26 SEP TEMBER 2014 • VOL 345 ISSUE 6204 1553 SCIENCE
helped make Scheffer a leading, and sometimes unorthodox, thinker on the science of
tipping points. Now, at 56, the Wageningen
University ecologist has crossed a threshold
of his own: Flush with funding, he’s become
the intellectual hub for a global network of
scholars who meet for freewheeling discussions, often at a retreat center he built on
his family farm in the Netherlands. The collaborations are carrying Scheffer far from
the rural lakes where he started, to efforts
to identify tipping points in tropical forests,
global climate, and communities of gut microbes, and even in the onset of migraine
headaches and depression.
Scheffer has become “the social glue … the
chief networker in some ways” for a growing
community of tipping point researchers, says
climate scientist Tim Lenton of the University of Exeter in the United Kingdom. Along
the way, he’s won hefty science prizes, and his
key papers have tallied some 10,000 citations.
Some researchers, however, worry that
Scheffer might be moving too far, too fast
with his ideas, and that tipping point models,
while elegant, are sometimes too rudimentary to be very practical. Still, few question
his scientific acumen or skill at shattering
disciplinary barriers. Scheffer’s “
independence is his trademark,” says ecologist Wolf
Mooij, a colleague at Wageningen University
and the Netherlands Institute of Ecology.
THAT AUTONOMY WAS ON DISPLAY in
2009, when Scheffer received the Spinoza
Prize, a €2.5 million award that is the Netherlands’ most prestigious science honor.
Winners typically give a predictable speech.
Scheffer, an accomplished musician, instead
pulled out a guitar and played an original
acoustic composition from Transitions, one
of 15 albums he has recorded.
Once, Scheffer thought he might play music for a living. Raised in the Dutch countryside by parents who played classical flute and
piano, young Scheffer was asked what instrument he wanted to learn. “It was not really a
question” of whether he would take lessons,
he notes, so “I picked [an instrument] they
did not play,” the violin, and studied it
seriously, well into his college years.
When it came time to choose a career,
however, Scheffer tipped toward science. (“I
would never be able to be a [classical] violin player,” he says, given his eclectic musical tastes.) After earning an undergraduate
degree in ecology from Utrecht University,
he eventually landed at the Netherlands’ Institute for Inland Water Management and
Waste Water Treatment.
Soon, Scheffer was wading into the murky
lake problem, putting him squarely within a
long scientific tradition. Some historians argue that modern ecology itself was launched
by the publication of “The Lake as a Microcosm,” an 1887 paper by American ecologist
Stephen Alfred Forbes. Lakes hit a sweet
spot, Scheffer says: ecosystems that are self-contained and experimentally tractable yet
intricate enough to yield profound insights.
“They’re really complex systems but … we
understand them relatively well, and can actually manipulate them,” he says. And in wet,
table-flat Netherlands, Scheffer and his colleagues had plenty of lakes within reach.
Most notably, they showed that clear lakes
with plentiful vegetation are resilient to mod-
erate nutrient influxes, whereas murky lakes
lacking such vegetation cannot easily return
to clarity. The scientists also learned why
“shock therapy”—removing bottom-feeding
fish—can work. They found that the fish stir
up sediment, releasing stored nutrients that
keep lakes murky even after external flows
are stanched. Once the fish are removed, the
water clears enough for aquatic plants to
grow; the plants then help hold bottom sedi-
ments in place, even if the fish return.
The fish removal method is now used in
restoration projects around the world. And
the lake experiments helped generate enough
high-profile publications for Scheffer that,
in 1992, Utrecht University awarded him a
Ph.D., despite the fact that he never bothered
to formally enroll in graduate classes.
“Marten really formulated very clear,
testable theories about shallow lakes,” says
Stephen Carpenter, a limnologist at the University of Wisconsin, Madison, who studies
transitions in North American lakes.
To illustrate the findings, Scheffer introduced a type of graphic that has become a
hallmark of his work. It shows a ball rolling across a simple 2D hill-and-valley landscape (see p. 1554). A deep valley represents
a resilient, stable state, such as a clear lake
with plentiful vegetation and few nutrient
inputs. When the ball sits in such a valley,
it is difficult to move; if nudged, it quickly
rolls back to equilibrium on the valley floor.
But if a lake becomes overfertilized, the system resembles a valley with shallow slopes; a
slight nudge can push the ball into the next
valley—which represents a new stable state
like a turbid lake. Restoring clarity means
finding ways to lower the hill and reverse the
ball’s path—such as cutting off nutrients and
removing bottom fish.
Such graphics have been invaluable in
communicating Scheffer’s ideas to policy-makers and field workers, who don’t typically dabble in complex mathematics. “The
ball in a cup pictures really helped get
the idea into the minds of managers, and
now they’re using it all the time,” he says.
Scheffer “really bridged the gap between the
deep theory and the application,” Mooij says.
“He was very effective in communicating this
for both scientific and applied audiences.” (In
contrast, Dalí’s 1983 effort to depict tipping
point theory met with less success; the paint-ing, part of his “Catastrophe Series,” was his
last and is little known.)
SCHEFFER’S CAREER has had its tipping
points, each carrying him further from his
home in limnology. In the mid-1990s, his
lake work helped persuade the more senior
Carpenter to invite Scheffer to join the Resilience Alliance, an eclectic confederation of
scientists who study what makes some systems stable in the face of change. Scheffer
recalls that at his first meeting, in 1997 in
the bush in Zimbabwe, the group sat around
nightly campfires, trading ideas. “It was very
inspiring,” he says.
Four years later, he and a group that in-
cluded several participants in the Zimbabwe
retreat published a Nature paper that aimed
to bring the concept of ecological tipping
Before diving into
science, Marten Scheffer
studied music. He’s
recorded 15 albums.