Page 41 - Coral Reef Teachers Guide
P. 41
Coral Reef Teacher’s Guide Benefits, Threats, and Solutions
asthma, herpes, and even broken bones are forests, wetlands and savannas, coral reef
being dis- covered in coral reef ecosystems ecosystems are integral parts of a healthy
around the world. For example, compounds environment for all of the Earth’s living crea-
derived from Caribbean sponges are being used tures, including people.
in the treatment of cancer and herpes simplex Threats
(Figure 3-2). Compounds from sea squirts have
been useful in treating tumors, viruses, and im- Corals are highly sensitive to environmen-
mune- related illnesses. Hard corals are being tal condi- tions. They grow best in shallow,
used to replace shattered bones as the human clear water between 68˚F and 84˚F (20˚C and
body more readily accepts coral than artificial 29˚C) with normal oceanic salinity. Both nat-
replacements. ural and human-caused (anthropo‐ genic)
Many commercial products are also derived disasters threaten coral reefs worldwide.
from coral reefs. Calcium carbonate from the In 1997, the International Year of the Reef,
skeletons of coral animals is used to produce it was rec- ognized that corals around the
lime which when added to mortar and cement world are threatened:
helps it set more quickly. The internal shell • In the Philippines, about 70% of the coral
of the cuttlefish, called cuttlebone, is sold in reefs have been degraded seriously and only
pet stores to cut calcium deficiency in the diet about 5% are thought to be in good condi-
of pet birds. Chitin, derived from the shells of tion;
shellfish, crab, lobster, and shrimp, is a com-
ponent of chitosan, which is used in violin var- • In Jakarta Bay, Indonesia, human activi-
nish to make it dry hard to provide good tone. ties have caused the average coral coverage
Much can be learned from reefs about histori- to diminish from 30% to 5% between 1985
cal conditions in the marine environment. An- and 1995;
nual growth bands, elemental ratios, and iso- • In Jamaica, where the coral coverage was
topic signatures can be used to infer past sea 50% to 70%, overfishing has accounted for a
levels, growing conditions, the effects of envi- decline of coral coverage to just 5%;
ronmental management and other important
phenomena. The beautiful sand that makes up • In the Florida Keys, coral diseases, mas-
the beaches of tropical islands is another ben- sive algal
efit from coral reefs, formed by the breakdown
of dead corals and algae by reef life. Like rain-
blooms, and a precipitous
drop in water visibility on
the world’s 3rd largest bar-
rier reef reflects the damage
from agricultural runoff from
Florida Bay and inadequate
sewage treatment throughout
the Keys.
• Conservative estimates
indi- cate that up to 10% of
the Earth’s coral reefs are al-
ready seriously degraded and
a much larger percentage is
threatened by the impact of
human activities;
• At the current rate of de-
struc- tion,estimates indicate
that 40% of the world’s reefs
could be destroyed by the
year 2020.
Figure 3-3. White band disease at the bottom of a plate coral. (Photo: Jim While natural impacts such
Thompson) as hurricanes and population
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