In the Breath of the Forest

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by Neil Caudle

hink of the rain forest as a kind of box, with the canopy as its ventilated lid. Air moves in and out at varying rates, carrying gases. Martens knew that if he could determine the ventilation rate for radon, then he could determine the ventilation rate for any other gas, including greenhouse gases such as methane and carbon dioxide.

So Martens, who had never worked in South America, who had never sampled radon or any other gas in a rain forest, sat down and began to craft a proposal that, by conventional wisdom, should have stood a snowball’s chance in, well, Amazonia.

"We had never worked in Brazil," he says. "We were strictly Northern Hemisphere. People doubted our proposal could survive."

But survive it did, because Martens had something nobody else could offer: the most sensitive radon-detecting instruments in the world and experience using them out of doors.

The instruments are deceptively domestic. Kitchenware is involved.

"We have to be clever," Martens says, "because nobody wants to fund what it really costs to invent these things."

The portable version of the team’s "fluxometer," used to measure radon coming out of the soil, is housed in a metal crock pot. The larger version is a Presto pressure cooker with a metal probe in its belly and a plastic box full of circuitry bolted to its lid.

"Presto gives us a discount," Martens says.

he wizard behind the electronics is Steve Woodward, a design engineer who has retired from the university but who has some trouble resisting an interesting project. About eight years ago, Woodward, Martens, and Howard Mendlovitz, a chemical engineer, began tinkering with designs for a new kind of radon detector, the details of which Martens won’t reveal until the patent is granted. After testing a series of prototypes, the team arrived at "a real winner," Martens says. The instrument proved itself in Duke Forest, where Martens and his students have been studying gas exchange for a project funded by the Department of Energy.

For the work in Brazil, Martens wanted to track the effects of land use on atmospheric gas exchange. South of Santarém, NASA scientists had already staked out the two sites he needed—one scheduled for selective logging, the other along the Tapajos River in a national forest that would remain undisturbed. At each site, the LBA project erected a 220-foot tower. The Martens team would place tubing at eight elevations on each of the towers, piping air from the tubes into an array of detectors housed in shelters on the ground. Laptop computers would control the detectors and compile the data.

"Radon in the air produces daughters," Martens explains, "and the science of counting the daughters involves a bunch of analytical chemistry. We’ve been doing it for years, and we can actually measure radon on the fly. So we’re able to operate the detectors continuously, except when we’re doing intercalibration exercises, when we take the air from one altitude and make sure the detectors can see the same number."

But pots and pans full of nifty electronics aren’t enough, when you go to the rain forest. You need an experienced team. In addition to Mendlovitz, an indispensable research partner, Martens has found two Brazilian collaborators—Osvaldo Moraes of the Universidade Federal de Santa Maria and Reynaldo Victoria of the Universidade de Saõ Paulo. Patrick Crill of the University of New Hampshire, one of Martens’ former students, also brings experience to the team. But the job of handling the fieldwork called for a rare type, a pioneer sturdy enough and resourceful enough to camp in the jungle for weeks at a time, endure the heat and rain and snakes and bugs, keep the instruments tuned up and running, supervise a pair of Brazilian students, and stay alive.

Martens found her. She was Mary Menton, an impressive six footer and recent Phi Beta Kappa graduate in environmental science from the School of Public Health. Menton wanted an adventure before she headed off to graduate school at Oxford University, and she’d been through the Portuguese-language program at Carolina, which Martens calls "the best in the country."

So the core of the team was complete. And one day last April, Martens, Menton, and company drove an hour south from Santarém, turned off the hard surface, slogged their truck along a logging trail more waterway than road, hiked into the forest, and arrived at the foot of a tower so tall that it punctured a cloud. The team would have to attach eight gas-sampling tubes to that tower, at intervals all the way to the top. Brazilian trainers would show them how to use the safety gear—climbing harness, guide wire, and rope. But the climbing itself would be up to the team.

At this point, the term team leader lost a certain amount of appeal. Martens, a sea-level sort of guy by nature and profession, wasn’t wild about heights. Yes, he had climbed other towers but nothing like this. And now, someone had to raise the pulley.

Next: 100 degrees, 99 percent relative humidity

© 2001 Endeavors, The University of North Carolina at Chapel Hill. All rights reserved.