The Scientist - USA (2019-12)

12.2019 | THE SCIENTIST 17

Notebook

NEWS AND ANALYSIS

COURTESY OF ARMANDO AZUA-BUSTOS

DECEMBER 2019

Riding the Wind

E

very morning for a week last year,

astrobiologist Armando Azua-Bustos

drove into the Atacama Desert

and set up long lines of petri dishes. A

researcher from the Center of Astrobiol-

ogy in Madrid, Azua-Bustos wanted to see

if he’d be able to catch any microbes with

the dishes, and whether those microbes

might start to grow.

He and his colleagues kept their

expectations low. The Atacama Desert,

which stretches about 1,000 kilome-

ters along the coast of northern Chile,

is the driest place on Earth—some spots

haven’t seen rainfall in 400 years—and

it’s blasted daily by ultraviolet radiation.

Conditions are so harsh that the desert

serves as a proxy for the surface of Mars,

with scientists sending Red Planet rovers

there for testing. For much of the 20th

century, scientists wondered whether life

could even survive there.

About 15 years ago, researchers dis-

covered traces of bacterial RNA—though

no DNA or cells—in the surface of what

was then considered the driest part of

the desert, a spot called Yungay (Sci-

ence, 302:1018–21, 2003). The following

year, that team and others reported find-

ing microbial DNA underground in the

region, a clue that organisms might get by

with just tiny amounts of water (Science,

306:1289–90). A decade later, Azua-Bustos

and colleagues confirmed those results,

showing that microbes survive beneath

the soil at María Elena South, a region

now known to be even drier than Yungay

(Environ Microbiol Rep, 7:388–94, 2015).

One of the questions that arose from

those studies, Azua-Bustos says, was “how

do these species get there in the first place?”

He says he was reminded of his childhood,

growing up in a mining town just 15 minutes

from María Elena South. The mornings, he

remembered, were quiet, but later in the d ay,

a dusty breeze developed from winds blow-

ing in off the Pacific Ocean and grew stron-

ger as afternoon turned to evening each d ay.

“Knowing Atacama is a very windy place, we

wanted to know whether wind could trans-

port microbial life,” he tells The Scientist.

DESERT DISHES: Researchers set up lines of

petri dishes in the Atacama Desert as part of a

study on microbial transport.