1. Deep Thoughts
NotesfromtheundergroundbyCommunicationsDirectorConstanceWalter Monday, April 25, 2016
South Dakota Science and Technology Authority Lead, South Dakota
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Microbial life abounds on the 4850
The 17 Ledge on the 4850 Level of
Sanford Lab is hot and muddy.
Temperatures hit 95 degrees with
98 percent humidity. Water reaches
mid-calf and the mud is like gumbo—a
thick, sticky goo that can stop you in
your tracks if you’re not careful. But it
didn’t slow down Oxana Gorbatenko, a
research assistant at Black Hills State
University (BHSU), or Bethany Reman,
a BHSU undergraduate. The two are
part of a research group searching for
life in microbial communities living
deep underground.
“These communities have been
living under odd and, perhaps, novel
circumstances,” Reman said. Bacteria,
archaea, fungi and eukaryotes live in
microhabitats that are ecologically iso-
lated. They face nutritional limitations
and extreme geochemical and physical
conditions—a perfect environment for
extremophiles. They have also been
shielded from the effects of cosmic
rays and fluctuating temperatures,
all of which has an impact on the
microorganisms.
Of particular interest to the BHSU
group are the eukaryotes. “Up to now,
little research has been done on them,”
said Cynthia Anderson, associate
professor of biology at BHSU. They
want to better understand the affect
of human activity on these unique
ecosystems; characterize their compo-
sition; monitor changes in the com-
munities; and look for novel metabolic
products that have potential uses as
antibiotics, or in processes such as
cellulose degradation.
The team originally began collecting
data on eukaryotic microbial diversity
in 2007. “New DNA sequencing tech-
nology will allow us to obtain a more
detailed picture of the eukaryotic
diversity present in various habitat
types,” Reman said. New data col-
lection began in March and includes
samples from the 800, 1700, 2000,
4100 and 4800 levels.
Gorbatenko and Reman walked
slowly through the hot and humid
drift, shining their cap lamps on every
surface. At one point, Reman pointed
at a particularly large growth on a
cavern wall. “Thiothrix Falls,” she said.
“Do you want to collect a sample?”
(The falls are a flow from a legacy drill
hole. They were for a microorganism
found in the water.)
Gorbatenko stepped closer, a clear
plastic tube in her hand. She looked
closely at the growth then began
scraping a sample into the tube, which
she then stored inside a cooler. The
two also collected samples from
biofilms resting on pools of water,
slime from cavern walls and growth
on a wood shelf left over from mining
days.
After 45 minutes, Gorbatenko and
Reman began the trek out of the 17
Ledge drift. A locomotive took them
to the Black Hills State University
Underground Campus (BHUC) where
they could look at the samples col-
lected. In the past, the samples would
have been taken to the surface then
to a lab at BHSU. But the addition of
the BHUC and its biology component
allow researchers to assess samples as
soon as possible after they are col-
lected. “It is possible that the collected
samples and living things in them
could be highly sensitive to being
disturbed, and we want to view them
while they are still living,” Anderson
said.
Using phase contrast and dark field
microscopy the team watches light
waves traveling through the specimen,
creating variations in brightness and
making the specimen more visible.
“This is an important technique as it
allows visualization of living cells/
animals without staining or killing
them,” Reman said.
It was the first time Reman and
Gorbatenko had looked at samples
underground. As the images of fungi,
rotifers, bacteria and, possibly, a
gastrotrich, appeared on the computer,
the excitement in the lab was palpable
and the two began planning the next
trip to 17 Ledge where life abounds.
Photo by Constance Walter
Oxana Gorbatenko collects a sample from growth on a cavern wall at the 17 Ledge.