Coral reefs are one of the major attractions
for divers around the world. But they are also the most biologically diverse marine eco-systems on
earth, rivalled only by the tropical rainforests on land. Corals grow over geologic time and have been
in existence about 200 million years. Coral reefs are believed to contain the highest concentration of
unique species in the ocean. Covering just 0.17% of the sea floor, they are home to an estimated
25% of the marine species. Corals reached their current level of diversity 50 million years ago.
The delicately balanced marine environment of the coral reef relies on the interaction of hard and
soft corals, sponges, anemones, snails, rays, crabs, lobsters, turtles, dolphins and other sea life.
A coral reef is composed of thin plates or layers of calcium carbonate secreted over thousands of
years by billions of tiny soft bodied animals called coral polyps. It takes years for some corals to
grow an inch and they range in size from a pinhead to a foot in length. Each polyp excretes a
calcereous exo-skeleton and lives in a symbiotic relationship with a host algae, zooxanthellae, that
gives the coral its color. Zooxanthellae takes in carbon dioxide, process is through photosynthesis,
and then gives off oxygen as a by-product that is used by the host polyp. There are two types of
stresses associated with reef systems: Natural and human-induced. However, reefs show a surprising
adaptation to short-term natural catastrophic events, such as hurricanes. But reefs are not well
adapted to survive exposure to long term stress, which is typical for stress cause by human wast.
Some examples include agricultural and industrial runoff, increased sedimentation from land clearing,
human sewage and toxic discharges. Just like the rainforests, the reefs are a source of immeasurable
biological wealth, which already is of utmost importance in the research for new drugs against all
sorts of diseases and sicknesses. No chemical laboratory comes even close to these natural drugstores.
But when the rainforests and the coral reefs disappear, so will an immeasurable treasure for humanity
and nature. Of the 110 countries with coral reefs, the reefs of 93 are in decline. It is estimated that
approximately 10% of coral reefs worldwide have now been destroyed. Based upon current trends,
60% could be gone within the next 20-40 years. |
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As divers, snorkelers and tourists in general, we have the most
direct impact on coral reefs. Some of us are loving coral reefs to death, others simply treat them as a piece of rock. The easy accessibility
and beauty of the Florida Keys' coral reef ecosystem, for example, brings well over one million scuba divers, snorkelers, fishermen and boaters
to the Keys each year. This is approximately 10 times the number of tourists as the Great Barrier Coral Reef of Australia, which is ten times larger the
Florida's reef. Many of these people do not even have a basic understanding of the coral reef ecosystem. Snorkelers knock of corals with their
feet or touch them with their hands and equipment, with often deadly consequences for the corals. Divers hold on to the coral banks to get in
position for the perfect shot, killing what they have banned on film in the process. Fishermen are ripping off pieces of corals with their lines.
Beach-goers walk around on corals with their shoes on so they don't get cut by the nasty "rocks" and boaters throw out their garbage and pour
out their sewage over coral reefs, endangering also the other inhabitants. Turtles, for example, often die after having divulged plastic bags swimming
in the water, because they mistake them for jellyfish, one of their main staple. But there are also people breaking off corals on purpose in order to
collect them for their fish tanks at home or to sell them on the market as souvenirs. |
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| What you can do:
When you go diving, be prepared to get around without pulling yourself along the coral bank to get to your destination.
Speak up when someone in your group behaves unproperly, can't control his or her buoyancy, touches or removes corals, etc. Ask the dive
guide to either help these people or exclude them from further trips. Take all your garbage back to shore and recycle whatever you can. Explain
to your friends and fellow tourists what corals are and why they are important. Pass up fishing and racy boat trips altogether.
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Indirect human impact mainly affects the coral reef ecosystem in the form of
runoff from our civilisation, for example by way of excessive amounts of nutrients (nitrates and phosphates), pollutants and pathogens (disease carrying
organisms). Nitrates and phosphates come from sewage disposal be it from boats or canals, from fertilizers or cleaning products, to name a few. These
nutrients stimulate the growth of algae, which then competes with corals for space and oxygen. Algea also reduce water clarity which inhibits the
photosynthesis by zooxanthellae, thereby decreasing skeleton production, the home for the tiny polyps living in the corals. Pollutants such as heavy metals,
oils, engine exhaust, herbicides, pesticides, DDT and PCBs and toxic waste dumping directly affect the corals and kill them off. Last but not least,
pathogens reaching the ocean directly kill off corals and other marine life. But there is also solid waste disposal which could affect coral reefs, for
example by continuously rubbing against the polyps slowly killling them off. |
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| What you can do:
Make sure the products you buy and use are low on ingredients which could affect the ocean (where much of it lands in the end)
over excessively. Bring all your garbage back to shore, and don't be too busy or too proud to pick up an extra bit lying around. If you see somebody
abusing the ocean as his personal dumpsite, pee on his car and try to explain the relation between his and your dumpsite to him. Wear a bullet-proof
vest if you are in America. |
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Siltation and Sedimentation are additional human induced threats to coral
reefs around the world. Much of the bottom around shallow coral reefs consists of fine silt. Boats running over shallow waters which disturb and
suspend silts with propellers and snorkelers and divers kicking up silt with their fins cause the water to turn murky permanently and thus inhibit photo
synthesis by seagrasses and algea inside corals. Heavy sedimentation may even bury whole coral grounds, inhibiting their growth and killing them off.
Causes for such sedimentation include development and beach renourishment (bringing sand back to beaches which was washed away). Agricultural
sedimentation, construction of seawalls, canals, docks, and marinas, land-clearing, destruction of mangrove woods and coastal areas in general, boats
running over shallow waters etc. |
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| What you can do:
Behave like a decent diver, control yourself and leave no traces. When you can't see the fish anymore for
all your kicking with your fins, then you are definitely in need of a thorough retraining. |
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A bad example for construction at the cost of the coral reef
ecosystem is the erection of a huge pier next to the Paradise Reef in Cozumel (read our report on the Cozumel page). Once a thriving
coral reef and popular dive site, this area in Mexico still faces a major threat: the construction of a cruise ship. Construction of this large cruise
ship pier is close to completion and will double the number of cruise ships stopping at the island and could cause serious harm to Paradise
Reef from sedimentation, bilge, chemical waste, and other pollution. And all this in spite of a referendum held in Cozumel last year which
showed that over sixty percent of local residents opposed building the pier. Several other proposed pier sites in Cozumel-
acceptable to the cruise lines, divers, and the local community- were rejected by the Grupo Consortio H developers because
of their private financial interests. The developer's "environmental" program to glue chunks of the reef onto concrete blocks in
other locations is a farce that will do nothing to save the reef. So far, the Mexican government says that it has no plans to halt the construction
of the pier. But thanks to the efforts of environmental groups around the world, pier construction is currently 7 years behind schedule,
and the reef has not yet been destroyed. |
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| What you can do:
Support letter writing campaigns to the Mexican government and protest against this form of
development. Tell them that you want ecologically sound forms of tourism and that you reject such destructive
construction practices. |
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Cyanide fishing, believe it or not, is a practice widely used
to catch live fish. Cyanide, one of the most toxic poisons known, is being used to catch live fish in the South Pacific and Southeast Asia.
Fishermen stun fish by squirting cyanide into the reef areas where these fish seek refuge. They then rip apart the reefs with crowbars
to capture disoriented fish. But cyanide is also a killer of coral polyps and the symbiotic algae and other small organisms necessary for healthy
reefs. This criminal practice is widespread, highly profitable, and causes massive destruction to coral reefs. And it is on the increase. Whereas
cyanide fishing was formerly used to catch exotic fish for aquariums, the increasing demand for life fish in restaurants in (yes, you guessed it!!!)
Hong Kong and other Asian centers is driving this devastating practice. Each year, an estimated 330,000 pounds of cyanide is sprayed on
Philippine coral reefs alone. Cyanide fishing operations are moving from the over-harvested and devastated reefs of the Philippines to destroy
remote and pristine coral reefs in eastern Indonesia, Papau New Guinea, Palau, Tuvalu, the Federated States of Micronesia, and other nations
in the Western Pacific. The reason are simple live fish sells for a price many times higher than dead fish. While cyanide fishing is illegal in most
nations, many governments do not monitor and enforce restrictions against cyanide use (there's another surprise). |
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| What you can do:
One may hope that the cyanide hasn't worn off when the fish reaches the table. Boycott countries which allow cyanide fishing
and write to their governments. Tell them that you wanted to visit, but changed your mind. |
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For a day and a half in last October, Mitch, the biggest hurrican in the Caribbean in over a hundred years, has hit the
Bay islands of Honduras, a popular destination for American divers. Six months later, it seems that the coral reefs have stood up to the
challenge pretty well. Mitch had made only a few new dents - and almost none below 20 feet. Damage detected was mostly contained to
small pockets. On the other hand, it is depressing to reflect on the probability, that a strom the size of mitch, 350 miles wide, with heavy
wind gusts at an incredible 280 mph and 25-foot waves, pounding the Bay islands for almost forty hours, would do less damage to the
reefs than carless divers and the kings and queens of buoyancy-ineptitude. |
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