Oceanography Lecture Notes Outline

ENVIRONMENTAL CONCERNS

I. Marine Pollution

A. Marine Pollution Defined

1. Define ‘pollutant’ : Any substance that causes harmful effects – directly or indirectly – to organisms or the environment.

2. Define ‘marine pollution’: The action or process by which a pollutant is released into the environment, whether naturally, accidently or intentionally.

3. How to distinguish between natural and human-generated pollutants

B. Sources of Marine Pollutants

1. Airborne emissions from land

2. Shipping and accidental spills

3. Ocean dumping

4. Offshore mining, oil, and gas drilling

C. Charateristics of Pollutants

1. Toxicity defined:

2. Toxicity according to concentration and organism

· High concentration versus low concentration toxicity

· Selective toxicity according to type of organism

3. Biodegradable versus nonbiodegradable

· Define ‘biodegradable’

· Define ‘nonbiodegradable’

· Ways pollutants become broken down in the ocean

v Physical processes

v Chemical processes

v Biological processes

4. Persistence of a pollutant in the ocean

· Persistence varies according to each specific pollutant

· Nonbiodegradable pollutants resist breakdown

v Due to synthetic nature of compounds

v Resemble nothing in nature

v May reside in ocean for thousands of years

D. Types of Marine Pollution

1. Oil Pollution

· Both natural and human-induced oil pollution occurs

· Crude oil less toxic than refined oil products

· Sources and Amounts of Oil pollution (in million metric tons)

v Shipping (1.9)

v River runoff (1.6)

v Industrial and Sewage wastes (0.6)

v Input from air (0.6)

v Natural seeps (0.6 – 10% of total)

v Urban runoff (0.3)

v Tanker accidents (0.2)

v Coastal refineries (0.2)

v Offshore oil production (0.1)

· Largest Oil Spills Since 1980 – Ranked (millions of gallons)

v #1 – Discharge into Persian Gulf during Gulf War

v #2 – Well spill into Bay of Campeche, Mexico

v #3 – Tanker Atlantic Empress

2. Heavy Metals

· Toxic effects of heavy metals

v Very toxic in very samll amounts

v Immune supressor

v Interferes with normal cell metabolism

v Brain damage

v Birth defects

v Concentration buildup upwards marine food chain

Ø Called Biological Amplification or Magnification

· Types of heavy metal

v Lead

v Mercury

v Copper

v Cadmium

· Major sources of heavy metals

v Both natural and human-derived

v Industrial discharge

v Runoff from rivers and urban areas

v Air emissions from burning coal

3. Synthetic Organic Chemicals

· Toxic effects

v Very toxic in very small amounts

v All are considered harmful to sealife

v Concentration buildup upwards marine food chain

Ø Called Biological Amplification or Magnification

v Thin shelled eggs in birds

v Birth defects

v Declining fertitilty

v Depressed immune system

v Negative behaviorial changes

· Types of synthetic organic chemicals

v Chlorinated hydrocarbons

Ø Pesticides

ü Example is ‘DDT’

Ø Flame retardants

Ø Industrial solvents

v Polychlorinated biphenyls (PCB’s)

Ø Widely used to cool and insulate electrical devices

Ø Also used to strengthen wood and concrete

Ø Major problem in seals, sea lions, dolphins and whales

v Dioxin

v Luminescent compounds

· Major sources

v Pesticide residue runoff from farms and yards

v Illegal industrial discharge

v Accidental spills into surface and ground waters

4. Eutrophication-inducing compounds

· Overabundance of organic nutrient compounds

v Fertilizers and detergents

v Nitrates and phosphates

· Define ‘eutrophication’

· Occurs mainly at the mouths of almost all the world’s rivers via runoff

· Sources of compounds

v Wastewater treatment plants

v Farmland runoff

v Factory effluent

v Typically enter ocean via stream systems

· Effects of eutrophication

v Explosive growth of marine autotophs

v Drastic reduction in free oxygen in water

v High bacterial activity

v Marine animal suffocation

v Increased opacity of water column

v Release of toxic substances released from algae

· Occurance of harmful algal blooms or HAB’s

v

· Apparent increase in number and intensity of HAB’s

5. Solid wastes

· Trash including plastic is dumped at sea

· Plastic is virtually nonbiodegradable

· Close to 10% of human solid waste is plastic

6. Radioactive Wastes

· Sources

v Nuclear power plants

v Nuclear weapons plants and storage installations

v Industrial reactors

· Negative effects

v Radiation poisoning

v Very long half-life of radionuclides

· Fundamental problem is finding a safe very long-term waste storage solution

7. Sediment

8. Sewage

· Sources that enter the ocean

v Coastal outfall pipes and pumping station overflow

v Storm channels during heavy rainstorms

v Offshore sewage sludge dumping

v Harbor vessels

· Negative effects

v High concentrations of bacteria and viruses in coastal waters

v Promotion of eutrophication

v Reduction of free oxygen in coastal waters

v Burial and suffication of offshore sea bottoms by sewage sludge

9. Waste Heat

· Sources of thermal effluent

v Mainly generated by seaside power generation plants

v Sewage outfalls

· Negative effects

v Shock to organisms

v Organisms are sucked into intake pipes

10. Induced Exotic Species

· Prime examples of very disruptive organisms

v Chinese mitten crab

v Mediterranean Caulerpa seaweed

E. The Costs of Marine Pollution

1. Costs in the United States in 1998 to control terrestrial, atmospheric and marine pollution

· US governement and industry spent $220 billion

· Each private US citizen spent an average of $800

2. USA lost 4% of its gross national product to environmental damages

II. Habitat Destruction

A. Estuaries and Bays

B. Coral Reefs

C. Establishment of Marine Sanctuaries

III. Global Changes

A. Ozone Layer Depletion

1. Nature of the ozone layer and its changes

2. Causes of depletion

3. Harmful effects of ozone layer reduction/loss

4. Ways to limit depletion/loss

B. Global Warming

1. Nature of the global warming phenomena

· Define ‘greenhouse effect’

2. Causes

· Greenhouse gases buildup

· Types of greenhouse gases

· Sources of greenhouse gases

3. Harmful effects

· Sea level rise

· Climate changes

· Ocean current changes

4. Ways to limit depletion

· Reduce human-generated greenhouse emissions

· Increase carbon sinks

IV. What Can Be Done?

A. Think Globally – Act Locally Philosophy and Lifestyle

1. Stay educated on environment-sensitive topics and events

2. Intelligent personal lifestyle choices

3. Voting choices

4. Support pro-environmental causes