Register Log in  Scientific Method / Science & Exploration
Chemical warfare on the reef  Algae kill corals, corals muster
fish, fish eat algae and become more toxic.  A goby eyes up some
algae that's intruding on its coral home. Danielle Dixson   At
the root of these communications is a competition between corals
and an algae called Chlorodesmis fastigiata. In the wild, the
algae can start growing on reefs, where it is able to send a
simple message to nearby coral: die. Various studies have
indicated that the algae can carry coral disease and create an
oxygen-depleted environment that's harmful to corals. Within
three days of researchers placing the algae on a coral, the
coral's photosynthetic activity dropped by about 80 percent.
With the corals gone, the algae can then occupy the reef.  But,
as researchers found, corals can fight back. Simply placing an
extract of the seaweed near the coral caused it to emit its own
message: come help me! The recipients of this message? Fish
called gobies. Pairs of these f