How do you save the “skin” of the desert?


Biological crusts may have evolved to withstand droughts, but not humans.

The wall built on the United States-Mexico border runs along the southern border of Organ Pipe Cactus National Monument. Border patrol vehicles kick up a near-permanent cloud of dust as they drive back and forth through what was once the most important habitat for biological crust. When Antoninka arrived in the area to assess the impact of traffic and construction machinery on the crusts, she made a predictable discovery: the crusts are not doing well. Every step he takes kicks up a small cloud of fugitive dust because there is no biological crust holding the ground in place during the summer monsoon.

This disappearance affects Antoninka personally, who studies biological crusts as if making old friends. ” Here is a Heppia ! And a colleague ! she calls. That day, as she defines the scab collection area for her team, she is delighted to discover a surprise formation. Crouching down, she takes a closer look at the dark stain on the beige sand. “Ooooooh how pretty you are! Hello in there! »

Dismayed by the mass disappearance of biological crusts in the Southwest United States due to construction, fires, and other human activities, Antoninka and Bowker are now growing their own crust in the lab. Their goal is to create candidates for transplantation to help restore biological crusts.

It was this project that led Antoninka and her team to the Sonoran Desert to collect fragments of healthy biological crust from Organ Pipe National Preserve and Tonto and Casa Grande National Monuments. The healthy crust taken by the scientists at these three locations will be used as seeds for culture in the laboratory.

Luckily for the researchers, they only need small pieces, because organisms in the biological crust are totipotent: each individual cell can reproduce the whole organism under the right conditions.

And it’s hard to understand by appropriate. With their constant temperature, shade, and humidity, greenhouses offer far too peaceful a life for organic crusts. In this environment, experiments fail. Outdoor plots protected from extreme heat and drought are the ideal recipe for hardening off these tiny plants without killing them. The team is currently growing new crusts on jute and other biodegradable substrates that will facilitate transport and establishment in a new environment.

“Antoninka is at the forefront of the movement. That’s what drives the discipline so quickly,” says Akasha Faist, an ecologist and grassland scientist at New Mexico State University. For years, ecologists have waited for the biological crust to reform, but efforts by Antoninka and other researchers have begun to accelerate this natural process.

So far, researchers have grown the biological crust based on the conditions of its original location. However, Reed’s work at the United States Geological Survey has shown that even the slightest change in temperature and precipitation can be deadly to these organisms, which are already on the brink. Instead of cultivating the crusts in the current conditions, Antoninka wants to place them in warmer and drier places to prevent global warming.

“You have to stop worrying about the current situation and look to the future,” says Antoninka. “I don’t know if it will work, but we have to try. »

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