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Category — Desertification

Researchers discover global warming may affect microbe survival

desertsoilcrustutahTemperature determines where key soil microbes can thrive – microbes that are critical to forming topsoil crusts in arid lands. And of concern, Arizona State University scientists predict that in as little as 50 years, global warming may push some of these microbes out of their present stronghold in colder U.S. deserts, with unknown consequences to soil fertility and erosion.
Photo by: Estelle Couradeau

Arizona State University researchers have discovered for the first time that temperature determines where key soil microbes can thrive – microbes that are critical to forming topsoil crusts in arid lands. And of concern, the scientists predict that in as little as 50 years, global warming may push some of these microbes out of their present stronghold in colder U.S. deserts, with unknown consequences to soil fertility and erosion.

The findings are featured as the cover story of the June 28 edition of the journal Science.

An international research team led by Ferran Garcia-Pichel, microbiologist and professor with ASU’s School of Life Sciences, conducted continental-scale surveys of the microbial communities that live in soil crusts. The scientists collected crust samples from Oregon to New Mexico, and Utah to California, and studied them by sequencing their microbial DNA.

While there are thousands of microbe species in just one pinch of crust, two cyanobacteria – bacteria capable of photosynthesis – were found to be the most common. Without cyanobacteria, the other microbes in the crust could not exist, as every other species depends on them for food and energy.

“We wanted to know which microbes are where in the crust and whether they displayed geographic distribution patterns at the continental scale,” said Garcia-Pichel, also dean of natural sciences in ASU’s College of Liberal Arts and Sciences. “To our surprise, where we thought a single cyanobacterium would dominate, we found that two had neatly split the territory between themselves. We used to think that one, called Microcoleus vaginatus, was the most important and dominant, but now we know that Microcoleus steenstrupii, the other one, is just as important, particularly in warmer climates,” he added. [Read more →]

July 4, 2013   No Comments

Allan Savory: How to green the world’s deserts and reverse climate change

“Desertification is a fancy word for land that is turning to desert,” begins Allan Savory in this quietly powerful talk. And terrifyingly, it’s happening to about two-thirds of the world’s grasslands, accelerating climate change and causing traditional grazing societies to descend into social chaos. Savory has devoted his life to stopping it. He now believes — and his work so far shows — that a surprising factor can protect grasslands and even reclaim degraded land that was once desert. [Read more →]

June 10, 2013   No Comments