Monday, July 16, 2007
A UC Irvine scientist says her years of study in the Amazon basin revealed unmistakable signs of global warming.
By PAT BRENNAN
The Orange County Register
She faced grueling climbs, rocky boat rides, dangerous mountain villages, stomach-wrenching illnesses – even bad-tempered, spitting llamas.
But UC Irvine scientist Amy Townsend-Small, 30, laughs about the troubles she encountered on her trek through the Amazon River basin and the Andes Mountains.
What really disturbed her was the condition of the river itself. Her repeated visits to the Peruvian back country over the years revealed an unmistakeable trend: one of the world's wettest ecosystems was getting very, very dry.
"I was in a boat that ran aground," she said of her last trip, in 2005. "This is the biggest river in the world. It's not normal for that to happen."
Townsend-Small is a biogeochemist – someone who studies the relationship between molecules and the living environment. She and her co-authors have published some of their findings, and recently completed a broader series of papers they are also seeking to publish in a scientific journal.
She hopes to help the public, and other scientists, to understand the dramatic changes occurring in the Amazon.
"These changes are faster than you would expect a natural system to change," she said.
The goal of her studies so far, completed with the help of Peru native and ecologist Jorge Noguera, was to learn whether nutrients from the Andes, which tower over the westward edge of the 2.7 million-square-mile Amazon basin, are carried from the Amazon River's mountain headwaters to its rich tropical bottomlands.
And, using cutting-edge analysis that matched carbon molecules found downstream with plants and soil in the mountains, she found that the Andes really do nourish, and help shape, the chattering, screeching forest stretching from horizon to horizon below.
"There's a lot of transfer of soils and plants from the terrestrial environment to rivers," Townsend-Small says – that is, when it's raining.
Rainfall in the basin is normally heavy. But Townsend-Small happened to conduct her study at a time of transformation for the Amazon, and the Andes range as well.
"A lot of changes are happening," she said. "Glaciers are melting fast. The rivers are starting to dry up a little bit. It wasn't my intention to study that, but it turned out I happened to be there during a very dry period."
Her observations heightened her concern about something other researchers had predicted: climate change, combined with deforestation, could eventually wipe out the famous Amazon rainforest.
"A lot of scientists, including me, think the Andes and the whole Amazon is going to get drier and drier as climate change progresses," she said. "Atmospheric chemistry modelers predict the Amazon is going to turn from a rainforest to a grassland because of deforestation and climate change.
"There are spectacular forests that are literally submerged – their roots are submerged – during floods," she said. "Without the nutrients and water from the Andes, those won't exist."
Townsend-Small's most recent trip began in May 2005 with a flight from Texas to Lima, Peru. From there, she took a 12-hour bus ride over the Andes Mountains and into the Amazon River drainage.
She set up her base of operations in a tiny mountain town called Oxapampa, then took forays into the wild to collect soil, plant and water samples, first in the mountains and then in the river basin.
During this trip and another the year before, one of the first signs of climate change Townsend-Small noticed was in the river and its tributaries.
"The rivers were much clearer," she said. That was not a good sign.
"There wasn't a strong connection between the landscape and the rivers," she said. "We were starting to see more plants growing in the river than ever before."
The unusual clarity meant nutrients were not flowing downriver as they had in 2002, the first year of her study, when rain was abundant.
The water levels also were low. The clear water allowed more penetration of sunlight, spurring the growth of aquatic plants.
Townsend-Small had to wait for a push from a second boat when one she was riding in went aground in a part of the river used for shipping – an extremely unusual occurrence, according to locals, who also were taking note of the extreme dryness of the basin.
There were other hardships. Some of the South American cities and towns, she said, were plagued by crime and pollution, and she and her colleagues suffered severe gastrointestinal illnesses from drinking local water.
"Trying to backpack when you're sick is scary," she said. "Especially on those cliffs."
And as for the llamas used during part of the trip as pack animals – well, Townsend-Small tried to make friends.
"I thought they were going to be really friendly, but they weren't," she said. "They were mean. They spit, like camels. You can't pet them or anything. And they smell really bad."
But, aside from the troubling signs of global warming, Townsend-Small said her travels in South America were mostly a delight.
"The whole thing was a life experience," she said. "It was physical, emotional, intellectual. I think it's a fascinating system, and a wonderful place to work."
Contact the writer: environment editor Pat Brennan at 714-796-7865 or pbrennan@ocregister.com.
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