Download Key Ideas Marine Pollution

Key Ideas
l
Pollution can come from both human and natural
sources.
l
There are many different types of pollutants, each
with different characteristics.
l
Pollutants can be biologically magnified in food
chains.
l
Some changes in global weather and climate are
due to pollution.
1
Marine Pollution
How are marine pollutants classified?
• Natural pollutants
• Human generated pollutants
2
1
Characteristics of a Pollutant
Quantity - the amount of a particular pollutant present
Toxicity - the amount of a pollutant required to cause
damage
Persistence - the length of time a pollutant lasts in an
environment
3
Major Types of Pollutants
l
l
l
l
l
Sewage
Trace metals
Oil
Synthetic organic compounds
Gaseous emissions
4
2
Sources of Oil Pollution
5
Oil Pollution
What is the difference between a crude oil
spill and a refined oil spill?
Crude oil spills are usually larger in volume, and occur
more frequently than spills of refined oil.
Refined oil spills can be more disruptive for longer
periods of time. Components added to oil in the refining
process make it more deadly.
6
3
Fate of an Oil Spill
7
8
4
Oil Spills
l
l
l
l
l
l
l
5 - 10 million tons per year
Loss of volatiles - 25% in days
Emulsification - mixing of oil and water
(“chocolate mousse”); eventually settles
Photo-oxidation - harmless products
Microbial oxidation - harmless products
After 3 months, only black tarry lumps (“tar
balls”) - 15%
Nearshore - limited space and time for these
processes
9
Biological and Physical Effects
l
l
l
l
l
Range from bad taste to carcinogenic to
toxic
Low-boiling aromatics - most toxic and
carcinogenic; effect decreases with time
due to volatility
Low-boiling saturated HCs - anesthesia to
toxic
Stored in fatty tissues
Concentrated up the food chain
10
5
11
12
6
Annual Global Oil Spillage
13
Heavy Metals
Small quantities of heavy metals can cause
damage to organisms. Some examples of heavy
metals that can be toxic are:
• Lead
• Mercury
• Copper
• Tributyl tin
14
7
Sources of Heavy Metal
Pollution
• Coal combustion
• Electric utilities
• Steel and iron manufacturing
• Fuel oils
• Fuel additives
• Incineration of urban refuse
15
16
8
Synthetic Organic Chemicals
17
Synthetic Organic Chemicals
Biological amplification of DDT in a food chain.
18
9
Eutrophication
Excess nutrients caused by pollution can speed the
growth of marine autotrophs. This process is called
eutrophication.
Eutrophication stimulates the growth of some species
and upsets the natural balance of an ocean area.
19
Eutrophication
Dead zones caused by eutrophication. Nutrient runoff from
farmlands causes excess growth of autotrophs, which in turn
depletes the oxygen in an area.
20
10
Dead Zone, Gulf of Mexico
21
Size of Gulf of Mexico Dead Zone
22
11
Solid Wastes and Waste Heat
Solid wastes, especially plastics, can cause
damage to marine ecosystems.
Electrical generating plants give off waste heat,
which can damage ecosystems and harm
organisms.
23
Introduced Species
Ballast water of ships allows species to travel to
environments where they have no natural
predators. Introduced species often upset the
ecological balance of an area.
24
12
Habitat Destruction
What marine habitats are most likely to be
damaged by pollution?
• Bays and estuaries
• Coral reefs
25
Global Changes
What global changes have been caused by pollution?
• Ozone layer depletion, caused by CFCs
• Global warming due to increased greenhouse gases
How the greenhouse effect works.
26
13
Summary
Establishing marine sanctuaries is one action that preserves and
protects marine environments. The solution to environmental problems,
27
if one exists, lies in education and action.
14