Marine Pollution

Marine Pollution

For most of human history people relied on the “Dilution Philosophy”. This is the mistaken notion that the oceans are so vast that no matter how much ‘stuff’ we dump into them, and no matter what that ‘stuff’ might be, the substances will be so diluted that they will not cause any harm. For most of human history, when populations were small and industrialization had not yet introduced mass-production, this idea seemed to work. And of course since no one was looking for the harm caused by pollution, none was found.

If there was a single turning point it may have been in June of 1962 when Silent Spring was published in three parts in The New Yorker magazine. The book was released in September of the same year. Silent Spring quickly became a NY Times best seller and was the first widely read account of damage to the environment resulting from human activity.

Silent Spring documented the effects of the pesticide DDT on the brown pelican. Brown Pelican populations had been decreasing and no one knew why. Studies revealed that the birds were laying eggs with paper-thin shells which broke as soon as a bird sat on them. Further investigation revealed extremely high levels of DDT in the birds them- selves.

It was easy to establish that DDT interfered with shell production, but what was less obvious was why there were high levels of DDT in the birds when ocean water levels of the pesticide were extremely low. The answer is bio- magnification, shown here with an osprey at the top of the food chain. The same principle applies to pelicans or any animal, including humans, at the top.

But how did the DDT get into the ocean? Agricultural runoff: DDT was sprayed on crops to kill pests and improve crop yields. With every rain some of the chemical was washed into the ground where it found its way to streams, and rivers and eventually to the sea. Silent Spring was published in 1962. It took 10 years but eventually the use of the pesticide was banned. The brown pelican and other fish-eating birds (ospreys and bald eagles) have made a remarkable comeback.

It is almost certain that there are small amounts of DDT in your body right now. How did it get there? DDT residues in the soil where the plants you eat are grown. DDT in the feed of the animals you eat. DDT in the ground water you drink. DDT in fish which become fish meal which is added to animal feed. But most important, one person can make an enormous difference. Thanks to Rachael Carson a great threat to the environment has been reversed.

Pollution of the marine environment comes in many forms which have one thing in common: HARM to the environment. Forms of ocean pollution include.............. > Garbage dumping > Acidification > Eutrophication > Plastics including nurdles and microbeads > Noise, aka sound pollution > Silt and dust from farms, deserts, and construction > Issues caused by deep sea mining > Release of methane from clathrates

For almost all of human history garbage has been dumped into rivers or directly into the sea. Sometimes it was burned first. Sometimes the raw garbage was dumped. New York City provides a case in point: Until the 1880’s 75% of NYC garbage was dumped directly into the Atlantic Ocean. Later some waste was buried in land fills and the rest was burned in incinerators. The ash was dumped at sea.

Dumping of garbage and ash creates ‘dead zones’ in the oceans (see red circles on the map). There is virtually no life in these regions.

All of the laws (above) were intended to ban ocean dumping, provide for monitoring of the environment, and improving the quality of water.

Much marine pollution came from the thousands of ships that cross the seas each year. Ships discharge: Fuel oil Human wastes Bilge water, Water from ballast tanks, Water used to flush out cargo holds and tanks. Water from ships laundries Solid wastes from all ship operations

Since there are thousands of ships of all kinds constantly crossing the seas they account for a great deal of marine pollution. Recent laws and treaties severely restrict this kind of pollution, however some shipping lines circumvent these regulations by registering their ships in countries that have not signed the treaties and do not enforce these laws.

Eutrophication: A process in which an ecosystem is damaged as a result of the introduction of plant nutrients such as nitrates and/or phosphates. Most plants need minerals which they usually get from the ground or from the water. The most important of the minerals are nitrates and phosphates.

Usually it is the amount of these minerals available that limits plant growth. When farmers fertilize their fields they are adding these minerals. This increases crop yields.

But sometimes we add these same fertilizing minerals to bodies of water even though we never intended to. Sewage discharge contains large amounts of nitrates from human waste. It also contains large amounts of phosphates from all the detergents we use to clean dishes, laundry, and other items.

Another major source of nitrates and phosphates is runoff from farms, golf courses, and lawns. Adding fertilizer to bodies of water causes algae to grow at a very rapid rate.

The more algae that grow, the more algae die, and when they die they sink to the bottom forming a thick layer of dead plant material. This is welcome news for the bacteria in the water which break down the plant material in a process called decay.

Of course more dead plant material for the bacteria to ‘eat’ means more bacteria. Since these bacteria are aerobic they quickly use up all the oxygen in the water. Without dissolved oxygen in the water the fish, frogs, insects larvae, and all other aerobic life forms vanish.

The only thing left is a body of water covered in a thick layer of green slime.

Quick recap: 1) Add fertilizer (sewage) to a body of water. 2) More and more algae grow. 3) More algae growing means more algae dying. 4) Dead algae are food for aerobic bacteria living in the water so soon there are more bacteria. 5) Bacteria deplete the oxygen in the water, 6) With the oxygen gone all the aerobic organisms, the fish, amphibians, and insect living in the water die. 7) What’s left is a lifeless, slime covered body of water.

Plastics: The problem is simple..... We dump thousands of tons of plastic in the oceans. Almost none of it is biodegradable. It lasts forever. Ocean currents called gyres concentrate the floating plastic garbage into two large areas of the ocean.

Marine organisms, including birds, fish, turtles, and mammals such as whales and dolphins eat the plastic. Since it cannot be digested it clogs their digestive systems leading to slow death by starvation or worse, slow and painful death due to intestinal blockage. Above, the rotting carcass of a pelican reveals what killed it: A lighter, a plastic bottle cap, a prescription pill vial and other assorted bits and pieces.

Many plastics release chemical into the water. Some of these are toxic while others don’t kill directly but interfere with the reproductive cycles of marine organisms. Much attention has been given to BHA, a chemical now banned from use in food containers in the US and in Europe. Still, millions of tons of plastics containing BHA are already in the oceans and are releasing the chemical into the water.

The two primary sources of plastics are ocean dumping of municipal waste (from cities) and dumping from ships. As usual, attempts to regulate both sources by laws and treaties are limited because so many countries fail to sign treaties or to enforce laws.

In recent years many products have been made with plastic micro beads which act as abrasives to smooth skin. More and more of these particles have been appearing in the Great Lakes and will make their way to the oceans.

The micro beads create two problems................ First, they enter the food chain and interfere with normal digestion. Second, toxic chemicals in the water adhere to the surface of the beads. When the beads are ingested by marine organisms the toxins enter their bodies. In other words, the beads become a delivery system to get toxins into marine life. Some manufactures have already agreed to stop using the beads in their products.

Anthropogenic Ocean Noise Pollution: ‘Anthropogenic’: Man-made ‘Noise Pollution’: Sounds which cause harm

Sources of noise pollution: • Low frequency active sonar used for echo-location • or locating other ships. • Seismic surveys using air gun arrays (similar to • sonar but much more intense). • Noise from ship propellers and on-board machinery. • Noise from drilling platforms What harm is caused by noise pollution?

Many marine creatures use echo location to find • food. Loud underwater noises interfere with • normal feeding. 2) Noise may drive fish and other species away from places where food is abundant to other, less desirable feeding grounds. 3) Studies have documented hearing loss in many species of fish. 4) Some marine organisms use sound to attract mates. Noise can interfere with normal reproductive activities.

5) Fish, frightened by alien noises, have shown symptoms including.................................. Mutated offspring Internal hemorrhaging Higher mortality rates Stranding (beachings) of whales and dolphins

There will be two bonus questions on the test based on the following 3 slides.

Oil pollution from spills, runoff from the land, and from ships at sea. The two best known oil spills are the Exxon Valdez spill in March of 1989 and the BP spill in the Gulf of Mexico in 2010

But there have been many other catastrophic oil spills. Here are just a few. 1) The Torrey Canyon Oil Spill, March 18, 1967Where: Scilly Isles, UKAmount spilled: 25-36 million gallons 2) The Sea Star Oil Spill, Dec. 19, 1972 Where: Gulf of OmanAmount spilled: 35.3 million gallons 3) Arabian Gulf/Kuwait, Jan. 19, 1991 Where: Persian Gulf, KuwaitAmount spilled: 380-520 million gallons Intentional – spilled by Iraq forces to prevent American troops from landing in Kuwait.

4) Atlantic Empress Oil Spill, July 19, 1979 Where: Off the coast of Trinidad and TobagoAmount spilled: 90 million gallons 5) Ixtoc 1 Oil Spill, June 3, 1979 Where: Bay of Campeche off Ciudad del Carmen, MexicoAmount spilled: 140 million gallons

Marine Pollution