20-4 What Are the Major Water Pollution Problems Affecting Oceans?

• Concept 20-4A The great majority of ocean pollution originates on land and includes oil and other toxic chemicals as well as solid waste, which threaten fish and wildlife and disrupt marine ecosystems.

• Concept 20-4B The key to protecting the oceans is to reduce the flow of pollution from land and air and from streams emptying into these waters.

Ocean Pollution Is a Growing and Poorly Understood Problem (1)

• Globally, since many people live near _____________ this area bears the brunt of our _________ of pollutants and wastes into the ocean

• 2006: State of the Marine Environment study conducted by UNEP…• 80% of marine pollution originates on ___________• 80-90% of municipal sewage from coastal LDCs is

dumped into oceans _____________ treatment• __________________ the coastal area’s ability to

breakdown biodegradable waste• Extra nutrients also causes excess ________________

coastlinesinput

land

withoutOverwhelm

algal growth

China’s Coastline Choked by Algae

http://www.theepochtimes.com

Ocean Pollution Is a Growing and Poorly Understood Problem (2)

• In deeper ocean waters, the ocean can ____________, disperse, and degrade large amounts of raw sewage and degradable pollutants

• Some scientist argue that it is ____________ to dump harmful waste into deep oceans rather than…• ______________ it on land• _____________ it in incinerators

• Others disagree since our knowledge of the deep ocean is ___________________ and this would delay pollution _______________ measures

dilute

safer

buryburn

limitedprevention

Ocean Pollution Is a Growing and Poorly Understood Problem (3)

• Cruise line pollution: what is being dumped?• ________________• ________________• ________________• Toxic __________________

• Such dumping is illegal in U.S. waters, but this is difficult to monitor

garbagesewage

waste oilchemicals

Ocean Pollution Is a Growing and Poorly Understood Problem (4)

• Recent studies of some U.S. coastal waters have found vast colonies of ____________ thriving in effluents from sewage treatment plants (which do not remove viruses)

• ______ of people using such waters have developed…• Ear infections• Sore throats• Eye irritations• Respiratory diseases• Gastrointestinal diseases

viruses

1/4

Fig. 20-16, p. 545

Industry Nitrogen oxides from autos and smokestacks, toxic chemicals, and heavy metals in effluents flow into bays and estuaries.

Cities Toxic metals and oil from streets and parking lots pollute waters; sewage adds nitrogen and phosphorus.

Urban sprawl Bacteria and viruses from sewers and septic tanks contaminate shellfish beds and close beaches; runoff of fertilizer from lawns adds nitrogen and phosphorus.

Construction sites Sediments are washed into waterways, choking fish and plants, clouding waters, and blocking sunlight.

Farms Runoff of pesticides, manure, and fertilizers adds toxins and excess nitrogen and phosphorus.

Red tides Excess nitrogen causes explosive growth of toxic microscopic algae, poisoning fish and marine mammals.

Closed shellfish beds

Closed beach

Oxygen-depleted zone

Toxic sediments Chemicals and toxic metals contaminate shellfish beds, kill spawning fish, and accumulate in the tissues of bottom feeders.

Oxygen-depleted zone Sedimentation and algae overgrowth reduce sunlight, kill beneficial sea grasses, use up oxygen, and degrade habitat.

Healthy zone Clear, oxygen-rich waters promote growth of plankton and sea grasses, and support fish.

Ocean Pollution Is a Growing and Poorly Understood Problem (5)

• Runoffs of sewage and agricultural wastes into coastal waters introduce large quantities of ___________ (NO3

-) and _______________ (PO43-)

• These are considered plant _____________, which cause explosive growths of harmful ______________.

• These harmful algal blooms (HABs) are called red, brown, or green __________ - can release waterborne and airborne toxins that…• poison seafood• Damage fisheries• Kill some fish-eating birds• Reduce tourism serc.carleton.edu

nitratephosphate

nutrientsalgae

tides

Science Focus: Oxygen Depletion in the Northern Gulf Of Mexico

• Excess nutrients can also lead to _______________ zones

• The world’s _________ largest oxygen-depleted zone forms every spring and summer in the Gulf of Mexico off of the mouth of the _______________ River

• Excess nutrients derived from the vast Mississippi River ____________ (watershed)• Highly productive farming area

oxygen-depleted

3rd

Mississippi

Basin

A Large Zone of Oxygen-Depleted Water in the Gulf of Mexico Due to Algal Blooms

Fig. 20-B, p. 546

A Large Zone of Oxygen-Depleted Water in the Gulf of Mexico Due to Algal Blooms

• Recall, that excess nutrients cause increased plant or algal ____________...as these organisms decompose, the DO levels in the area ___________.

• The low-oxygen levels ______________ fish, crabs, and shrimp that cannot move out of the area

• Possible tipping point? Solutions?• Use ________ fertilizer• Use techniques to reduce soil _______________• ________________ sewage treatment plants • Lower emissions of nitrogen oxides from _____________

Fig. 20-B, p. 546

growthdrop

suffocate

lesserosion

Upgradevehicles

Plastic Waste

• In 1997, ocean researchers discovered a huge swirling mass of plastic waste in the North Pacific Ocean• Due mainly to __________ pieces of plastic• “human throw away mentality”• _________________________________

• Discovered a similar one in 2010 in the Atlantic Ocean…called the ______________________________

• Leading to increased plastic _________________ by marine organisms and birds• Midway a Message from the Gyre

small

Great Pacific Garbage Patch

Great Atlantic Garbage Patch

ingestion

Ocean Pollution from Oil (1)

• Both crude and refined petroleum reach the ocean from a number of sources • Crude petroleum – oil as it comes out of the ________• Refined petroleum – processed petroleum __________

like fuel oil, diesel, gasoline

• Tanker accidents get the most press , but studies show that the largest source of ocean pollution from oil is urban and industrial runoff from __________

ground

products

land

Ocean Pollution from Oil (2)

• Damaging effects of oil…• Volatile organic hydrocarbons in oil _______ many

aquatic organisms immediately upon contact

• Other chemicals in oil form tarlike _________ that float on the ocean surface and coat the _____________ of seabirds and ___________ of marine mammals• Destroys their natural heat _________________ or

__________________

• Heavy oil components ___________ to the ocean floor or wash into estuaries and smother ______________-dwelling organisms

kill

globsfeathers

furinsulation

buoyancy

sinkbottom

Ocean Pollution from Oil (3)

• Damaging effects of oil…• Serious local economic impact to _______________ and

_________________ industry

• Oil Clean Up?• Can be partially cleaned or contained by mechanical

means – floating ___________, skimmer boats, and absorbent devices

• Oil eating bacteria?• Dispersant chemicals?

tourismfishing

booms

Ocean Pollution from Oil (4)

• Scientists estimate that current clean up methods can recover no more than ______ of the oil from a major spill.

• _________________ oil pollution is the most effective and least costly approach

15%

Preventing

BP Deepwater Horizon Blowout in the Gulf of Mexico, April 20, 2010

Fig. 20-18, p. 547

BP Deepwater Horizon Blowout in the Gulf of Mexico, April 20, 2010

• Blow out caused by oil and natural gas escaping from a well that lead to an explosion

• The blow out preventer in this situation __________ and there was not an effective Plan B in place

• Crude oil flowed out of the well until it was effectively “capped” nearly 3 months later

failed

Case Study: The Exxon Valdez Oil Spill

• 1989: The Exxon Valdez oil tanker went off course, collided with a reef, and released ____________ liters of crude oil into Alaska’sPrince William Sound

• 5200 km of coastline• Killed 250,000 seabirds• $15 billion in damages to economy• Exxon paid $3.8 billion in damages and clean-up costs• Led to improvements in oil tanker __________ and

clean-up ________________

41 million

safetymethods

Fig. 20-17, p. 547

Coastal Water Pollution

Prevention CleanupReduce input of toxic pollutants

Improve oil-spill cleanup capabilities

Separate sewage and storm water lines

Use nanoparticles on sewage and oil spills to dissolve the oil or sewage (still under development)

Ban dumping of wastes and sewage by ships in coastal waters

Ban dumping of hazardous material Require secondary

treatment of coastal sewageStrictly regulate coastal

development, oil drilling, and oil shipping Use wetlands, solar-

aquatic, or other methods to treat sewage

Require double hulls for oil tankers

Solutions

Review Questions

• What is another term for a harmful algal bloom (HAB)?

• Why does an oxygen depleted zone form every spring and summer near the mouth of the Mississippi River?

• The largest source of ocean pollution from oil is urban and industrial runoff from ____________.

Red tide (green or brown)

Excess nutrients move there from a large watershed area…More plant growth and decomposition – drop in DO

land