UNM grad student lands in science journal

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ALBUQUERQUE, N.M. (AP) — Scott Jasechko used his road trip from Canada to Albuquerque, where he was about to start a graduate program at UNM, to gather water samples.

Less than two years later, his study of those water samples has landed him in Nature, the prestigious science journal. Jasechko is the lead author of "Terrestrial Water Fluxes Dominated by Transpiration," a study that found plants use a vast amount of fresh water in their life cycles, which can help predict future climate change effects on water resources.

That Jasechko, a doctoral candidate in Earth and Planetary Sciences, was published in Nature is "absolutely huge" and "quite remarkable," study co-author Peter Fawcett said. Fawcett, a UNM associate professor, helped supervise Jasechko, along with second co-author Zach Sharp, also a UNM professor. They worked with three scientists from Alberta Innovates, a Canadian research institution.

Fawcett said he can't recall any other graduate student in his 16 years or so at UNM who was lead author on a study in Nature.

The study is "really significant because it tells us that if we actually change vegetation in a significant way, we can really alter the flux of water from the surface to the atmosphere," Fawcett said.

Jasechko, a Canada native, began collecting samples in summer 2011 when he was driving down from Canada to Albuquerque. He took water from the Great Lakes, Lake Mead, Yellowstone and Jackson lakes, Lake Winnipeg and Elephant Butte on his drive down.

Later, Jasechko compared those samples to others gathered by scientists around the world. In total, he analyzed water from 73 lakes to find that the amount of fresh water that plants use during their life cycles accounts for the biggest movement of fresh water on Earth. Jasechko did this by analyzing the isotopes of oxygen and hydrogen found in the water samples, or what is essentially the "memory" of the water molecules.

The amount of fresh water plants use is more than 1 1/2 times the movement of water in all of Earth's rivers, Jasechko found.

The findings are groundbreaking in that, until now, there was no distinction between the amount of water that comes from evaporation and the amount produced by plants. Jasechko and his co-authors found that plants account for most of the water sent back into the atmosphere.

But high carbon levels reduce the amount of water plants release. Therefore, increased carbon levels in a warmer climate could affect water availability, Jasechko said.

"Where we'd like to take these results now is to explain how vegetation will change in a future warmer climate and what implications that will have for future fresh water resources," Jasechko said. "This research poses new questions and insights into how future fresh water resources will respond to a warmer and carbon-enriched atmosphere."

Jasechko, who expects to complete his Ph.D. next year, submitted the article to Nature last fall. Its publication comes after a rigourous months-long peer-review process.

Jasechko said the study would not have been possible without a grant from the Caswell Silver Foundation or his mentors, Sharp and Fawcett.

"I think the research really shows how important funding graduate students really is for the university," Jasechko said.