|
 Aquatic EcosystemsToxic Chemicals: Page 5 Pollution-caused mortality of wildlife was, until recently, rare, occurring in isolated areas in the world's oceans. Increasingly, however, these poisons are becoming widespread, and the effects on ecosystems and individual species have been serious. Red tides have affected the Chinese coast in recent years, causing massive fish kills and wiping out fish farms (Chu 2000). They are attributed to sewage dumping. In Hong Kong, where a red tide covered 2,000 square miles, 700,000 tons of sewage is dumped yearly into the nearby Bohai Sea (Chu 2000). Long-term dumping of sewage, toxic chemicals and fertilizer is killing all fish and sea life, creating "dead zones." A dead zone in the Gulf of Mexico off the delta of the Mississippi River covers 7,000 square miles, the size of New Jersey; it spreads west to the Texas coast (Yoon 1998). Caused by a lack of oxygen, 50 dead zones were found in oceans and seas throughout the world by 2000. Cruise ships now number in the thousands, and each one generates a million gallons of waste water, 200,000 gallons of sewage and 25,000 gallons of oil-contaminated water each week, according to the Bluewater Network (Johnston 2000). Even small motor boats are heavy polluters of the air and water, emitting toxic fumes and leaving trails of oil and gasoline in the water.
|
|
