Scientific American 201907

(Rick Simeone) #1

DISPATCHES FROM THE FRONTIERS OF SCIENCE, TECHNOLOGY AND MEDICINE


JOIN THE CONVERSATION ONLINE Visit Scientific American on Facebook and Twitter

INSIDE


  • Kaleidoscopic lamps made from microbes

  • What it is like to live in space for a year

  • Developing a better kind of IQ test

  • A pacemaker powered by the heart’s
    own beat


GETTY IMAGES

MICROBIOLOGY

Dead Sea Life


Evidence of ancient bacteria in
the lake’s sediments may point
to past life on Mars

The Dead Sea is not all dead. Sure, it is
one of the most extreme ecosystems on
our planet, with a salinity so high that tour-
ists can easily float atop its dense, briny
brew. And with no plants, fish or other visi-
ble life, swimmers can be excused for as-
suming that nothing stirs in the deep. But
long ago scientists discovered single-celled
microorganisms called archaea living in the
lake’s waters—causing many to wonder
whether other simple life could also survive
within the sediments below despite the ab-
sence of oxygen, light or nutrients.
Now Camille Thomas, a geo micro bio-
logist at the University of Geneva, and his
colleagues have unearthed molecular fossils
in Dead Sea sediments that suggest bacteria
lived there as recently as 12,000 years ago.
It is the first time scientists have discovered
a life-form other than archaea in this eco-
system—which hints that such life might
exist (or have existed in the past) in similar
places across the globe and else where in
the solar system, including Mars. The re -
sults were published in March in Geology.
Thomas and his colleagues were part of
an international collaboration that in 2010
drilled 430 meters below the lake bed in
an unprecedented opportunity to better
assess our climate’s past. After several
years of analyzing the samples, Thomas’s
team found archaea buried within the sedi-
Free download pdf