RWU Magazine - Fall 2013 / Issue #9 - page 21

19
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.
D
elicate
,
gelatinous orbs
invaded
the
tranquil
waters of
the
B
lack
S
ea
in
the
1980
s
,
introduced to the foreign habitat via ship
ballast water. In less than 10 years, the
diminutive comb jelly
Mnemiopsis leidyi
multiplied by the billions and devoured all the
plankton, rupturing the food chain – and
costing a devastating $350 million in fishing
and tourism losses.
Scientists link
Mnemiopsis’s
explosion in
the Black Sea to warming waters, which allow
better winter survival, and commercial fishing,
which reduces the jelly’s competition for food.
With favorable conditions on its side,
Mnemiopsis
(also called the sea walnut) spread
to the Caspian Sea, yielding what may prove
even more crippling results. Even its native
territory along the western Atlantic coast
suffers from its voracious appetite – copious
Mnemiopsis
in Rhode Island’s Narragansett Bay
decimate the annual blooms of copepods, tiny
crustaceans that sustain larval fish.
Why does
Mnemiopsis
invade some waters
but not others? What environmental factors
might encourage or discourage the thriving
swarms? With a grant from the National
Science Foundation and in collaboration with
scientists from two other universities, Sean P.
Colin – associate professor of environmental
science at Roger Williams – intends to answer
these questions.
Inside a workshop well outfitted with
microscopes, aquariums and lasers at the
Marine Biological Laboratory in Woods Hole,
Mass., Colin demonstrates the ancient
creature’s distress in anything but dead-calm
waters. He knocks on the table near a tank of
hovering jellies – they flinch and jet their
flimsy bodies below the choppy surface. His
theory: this voracious feeder consumes
considerably less prey in rough waters.
Colin hopes that field studies will validate
his concept. Scuba-diving scientists will
plunge into the murky waters of Vineyard
Sound to monitor these jellies, as they react in
conditions ranging from a glassy surface to the
biggest chop – and as they monitor, they will
capture images that visually bisect the animals
to learn if
Mnemiopsis
can snare prey when
diving down to avoid damaging waves. Colin
suspects not: “You might drink a cup of water
in sips (and take it all in) or you might pour it
into your mouth and only capture some of it.”
Colin’s research may demonstrate the
vulnerability of bays, harbors and other
sheltered waters to invasions and population
booms of
Mnemiopsis
– and that’s where the
conversation about protective efforts can
begin, he says. “This work is helping to
contribute to our ideas of why they are in one
area versus absent in another area,” he
explains. “Based on these observations, we’ll
learn where we think they’re going to be most
successful and least successful.”
Jill Rodrigues ’05
Dating back more than 500 million years, these primitive creatures are some of the most effective feeders
on the planet – second only to the jellyfish, a distant cousin. Brainless, sightless and composed of 97
percent water,
Mnemiopsis leidyi
drifts along the current and swims via beating cilia along its oval body,
producing a strobing rainbow light show.
Photo:
Sean Colin
Tale of the Uninvited Jelly
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