Transcript Nov 1 - University of San Diego

Water Pollution – Components
I.
D.
Other Chemicals and Minerals
1.
Acids and acidifying compounds
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Many originate in the atmosphere (sulfuric acid, nitric
acid) or from runoff passing through mine tailings
Aquatic organisms generally intolerant of low pH
Effects
1) Irritates gills of fishes and crustaceans and
interferes with gas exchange
2) Irritates slime layer of fishes (reduces resistance to
pathogens)
3) Erodes shells of aquatic mollusks and arthropods
4) Impedes ability of crustaceans to recalcify after
molting
5) Facilitates release of toxins bound to particles in
sediments
Water Pollution – Components
I.
D.
Other Chemicals and Minerals
1.
Acids and acidifying compounds
•
•
•
Many originate in the atmosphere (sulfuric acid, nitric
acid) or from runoff passing through mine tailings
Aquatic organisms generally intolerant of low pH
Effects
1) Irritates gills of fishes and crustaceans and
interferes with gas exchange
2) Irritates slime layer of fishes (reduces resistance to
pathogens)
3) Erodes shells of aquatic mollusks and arthropods
4) Impedes ability of crustaceans to recalcify after
molting
5) Facilitates release of toxins bound to particles in
sediments
Water Pollution – Components
I.
D.
Other Chemicals and Minerals
2.
Nutrients
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Nitrates, nitrites, phosphates
Common sources
1)
Crop and lawn fertilizers
2)
Manure
3)
Sewage
4)
Detergents containing phosphates and nitrates
Excessive nutrient loading  eutrophication
Effects
1)
Plant growth can clog waterways (ecology, navigation)
2)
Plants can interfere with recreation (swimming, boating)
3)
Algal growth can impede submerged plant growth
4)
Nighttime oxygen depletion
5)
Nitrate  methemoglobinemia (blue baby syndrome)
Nutrients can be difficult to control once in a system
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Recycling and regeneration
Eutrophied water bodies can recover if sources are removed
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Ex: Lake Washington
Kiely 1997 Environmental Engineering
Water Pollution – Components
I.
D.
Other Chemicals and Minerals
3.
Metals
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Normal constituents of fresh waters at low
concentrations
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Human activities sometimes lead to elevated levels
May not be toxic at low concentrations or low trophic
levels
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Toxic at higher concentrations
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May bioaccumulate and biomagnify
Effects
1) Health – Ex: Aluminum interferes with salt
regulation in fishes and causes gills to produce
large quantities of mucus
2) Chelators – Bind nutrients, trace elements, and
other necessary chemicals
Water Pollution – Components
I.
E.
Sediments (Siltation)
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Suspended particles, usually from erosion in
watershed
Especially problematic in areas with
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Plowed fields
Construction sites
Logging sites
Strip-mined areas
Effects
1)
2)
3)
4)
5)
6)
7)
Clog respiratory/feeding structures
Abrade skin and shells
Smother eggs and larvae on bottom
Impair photosynthesis by blocking light
Transport bound chemicals
Decrease aesthetic, recreational, commercial value
(beneficial uses)
Fill in crevices and, eventually, water bodies
Water Pollution – Components
I.
F.
Heat (Thermal pollution)
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Sources
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Especially problematic in areas with low flow rates
Heat discharged per kW generated has dropped by 50-70%
since 1950
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Condenser cooling water from electricity generating facilities
(industrialized nations)
Generation capacity has increased substantially
Total heat discharge today 50-100% greater than in 1950
Effects
1)
2)
3)
4)
5)
Reduces solubility of O2
Increases rate of degradation (exacerbates O2 depletion)
Disrupts life cycles of organisms that use temperature
changes as cues
Enhances development of some eggs/larvae/juveniles and
inhibits/kills others
Alters composition of algal community
- Diatoms dominate cool, oligotrophic waters
- Chlorophytes dominate warm, oligotrophic waters
- Cyanobacteria dominate still warmer waters
Biodiversity – Definitions and Assessment
II.
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Major issue – Potential loss as a result of
human activities
Definitions
A.
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Discussion requires clear consensus about what
biodiversity is and how it’s defined
Fundamental unit = species
What is a species??
Species
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1.
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Group of genetically similar organisms that interbreed
naturally and freely to produce viable, fertile offspring,
but do not share this behavior and outcome with
individuals of other species
Problem: Some people consider this definition to be
inadequate. Why??
Biodiversity – Definitions and Assessment
II.
A.
Definitions
1.
Species
a.
b.
c.
Geographic Isolation
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Populations could interbreed if geographic barrier
could be surmounted
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Separate species? Subspecies? Populations?
Natural Hybrids
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Ex – Horse + Donkey  Mule
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Ex – Queen + Blue  Townsend’s Angelfish
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Separate species? If a natural hybrid disappears, is
it really gone so long as parent species remain?
Polymorphism
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Ex - Hamlets
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How different must two species be to constitute
separate species? Humans and chimpanzees are
estimated to be 98% identical at the DNA level.
Biodiversity – Definitions and Assessment
II.
A.
Definitions
1.
Species
a.
b.
c.
Geographic Isolation
•
Populations could interbreed if geographic barrier
could be surmounted
•
Separate species? Subspecies? Populations?
Natural Hybrids
•
Ex – Horse + Donkey  Mule
•
Ex – Queen + Blue  Townsend’s Angelfish
•
Separate species? If a natural hybrid disappears, is
it really gone so long as parent species remain?
Polymorphism
•
Ex - Hamlets
•
How different must two species be to constitute
separate species? Humans and chimpanzees are
estimated to be 98% identical at the DNA level.
Blue
Queen
Townsend’s
Biodiversity – Definitions and Assessment
II.
A.
Definitions
1.
Species
a.
b.
c.
Geographic Isolation
•
Populations could interbreed if geographic barrier
could be surmounted
•
Separate species? Subspecies? Populations?
Natural Hybrids
•
Ex – Horse + Donkey  Mule
•
Ex – Queen + Blue  Townsend’s Angelfish
•
Separate species? If a natural hybrid disappears, is
it really gone so long as parent species remain?
•
Quagga
Polymorphism and Genetic Variability
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Ex - Hamlets
•
How different must two species be to constitute
separate species?
Barred
Black
Golden
Blue
Indigo
Yellowtail
Biodiversity – Definitions and Assessment
II.
A.
Definitions
1.
Species
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How do we identify a species?
How do we quantify the number of species in an area
when there is disagreement about what constitutes a
species?
Recently: Focus on preservation of processes that lead
to speciation
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Suggests emphasis on conservation of intact
habitat vs. single species (HCP vs. ESA)