1. Marine Pollution
- Oil
- Nutrients
- Synthetic Organic Compounds
Reading:
4th Ed. Ch 18, Secs 2-4,7-8
5th Ed. Ch 18, Secs 2-4, 7-8
Graphic: Marine sediments being analyzed for oil contamination following a
January 1996 spill of 828,000 gallons of home heating oil into coastal waters of
Rhode Island. Photo courtesy of NOAA Damage Assessment and Restoration Program.
2. What is Pollution?
Substances that cause damage by interfering with an organism's physical or
biochemical processes
Natural pollutants:
- example: volcanic eruptions (e.g., sulphuric acid)
"Anthropogenic" pollutants:
- introduced by human activity
- example: synthetic organic chemicals (e.g., pesticides)
Graphic: North Inlet - Winyah Bay National Estuarine Research Reserve. NOAA
National Estuarine Research Reserve Collection.
3. Common Types of Marine Pollution
Oil*
Nutrients*
Synthetic Organic Chemicals*
Heavy Metals
Solid Waste
Heat
Sediment
Introduced Species
Graphic: Oil-containment boom. Photograph by M. Hollinger, NODC Biologist.
Courtesy of NOAA.
4. Sources and Characterization of Marine Pollution
Quantity: Amount of a particular pollutant present
Toxicity: Amount of a pollutant required to cause damage
Persistence: Length of time a pollutant lasts in an environment
Graphic: Garrison, Fig. 18.1, 4th Ed. pg 466, 5th Ed.. Pg 439.
5. The Fate of Pollutants
Solubility = the ability of a substance to be dissolved
Common types
Characteristics
Example
of solubility
water soluble
dissolves in water
liquid sewage effluent
fat soluble
accumulates in fatty
DDT, PCBs, some
tissues (binds with fat)
heavy metals
insoluble
doesn't dissolve
oil, plastic
The fate of a pollutant depends on its solubility
6. Sources of Oil Pollution
90% of oil enters the ocean via human activities
Graphic: Garrison, Fig. 18.2, 4th Ed. pg 479, 5th Ed. Pg 439.
7. Types of Oil Spills
Crude oil spills:
- large volume
- most common type of spill
- crude does not dissolve easily
Refined oil spills:
- smaller volume
- less common
- more disruptive for longer periods of time
- a growing concern, as more refined oil is transported by sea
Graphic: Oil scum one year after the Exxon Valdez incident. Cmmdr. J.Bortniak,
photographer. Courtesy of NOAA.
8. What Happens to Spilled Oil?
Natural Processes:
- Evaporation
- Bacterial degradation
- Formation of tar balls, which sink
Cleanup Efforts:
- Recovery
- Burning
- Dispersal
Graphic: Garrison, 4th Ed. Fig. 18.5, pg 470, 5th Ed. Fig. 18.6, pg 442.
9. Consequences of Oil Spills
Ecological impact depends on:
- Location of spill
- Distance to shore
- Water temperature
- Currents, weather
- Composition of affected marine communities
- Amount and type of oil
Graphics: Cleaning up following a 300,000 gallon spill off Rhode Island. Photo
courtesy of NOAA Damage Assessment and Restoration Program.
10. Nutrient Pollution
Eutrophication: Excessive growth of aquatic plants caused by high concentrations
of nutrients
How it happens:
- excess nutrients enter an aquatic system
- plant growth booms
- plants die and decompose
- decomposition uses up oxygen in the water
- animals suffocate or are driven out of prime habitat
Graphic: Estuarine pond covered with green algae. Photograph by M.Hollinger (NODC),
courtesy of NOAA.
11. Causes of Nutrient Pollution
Usual cause = excess nitrogen or phosphorous
"Point source" (source can be tracked to isolated locations)
- wastewater outflows
- factory effluent
"Non-point source" (source of pollution is spatially distributed)
- agriculture runoff
- lawn chemicals
- septic tanks
Graphic: (top) Sewage treatment plant, photo courtesy of NOAA Restoration
Center. (bottom) Agricultural pollution due to uncontained manure. Photo
courtesy of EPA Region 10 and Washington State Dairy Assn.
12. Oxygen Depleted ("Dead") Zones
Nutrient pollution harms
- fisheries
- water quality
Gulf of Mexico
- affects ~20,000 square km (1999)
- impacts a $2.8 billion regional fishery
Lake Erie
- bottom layer of central basin
- occurs in late summer
- a growing concern
Graphic: (top) Extent of the Gulf of Mexico "Dead Zone" courtesy of NOAA
(bottom) The eastern oyster, photo courtesy of US EPA Gulf Ecology Division.
13. Synthetic Organic Chemicals
Sources:
- pesticides (e.g., DDT)
- flame retardants
- industrial solvents
- cleaning fluids
- coolants (e.g., PCBs)
Toxicity:
- Ingestion of small amounts can cause illness or death
- Specific warnings for children and women of childbearing age
- Immunosuppressants
Graphic: Eastern brown pelican, now recovering from near extinction due to
effects of pesticides. NOAA National Estuarine Research Reserve Collection.
14. Biological Amplification
Levels of synthetic organic chemicals in seawater are usually low
Effects are amplified as toxins accumulate in higher amounts in organisms that
are higher in the food web
Graphic: Garrison, Fig. 18.9, 4th Ed. pg 474, 5th Ed. pg 445.
15. Preview of Next Lecture
The Atmosphere: Driving Force for the Ocean
Reading:
4th Ed. Ch 8, Secs 2-9
5th Ed. Ch 8, Secs 2-10