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"We have a 'bank' of bacteria that we
know is found in the soil in Svalbard's
wetlands. Currently we are examining
the entire microbial community found in
these wetlands to better understand the
turnover of organic carbon and met-
hane production in the Arctic climate,"
Svenning says.
One of her co-workers is Alexander
Tveit, a PhD candidate with extensive
experience in conducting biological
surveys. He uses an advanced molecular
technique called pyrosequencing.
"This method makes it possible to look
at the entire biological community, as
opposed to experimenting with indivi-
dual bacteria, which has been the most
common approach to date. This is a
much faster way to identify unknown
bacterial activity. You can also use this
approach to describe the kinds of orga-
nisms in the soil," he says.
Complex analysis for climate
answers
"We take samples from several wetlands
on Svalbard, and in each wetland, we
have several sampling points. Samples
from these points are mixed together so
that you have a representative sample of
bacteria for the wetlands. We are mainly
interested in the top 30-40 cm of the soil,
" says Svenning.Researchers mix the soil
with various chemicals, which is then
centrifuged and processed in several
steps, after which the DNA can be sepa-
rated out. If this DNA is analysed, it is
possible to determine how much of the
various active bacterial types are found
in the soil.
"This information is analysed using da-
tabases from all over the world, against
which we can compare these genes. Abo-
ut half of all of the sequences get a 'hit' in
the database. We can then see the codes
from the hits for a specific function, such
as breaking down methane," says Tveit.
This kind of comparison doesn't allow
researchers to say much about indivi-
dual bacteria, but it does enable them to
say approximately how many bacteria
there are in the soil sample that have the
specific characteristic for which the gene
sequence codes.
"Our goal is to identify as much as pos-
sible, but much will remain unknown.
Even with a couple of hundred thou-
sand of these sequences, we still won't
get enough good hits. And soil is very
difficult to work with, because many bio-
logical and chemical processes take place
there," concludes Tveit.
There used to be many
hummocks in the bogs
around Neiden in Sør-
Varanger municipality.
But these hills, called
palsas, are now dis
appearing as a result of
climate change.
The University of Tromsø is participating
in a project supported by the EU that is
monitoring methane-oxidizing bacterial
flora in different ecosystems. For their
part, UiT researchers are examining what
is going on with the palsas found near
Neiden.
Palsas are caused by permafrost. A palsa
is essentially a turf-covered mound,
with a core of ice that rises above the
surrounding bog or water surface. The
height of the mound varies from less
than one metre to several metres, with
an area that may cover several hundred
square metres.
A palsa bog system can be very dynamic
over time as a result of the formation,
growth and breakdown of the palsas.
Monitoring data show that palsa bogs in
Norway are being altered as a result of
climate change. Rising temperatures and
more precipitation cause permafrost to
thaw, which in turn decreases the area
covered by palsa bogs, according to the
Norwegian Institute for Nature Research
(NINA) website.
"Palsas are great mounds of soil – but
when their ice cores melt, they are
transformed into puddles of stagnant
water. Now we will investigate what it
is happening in these palsas. They are
full of organic material and when they
melt, it's easy to believe that methane is
released. We will investigate how much
methane escapes from palsas," says Mette
Svenning.
Hills or mounds on the landscape
usually suggest an underlying geological
structure, but not always. The planet is
home to amazing biological processes
that may explain much of what happens
in the ground.
"A really great palsa in Neiden disappea-
red over the course of just four years. An
elderly local man told us that there were
many of these formations in the lands-
cape when he was a child. Now there are
only a few left. And we don't yet know
whether more methane is released when
these palsas disappear," Svenning says.
University of Tromsø –
Labyrint E/11
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21
Text: Maja Sojtarić
As the ice melts, the palsas disappear. All that is left is a
puddle of water. Photo: Annika Hoffgaard
Disappearing palsas