Paradise Lost
UMaine marine scientist warns of
global harm to fisheries with collapse of the world's coral reef
ecosystems
A
rise in the temperature
and acidity of the oceans that threatens the existence of the world's
coral reef ecosystems could also have troubling implications for marine
life and fishing industries as far away as Maine, a University of Maine
researcher says.
Robert Steneck, a
professor of marine sciences, is one of several authors of a new study
predicting that increasing concentrations of carbon dioxide in the
atmosphere, if not abated, will continue to deteriorate coral reefs to
the point where they are likely to disappear altogether in the next few
decades.
The potential collapse
of these most biologically diverse and economically important ecosystems
suggests a global atmospheric crisis that, Steneck says, could seriously
harm fisheries worldwide.
"The Carbon Crisis:
Coral Reefs Under Rapid Climate Change and Ocean Acidification," which
represents the work of scientists from around the world, was published
in December in the journal Science.
"While we are far from
where coral reefs live, I think it's important to consider what this
might mean in Maine," says Steneck, who is based at UMaine's Darling
Marine Center in Walpole. "It's not as if coral reefs are on a different
planet with a different atmosphere. They may be the canary in the mine
shaft Earth, and the canary ain't doing so swell these days."
Scientists estimate
that 25 percent of the world's coral reefs are already gone or severely
damaged and that another third are degraded and threatened. Rapid
increases in carbon dioxide emissions, which in the 20th century have
raised the average temperature of the world's oceans by more than 1
degree Fahrenheit, "may be the final insult to these ecosystems," the
study states.
The acidity caused when carbon dioxide
and water combine to make carbonic acid reduces the availability of
calcium carbonate, or limestone, in the sea. Coral reefs are made of
limestone, and lobsters, sea urchins, clams and scallops need it to
calcify the hard parts of their bodies. Pteropods, a small, swimming
organism with shells inside their bodies, are a major food source for
Atlantic salmon. Yet, Steneck says, there is evidence that their shells,
which the organisms can't live without, are already eroding.
Reduced carbonates in
the world's oceans are forcing marine creatures to spend more energy
making their shells, which places them under greater stress. According
to Steneck, about 30 new stress-induced coral diseases have been
identified in the last decade.
"And in Maine,
anything that stresses shell-producers makes them more susceptible to
disease," he says. "In Rhode Island in 1998,there was a large-scale
die-off of lobsters. If the same thing happened in Maine, where lobsters
represent 85 percent of all marine resource value, it would threaten the
socioeconomic fabric along the entire coast."
While some marine
organisms have shown they can adapt to warmer temperatures, Steneck
says, the projected increases in carbon dioxide buildup and temperature
will overwhelm that ability in the decades to come.
Steneck, who does
fieldwork in Central America and Mexico, is part of an international
science program called Coral Reef Targeted Research. Funded by the
Global Environmental Facility and the World Bank, the partnership of 40
research institutes seeks to reduce global poverty in developing
countries that depend on coral reefs for fishing, tourism and coastal
protection.
"We do have a global
atmospheric crisis and we have to work on a global level to change it,"
Steneck says. "The point is not to be alarmist, but rather to say that
we have to redouble our efforts to curb emissions. We need to generate
more political will to do it."
Because eliminating
emissions won't happen overnight, Steneck urges the fishing industries
in Maine and elsewhere to manage themselves with greater sensitivity to
the health of the ecosystems that sustain them.
"The trajectory of a
planet that is getting rapidly warmer and more acidic will likely affect
organisms globally," he cautions. "The problem is in our backyard."
by
Tom Weber
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