Amazing colors and shapes and thousands of fishes make coral reefs
one of the most spectacular underwater places for people to visit.
Each reef is completely unique in its shape and the kinds of animals
that call it home. A great number of plants and animals that live
in coral reefs have not been studied, or even named, yet. Some of
the ones we are studying may give us new medicines to treat cancer,
protection from too much sunlight and antibiotics to fight infections.
Erosion does not affect coral directly, but silt, mud, fertilizers
and herbicides that wash off the surrounding land damage delicate
coral reefs. Silt and mud cover the corals with a cloud of haze,
and herbicides kill not only the algae that live within coral polyps, but plant life all over a reef. Fertilizers
and untreated sewage provide an excess of nutrients where certain
types of algae will grow faster than
they normally would.
The overgrown algae choke the coral reefs and attract predators, such as sea urchins
and crown-of-thorn starfish, which destroy living coral. A major
problem in coral reefs around the world is coral bleaching. algae that live inside the polyps and gives them their brilliant colors
is killed or ejected. When this happens, an entire coral reef
can turn white. Scientists are still not sure exactly what causes
this to happen. One theory suggests that coral bleaching is the
result of higher than normal water temperatures.
Oil Tanker Spill
Humans have done a great deal of damage to coral
reefs around the world. Oil spills and pollution suffocate living
corals and poison the waters. It can take many years for a reef
community to recover from the damage a single oil spill can do.
Tourism is another area where human impact has been harmful to reefs.
To attract tourists, some islanders have blasted boat channels through
reefs. Divers and snorklers damage or break fragile coral branches
by simply touching them or grazing them with a careless hand or
flipper. Dive boat operators and fishermen destroy reefs with anchors
and propeller blades. Souvenir-seeking tourists snag pieces of coral,
which took the reef years to build.