June 2012 ISSN 2070-4593 - NGC

Caribbean Wins the Seaweed Olympics
A new study finds that Caribbean seaweeds are far better competitors than their
equivalents in the Indian and Pacific Oceans. But this triumph is bad news for
Caribbean coral reefs.
The picture-postcard beauty of Caribbean reefs owes much to the living corals
that build reefs and contribute startling white sand to beaches. Coral reefs might
seem to be tranquil environment but in fact a battle is constantly waged between
corals and seaweeds that fight over space.
Scientists have known for some time that seaweeds can gain the upper hand
if corals are damaged by hurricanes or excessively warm sea temperatures that
cause coral bleaching. But a new study, published online in early June, reveals
that Caribbean seaweeds are the equivalent of Olympian athletes compared those
found on coral reefs elsewhere.
“Seaweeds bloom four times faster in the Caribbean than the Pacific Ocean,”
exclaims study author, Dr George Roff, of the University of Queensland. “This helps
explain why corals in the Caribbean seem to be such weak competitors against
seaweeds.”
The study raises concerns about the future of Caribbean coral reefs. If seaweeds
bloom faster, corals are less likely to recover once they have been damaged.
Co-author, Professor Peter Mumby, adds, “Seaweeds are able to bloom when
we loosen their controls, either by polluting the sea with fertilizers or catching too
many parrotfish, who treat seaweed as a delicacy. We now know that seaweeds
will bloom if we give them the slightest chance. This means we should redouble
our efforts to control pollution and fishing of parrotfishes.”
The study, published in the journal Trends in Ecology and Evolution, cannot yet
explain why Caribbean seaweeds are so prolific.
“It is intriguing to see such variability in seaweed behavior around the world,”
says Dr Roff. “We raise a number of possible explanations that scientists will test
over the next few years.”
June 2012 Earth Conscious