Page 620 - The British Big Four

owever, in the face of other human- reefs by cutting off their sunlight. Trash also M ining also destroys coral. Sometimes
kills coral reef animals. Floating trash can coral pieces are removed for use as
H induced pressures, corals have become cover reefs, blocking off sunlight that pol-

vulnerable. In many cases, bleached coral

colonies die. In the past few decades, the yps need to survive. Turtles often mistake bricks or road-fill. Or, sand and limestone

amount of carbon dioxide in the air has in- plastic bags for jellyfish and eat them. Plas- from coral reefs are made into cement for

creased by one-third. This is harmful to cor- tic blocks the turtle’s digestive tract, causing new buildings. But corals aren’t only re-

als because increased amounts of carbon them to starve to death. Lost or discarded moved from their habitat for construction;

dioxide are dissolving into the water, which fishing nets - called “ghost nets” - can snag they are also sold as souvenirs. Coral curios

appears to be dissolving the skeletons of on reefs and strangle thousands of fish, sea and jewelry are often sold to tourists and ex-

corals. As a result, coral in waters with large turtles and marine mammals. porters in the markets of developing coun-

amounts of carbon dioxide form weaker C onstruction along coasts, inshore con- tries.
skeletons, making them more vulnerable to struction, mining, logging and farming
damage from waves, careless tourists, and along coastal rivers can all lead to erosion. T ourist resorts that empty their sew-
destructive fishers. age directly into the water surrounding

S cientists have identified pollution as one As a result, particles end up in the ocean coral reefs contribute to coral reef degra-
of the leading causes of coral reef degra- and cover coral reefs. This ‘smothers’ coral dation. Wastes kept in poorly maintained
and deprives it of the light it needs to sur- septic tanks can also leak into surrounding

dation. This threat comes from a variety of vive. Mangrove trees and sea grasses, which ground water, eventually seeping out to

sources. For example, oil, gas and pesticide normally act as filters for sediment, are also the reefs. Careless boating, diving, snorke-

contamination poisons coral and marine life. being rapidly destroyed. This has led to an ling and fishing can also damage coral reefs.

Reefs are harmed when human, animal waste increase in the amount of sediment reach- Whenever people grab, kick, walk on, or

and/or fertilizer is dumped into the ocean or ing coral reefs. Mangrove forests are often stir up sediment in the reefs, they contrib-

when river systems carry these pollutants to cut for firewood or removed to create open ute to coral reef destruction. Corals are also

reef waters. These pollutants increase the beaches. They are also destroyed by prawn harmed or killed when people drop anchors

level of nitrogen around coral reefs, caus- harvesters to open up areas to create artifi- on them or when people collect coral.

ing an overgrowth of algae, which smothers cial prawn farms.