Subject:  CORAL REEFS DECLINE- NEED FOR FURTHER STUDY IMMEDIATELY

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SCIENTISTS URGE FURTHER STUDY OF ALARMING CORAL REEF DECLINE

     Scientists are becoming increasingly concerned about the
mysterious decline of coral reefs throughout the world and are
recommending more extensive research into the potentially serious
problem.
     The corals are at the center of a complex food web.  When they
die, thousands of other species are in jeopardy.  People in some
developing nations are dependant on the coral reef communities for
their food or livelihoods.  Corals also contain toxins that offer
promise for cancer research and chemical compounds that could be
used to make new medicines.  "But we are just in the infancy of
doing those kinds of studies," said Johns Hopkins University
biologist Gary K.  Ostrander.  Ostrander co-authored a scientific
paper about the worldwide threat with biologist William J.  Meehan,
a doctoral student in his laboratory.
     The paper, essentially an overview of declining coral reef
health, will be published on April 25 in the Journal of Toxicology
and Environmental Health.
     "We are pointing out that these corals are dying all over the
world," Ostrander said.  Scientists do not know what is causing the
coral reef deterioration, which has accelerated dramatically since
the early 1980s.  But their deaths may signal serious, as-yet
unidentified environmental ills, said Ostrander, who noted in the
paper that there have been few studies to detail the phenomenon at
the molecular and cellular levels.  Also lacking are studies aimed
at uncovering possible environmental causes.
     "We believe our ability to understand and possibly remedy this
complex global problem will be accelerated as toxicologists begin
to address these issues," the two biologists concluded in their
paper.
     Corals, like jellyfish and sea anemones, belong to the phylum
Cnidaria.  They are tiny animals that use their tentacles to catch
food particles floating in the water.  Certain types of corals
produce calcium carbonate skeletons -- the coral reefs.  Once
attached to the chalky white skeleton, the tiny animals are called
polyps.
     The corals provide critical habitats for a multitude of other
aquatic animals, and many of those animals serve vital symbiotic
relationships, making up a complicated and fragile web.  The mostimportant of
those symbiotic organisms is a single-celled,
photosynthetic algae called zooxanthellae, which take up residence
inside the clear tissue of the polyps, coloring them with various
pigments.  The algae collect sunlight, providing energy and
nutrients for the corals.  The corals, in turn, provide protection
for the algae.
     One of the most disturbing problems afflicting coral reefs
throughout the world is referred to as "coral reef bleaching." For
unknown reasons, the algae have been evacuating corals at an
alarming rate.
     Without the pigmented algae, the white calcium carbonate
skeletons show through the clear polyps; the normally colored
corals appear bleached.  They then die, usually within a week or
two, Ostrander said.
     "We don't know what's causing the bleaching," he said.
"Furthermore, the bleaching represents only one of a variety of
processes contributing to the decline of coral reefs around the
world."
     Various diseases are ravaging the organisms, as well.  "When
you go to the Galapagos Islands, for example, 90 percent of the
corals are gone.  This is incredible."
     Theories to explain what is causing the decline in coral reef
health cover a wide range of possible natural and man-caused
scenarios.  Some scientists have implicated higher seawater
temperatures, presumably from global warming.  Other scientists
have found evidence for just the opposite, cooler than normal
seawater temperatures.  Still other theories blame pollution, oil
spills and sedimentation caused by construction and waste
discharge.
     Whatever the causes, the potential ecological and economic
consequences are ominous.  "There are literally thousands of
species of fishes that are associated with coral reefs, and they
feed off of the corals," Ostrander said.  "If they all start
disappearing, what's that going to do to the rest of the
ecosystem?" Coral reefs are an important factor in the economies
of many nations; for example, they provide key habitats for
lobsters and groupers.  The reefs also are a major tourist
attraction.  "You could imagine what Australia would be like if
people didn't have the barrier reefs to go to," Ostrander noted.
     The scientific paper discusses what is now known about the
worldwide decline of coral reefs and portions of the paper are
based on research that Ostrander and Meehan conducted while they
were at Oklahoma State University; Ostrander was a professor there,
and Meehan was a graduate student.  They have conducted most of
their studies on coral reef health in waters around San Salvador
island in the Bahamas.  It is one of 26 field stations in 16
nations where scientists have been using identical methods to
monitor coral bleaching and the decline of species diversity around
coral reefs.
     An example of the rapidly declining animal populations can be
seen in the shrinking number of sponges living on corals around San
Salvador island.  Within three years beginning in 1994, the number
of sponges observed by Ostrander and his colleagues declined by
about 50 percent.  "We now know that San Salvador is not unique and
that these sorts of trends are going on all around the world at the
same time," Ostrander said.
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