42 | New Scientist | 8 June 2019
BNPH
OTOS/GETT
YFeatures
I
T IS summer on Herschel Island in the
Canadian Arctic and Haydn Thomas is
digging in the tundra for teabags. One
in particular eludes him. He knows he left it
around here last year, but now it is nowhere
to be found. “Foolishly, I buried it where the
permafrost is very unstable,” he says. An hour
or more later, he abandons the search. This is
one that got away. But it is a small defeat: there
are at least 5000 more teabags waiting to be
recovered from tundra around the world.
It may seem bizarre, but burying teabags
is all the rage among ecologists. “It’s like a
treasure hunt, trying to find them after
you’ve left them somewhere for a year,
sometimes two years,” says Isla Myers-
Smith at the University of Edinburgh, UK,
who supervises Thomas’s research. “I like
a good treasure hunt,” she says.
Of course, there is more to it than fun.
Teabags, it turns out, provide an ingenious
window onto a largely hidden world: soil.
When soil litter – dead leaves, twigs and other
organic material – decomposes, it emits carbon
dioxide, which contributes to global warming.
Being able to measure the rate at which this
happens is important – and nowhere more so
than in the Arctic, where the tundra holds vast
quantities of carbon and is emitting it into the
air at an accelerating rate as the land heats up.
Sizing up this problem should allow us to
better predict the ramifications of a warmer
world, and chart a course to avert disastrous
climate change.
So how did teabags become a secret weapon
in understanding the biggest problem the
world faces? It started in 2010, when Joost
Keuskamp and Judith Sarneel at Utrecht
University in the Netherlands had a eureka
moment. Both study soil decomposition, and
their research entails painstakingly sewing or
gluing together the seams of hundreds of tiny
bags, filling them with dead plant material,
then weighing and burying them in the
ground. The ecologists later dig up the bags
and reweigh them to track the progress of
decay. During a well-earned tea break, the
pair were bemoaning the tedium of this time-
consuming job. If only there were some way
to avoid it, they mused, while staring into
the depths of their teacups.
Teabags! It was a genius idea. Not only would
using them bypass all the sewing and gluing,
but if ecologists everywhere buried the same
type and brand of teabag instead of homemade
litterbags, it would also give them a standard
piece of kit with which to do their studies.
Soil decomposition occurs when
microorganisms, including fungi and bacteria,Trouble
brewing?
An ingenious experiment is using the
humble teabag to probe worrying carbon
emissions in the Arctic, finds
Lesley Evans Ogden