Download Coral Reefs: Critically Endangered

Coral Reefs: Critically Endangered
(c) James Watt, courtesy of NOAA/Dept of Commerce.
July 2008
Nearly three-quarters of the world’s reefs are gone or threatened.
“Rain Forests of the Sea”
Anchoring
a strong
web of life
in the sea,
coral reefs
protect us
in many
ways.
©2008 Ocean Conservancy
A decade ago, the world lost 16 percent of its coral reefs in one year. Had it been trees
instead and on one continent, the equivalent of nearly all the forests of North America
would have been wiped out … in a single year.
Coral reefs are nicknamed the “rain forests of the sea” for their amazing biodiversity and
productivity as well as their fragility and tremendous value to humans. They cover just
two-tenths of one percent of the ocean floor, yet may be home to a quarter of all of the
ocean’s species. Scientists have described some ten thousand coral reefs species, and
estimate that some three million may await identification. These promise an untapped
treasure chest of human benefits, including as yet undiscovered medicines.
But coral reefs are in deep trouble. In the Caribbean live coral cover has declined more
than 90 percent in recent decades. The loss of these critical ecosystems has significant
social, economic, and environmental impacts. Coral reefs provide jobs and food to
millions. In a 2004 survey of the world’s reefs, scientists found 20 percent of coral gone,
24 percent in imminent danger, and another quarter
under long-term threat. In other words, nearly threequarters of the world’s reefs are gone or threatened.
Anchoring a strong web of life in the sea, coral reefs
protect us in many ways – but they can’t protect us
unless they are strong and resilient. It is not too late to
turn the situation around – if we act now.
Threats
A number of human-caused activities are assaulting
coral reefs, causing their steep decline, and threatening
their future. From global warming to overfishing to
contaminants in the water, human actions are the direct
and indirect cause of coral reef mortality.
Coral reefs are like the canary in the mine when it comes
to global climate change and the ocean. We know that
ocean temperatures are near the maximum corals can
tolerate. Increases of just one or two degrees Celsius
can cause “bleaching” – a situation in which living coral
expels from its cells the symbiotic (good) algae it relies
on for life. The loss of these algae, which give coral its
color, exposes the coral’s white skeleton beneath. While
not immediately fatal, prolonged bleaching will weaken
or kill coral. As ocean temperatures rise, will corals
be able to adapt? Adaptation is unlikely if change is
too rapid. Scientists warn that three degrees of global
warming, a distinct possibility this century, could lead to
the death of most corals worldwide and the collapse of
their associated ecosystems, which will have devastating
consequences for coral-reef dependent communities.
Ocean acidification, also linked to climate change, further
threatens reefs. Because the ocean has absorbed 80
percent of the excess carbon dioxide humans have
generated, the water has become more acidic. This
acidification makes it more difficult for corals to build their
calcium carbonate skeletons. Many scientists now believe
that acidification is among the greatest long-term threats
to the ocean and that it will intensify as carbon levels in
the air and sea continues to rise.
Other threats abound. Chronic overfishing on reefs has
also thrown these delicate ecosystems out of balance,
removing predators and herbivores and allowing enemies
of reef health to invade. In the Caribbean, for example,
the result has been disastrous. The loss of plant-grazing
fish, coupled with a massive die-off of grazing sea urchins,
caused macroalgae to overrun the reefs, leading to a
precipitous decline in the abundance of corals. Another
threat, coastal development, flushes sediment into the
water, covering and smothering young corals. Chemical
fertilizers, animals waste, and sewage wash into the sea,
giving reef-choking algae a leg up.
What Ocean Conservancy is Doing to Help
Changing Policy: The key to saving coral reefs lies in
finding the balance between human activities and reef
health. First, we must respond to the global warming
threat through mitigation and adaptation. We must
reduce greenhouse gas emissions immediately. Ocean
Conservancy is informing the public via our website
and magazine. Our scientists and policy experts are
sharing their extensive expertise on Capitol Hill, and
urging policymakers to provide leadership on mitigation,
adaptation, and alternatives to carbon-based fuels.
Building Resiliency: Marine Protected Areas (MPAs), socalled “undersea Yosemites” where species can rebound
undisturbed by human activities, can restore the resiliency
of coral reefs. Our vision is to protect reef ecosystems
from human impacts as much as possible by establishing
more – and more protective – MPAs. There is evidence
that when left to their own devices coral reefs may
recover. The dire status of reefs dictates that we strive to
protect coral reef environments from damaging human
inputs – no more sediment, trash, or pollutants. And
that we take nothing out of MPAs– no fish, no oil and
gas, no minerals. Such “no take” MPAs, improved reef
management, and immediate action to mitigate global
warming are our best hope for the future of coral reefs.
Five Ways to Save Reefs
1. Join Ocean Conservancy: Your donation to Ocean
Conservancy gets multiplied when supporting the work
of our scientists and policy experts working to save reefs
and promote adaptation strategies in the face of climate
change. Join us at www.oceanconservancy.org.
2. Be a reef-friendly tourist: When visting a reef, respect
local guidelines and support reef-friendly businesses.
3. Champion Marine Protected Areas: MPAs give reefs
the chance to recover, so support the creation of more
and better “undersea Yosemites.”
4. Fight climate change: Reduce your own carbon
footprint, and urge elected officials to support mitigation
and adaptation strategies.
5. Use chemical pesticides and fertilizers carefully:
Even if you live thousands of miles from a coral reef,
they products can travel into your local waterways and
on to the ocean.
Visit Ocean Conservancy’s website for more
information on coral reefs and other ocean issues at:
www.oceanconservancy.org
Coral Reefs: Critically Endangered “Rain Forests of the Sea” • Page 2