maybe thousands of years, and died over 50,000 years ago.
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The underwater forest remained a closely guarded secret for years, until Raines, a journalist and diver, tracked down the rumors and headed out with a camera. He shot photos and video footage of what he called an "enchanted forest," but he's keeping the location quiet, for fear of salvage loggers who would turn this unique discovery into furniture.Skip to next paragraph
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Raines's pictures reveal that new life has sprung up from these long-dead trees. More than 50,000 years ago, they rose 80 to 150 feet tall from rivers and estuaries, supporting an ecosystem filled with alligators, snakes, wading birds, and mosses. Now, these submerged stumps and fallen logs, dead since Neanderthal days, have created an artificial reef, supporting a coral-reef-like ecosystem of anemones, spidery arrow crabs, rockfish, red snapper, and more.
While he was down there, Raines picked up a piece of wood off the seafloor and cut loose another one. So far, those are the only specimens that have been gathered from the site. Raines tried to return last fall with Harley and Dr. DeLong, but their boat broke down en route.
Both DeLong and Harley are eager to get back to the forest and gather more samples, in hopes of piecing together a picture of the ancient forest. They're just waiting for the jet stream to warm and calm the waters of the Gulf, which should happen by late summer. They don't want to wait any longer than that – another hurricane could sweep into the area and rebury the site at any time.
"Today, Bald Cypress are sensitive to drought and precipitation," Harley says. If these ancient cousins of the Bald Cypress are as sensitive, their tree rings could reveal the climate in the Gulf Coast tens of thousands of years ago.
"We can match the pattern – the wide and narrow growth rings – and create a chronology that spans, I'm sure, several thousand years," says Harley.
The heart of dendrochronology, or tree ring history, is connecting the story told by the tree rings into an overlapping pattern, daisy-chaining the records from various trees together to create a climate record that is longer than any one tree could ever live. If each of these underwater trees is hundreds or, more likely, thousands of years old, then Harley and his team have "the potential to create a multi-millenial tree ring chronology," he says. This could tell the story of the ancient climate over the course of tens of thousands of years – but which years? That's the other key to dendrochronoloy: an anchor date. If you can get a firm date for just one tree ring, then you can extrapolate forward and backward through the entire chain.
Once they got the news that the two samples Raines had recovered were "radiocarbon dead," the scientists concluded that the trees probably lived during the previous glacial maximum, about 50,000 to 80,000 years ago, though they could theoretically be even older. They're now processing the samples for slower-decaying isotopes, such as uranium-thorium or potassium-argon, in hopes of finding that elusive anchor date. Harley also points out that that when they've collected more samples, odds are good that at least one of the trees will be younger than 50,000 years. "I'd be very surprised if every tree sample came back the same age," he says.
"As long as we're anchored in time by one radiocarbon date, then we could say something pretty cool about the environment, the climate back then," says Harley. "That would be the ultimate goal."
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