Pollution and the Marine Environment. Pollution. The introduction by humans of substances, materials, or heat energy that decreases the quality of the environment. Oil. Crude oil or petroleum: refined to yield fuels and raw materials for plastics, synthetic fibers, rubber, and fertilizers.
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Pollution • The introduction by humans of substances, materials, or heat energy that decreases the quality of the environment.
Oil • Crude oil or petroleum: refined to yield fuels and raw materials for plastics, synthetic fibers, rubber, and fertilizers. • Most widespread pollutant in the ocean. • Biodegradable, slowly broken down by bacteria.
Sources • Tanker operations and wastes from cities. • Blowouts of offshore rigs, sinking or collision of supertankers. • In 1989, the Exxon Valdez spilled 35,000 tons of crude oil in Alaska. Millions of gallons
Effects on Marine Life • Sea birds and sea otters die of exposure when feathers or hair are coated with oil. They lose the ability to maintain the layer of warm air next to their skin to thermoregulate. • Valdez spill killed between 100,000-300,000 seabirds and 3500-5000 sea otters.
Solutions • Booms and skimmers can be used in calm seas. • Physically washing mammals and birds. • Double or triple-hulled tankers.
Economical Effects • Fish and shellfish become unmarketable. • Size of fish catches decreases. • Tourism decreases. • Cleanup costs money – Exxon was ordered to pay $5 billion in fines, $287 million to Alaskan fisherman, and $3.5 billion in cleanup costs!
Sewage • Domestic sewage: wastewater from homes, cities and buildings. • Industrial sewage: wastes from factories.
Types of Sewage • Raw sewage: untreated, discharged directly into the water. Carries viruses and bacteria that can become concentrated in shellfish. • Treated sewage: has been partially treated using chlorine to kill bacteria and some viruses. • Only 70% of U.S. population is served by sewage treatment plants.
Effects on Marine Life • Sludge smothers benthic communities. • Organic matter is decomposed by bacteria resulting in anaerobic conditions. • Number of species decreases, and those that survive often show abnormalities such as skin lesions and tumors. • Large amounts of nutrients overfertilize coastal waters = eutrophication. Blooms result, turbidity increases and light decreases.
Solutions • The Clean Water Act of 1972, reduces the amount of suspended solids in the discharged sewage. • Use marshes for natural sewage treatment. • Recycle sludge into landfill, building blocks or compost.
Mercury • Reaches the ocean through natural and human activities. • Used in antifouling paints, and to kill molds and bacteria, the production of chlorine, plastics, batteries, fluorescent lamps, etc. • Combines with other organic compounds to form methyl mercury, which accumulates in the food chain (high levels in tuna and swordfish). • Causes birth defects and nervous system damage in humans.
Lead, Cadmium & Copper • Concentrate in tissues of organisms. • Lead is found in paint and ceramics, and causes nervous system disorders and death in humans. • Cadmium and Copper are abundant where wastes from mining and dredging operations reach the sea.
Synthetic Chemicals Chlorinated hydrocarbons: • Pesticides such as DDT, aldrin and chlordane. • Used to control insects, and have saved millions from disease and starvation. • Enter ocean from wind, run-off, rivers and sewage. • Absorbed by plankton. • Non-biodegradable, and accumulate in tissues of organisms.
Effects on Marine Life • Most concentrated in carnivorous fishes, fish-eating birds, and marine mammals = biological magnification. • Fishes caught for human consumption had to be destroyed because they contained too much pesticide. • Marine and land birds could not deposit calcium in their eggshells so the shells broke before development was complete. This nearly caused the extinction of the Brown Pelican in the U.S.
PCB’S • Nonbiodegradable and persistent. • Poisonous chemicals used to cool machinery, and in manufacturing paints and plastics. • Caused cancer and birth defects. Effects on Marine Life: • Implicated in abnormal sexual behavior in seabirds. • Animals with PCB’s in their bodies sicken more easily.
Thermal Pollution • Seawater is used as a coolant in power plants, oil refineries and other industries. • This water is pumped into the sea where it is considered thermal pollution.
Effects on Marine Life • High temperatures adversely effect plants and animals, and decrease the amount of dissolved oxygen (D.O.). • Reef-building corals become bleached.
Solid Waste: Plastics • Flexible materials that can be molded or shaped into products from fast-food packages, CD’s, contact lenses, and surgical sutures. • Plastics are strong and non-biodegradable.
Effects on Marine Life • Entanglement in plastic lines, nets traps, and packing material. • Discarded fishing gear drifts and can continue to entrap marine life indefinitely= Ghost Fishing.
Effects on Marine Life • Ingestion of plastic bags or balloons may block the digestive tract causing death from starvation. • Many species of birds eat small plastic pellets they mistake for fish eggs.
Sustainable yield: the optimal annual catch that can be derived indefinitely from harvested species, without causing a stock failure. • 96 million metric tons of fishes, shellfish and algae are taken yearly by commercial fishermen. Almost 30% of this catch is never used for human consumption. • 100 million metric tons is the limit advised by United Nations Food and Agriculture Organization.
Herrings, cod, jacks, redfishes, mackerels, and tunas account for 2/3rds of the total annual catch. • 85% of species currently fished in American waters are now overexploited. • At least 14 species of fish have been so seriously depleted it may take 20 years to recover assuming all fishing were to stop.
Why Fish? • Over half the population of developing nations depends on fish as its primary source of dietary protein. • Fishing contributes to economic stability. (Recreational fishing = $50 billion a year and 600,000 full-time jobs!)
Who’s to Blame? • Sophisticated fishing devices, such as computers, radar and electronic depth finders allow fishing boats to locate large schools of fish with speed and accuracy. • TRAWLS and immense gill nets (40 ft long, 500 ft deep) sweep everything in their path including turtles, dolphins, sharks and sailfish. • Shrimp fishing…trawl mesh so small that for every 1 lb shrimp taken, 10 lbs of bycatchis caught.
Effects • Selectively fish out the larger, more desirable members of certain species. • Create inferior breeds, dominated by younger, smaller fish which mature and reproduce earlier, have fewer offspring, and have a shorter lifespan.
Lionfish Alien Species • Organisms that have been introduced into a new marine environment. • In their introduced environment, no natural predators exist. • Can restructure the food web, introduce diseases, and compete with and prey on native organisms. Caulerpa Zebra mussel
How Are Alien Species Introduced? • Ballast water - Large ships take on extra water into their ballast tanks to maintain stability in the open ocean. The water is then discharged in the new port, introducing new organisms. • Aquaculture – Species such as fish, shellfish and seaweeds raised in pens may escape or be released into local waters. • Seafood trade- Species purchased as seafood may be later dumped or released into local waters. These species can carry diseases, parasites and other organisms.
Whaling • The hunting of whales for commercial use and “research” purposes. • International Whaling Commission (IWC) governs the conduct of whaling throughout the world. • Countries that still conduct whaling include Japan, Iceland and Norway even though there is little market for whale meat.
Use less plastic Don’t use pesticides Dispose of hazardous materials properly Don’t buy products from endangered or threatened species Save Energy Recycle Plastics Recycle motor oil Recycle other forms of trash Don’t use sprays that contain CFC’s Get involved and keep informed 10 things we can do to save the Oceans: