MARINE BIOLOGY?
“I fell in love with Tromsø. When I was here
for the first time, I realised that this was where I
had to live,” says Marek Cuhra, a PhD candidate
in the University of Tromsø’s Faculty of Health
Sciences.
He had met a girl from Tromsø in
Copenhagen, and persuaded her that they had
to move back to her hometown. Today he has
five children in Tromsø, and a new girlfriend.
He still has his love of the sea, the mountains
and the scenery – which is why he studies water
fleas.
Yes, you read that correctly.
If you are interested in the health of the
environment, these five-millimetre-long crus-
taceans, commonly known as water fleas, can
provide some very interesting information.
“Water fleas are fantastic. Because they have
a life cycle of only 42 days, we can see how,
for instance, the common herbicide
Roundup
affects them from birth, reproduction to death.
If we studied any other animals, such as rats or
mice, we would need up to two years for a single
experiment. It would be very expensive,” says
Cuhra.
Water flea abortions
Cuhra’s research now shows that water flea
mothers are strongly affected when they are
found in water near agricultural areas where
Roundup is sprayed on crops.
In short, water flea mothers abort in these
situations, and cannot give birth to live young.
The reason is that Roundup contains glypho-
sate, a substance that kills weeds, but that is
tolerated by genetically modified plants, such as
corn and soy.
“We only see the ecological effects, and our
findings on water fleas cannot in any way be
extrapolated to humans and animals. But it is
interesting that water fleas, which usually give
birth to 20–25 young every three days starting
when they are one week old, are unable to bear
live young when exposed to only 1.35 ppm of
glyphosate per litre of water,” he says.
Photographs of water fleas
Cuhra has analysed the young of living and
dead water fleas as well as their mothers in his
Tromsø laboratory. Keep in mind, however,
that we’re talking about very small creatures
– newborn water fleas are only 0.8 millimetres
long.
“The study involved 220 water flea moth-
ers, and we spent thousands of hours on this
and subsequent research. Every sixth day, we
photographed the young water fleas under the
microscope. They are vulnerable little crea-
tures that you can gently move around in small
water droplets. It is a real skill to handle these
Marek Cuhra
PhD candidate Marek Cuhra conducts lab-
oratory studies of abortions in water fleas.
Every third day, a water flea normally gives
birth to 20–25 live young, but if the animals
are exposed to glyphosate from pesticides in
the water, the young are stillborn.
Photo: Elisabeth
Ø
vreberg
Just how did a
Danish-speaking
Czech end up in Tromsø
researching
abortions in water flea mothers?
The answer is love.
Text: Elisabeth
Ø
vreberg
38
labyrint
•
research magazine
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u
i
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arctic
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