pH

TEMPERATURE
EFFECTS: changes rate of photosynthesis changes rate of respiration changes DO in water cold water holds more DO hot water holds less DO changes sensitivity of organisms to toxic waste, parasites, disease.

TEMPERATURE
• Thermal pollution = adding warm water to cold water.
CAUSES OF THERMAL POLLUTION:
• Industry (nuclear power plants, paper mills)
• Urban Development (storm water runoff, construction, soil erosion)

DISSOLVED OXYGEN (DO)
ORANGE =
Oxygen
MICKEY
MOUSE =
Water
Fish need
Oxygen
Less Oxygen =
Less fish

DISSOLVED OXYGEN (DO)
TO INCREASE DO:
• Much of DO comes from atmosphere
• Some of DO comes from photosynthesis
TO DECREASE DO:
• Add pollution
• Add organic waste

ORGANIC WASTE = LOW DO
• Organic waste = parts of once living things
EXAMPLES OF ORGANIC WASTE:
Sewage
Farm runoff
Discharge from food processing plants

RAW SEWAGE GOES INTO WATER:
1. Decomposers chow down
2. Decomposers take up oxygen
3. Decomposers reproduce, taking up more oxygen
4. No more oxygen for other animals
5. Nothing left but decomposer & sewagefilled water.

HEALTHY POND

UNHEALTHY POND

pH
• pH = measure of concentration of hydrogen ions in a substance
• Tells whether substance is:
ACID
BASE
NEUTRAL

pH
Measured on scale from 0 to 14
0 = highly acidic (HCl)
7 = neutral (pure water)
14 = highly basic (bleach)
Seawater pH ranges from 7.5 – 8.5
Average pH of ocean water = 7.8
pH of natural water = 6.5 – 8.5
Optimal range for life = 6.5 – 8.2

pH
US Northeastern rain pH =
4.3
Rain elsewhere in US pH =
5.0 – 5.6

pH

pH
SOURCES OF LOW pH IN WATER:
• Acid rain is cause of acid in thousands of lakes
• Burning fossil fuels has increased acid rain
EFFECTS OF LOW pH IN WATER:
• Low pH directly kills fish
• pH < 5, most fish eggs die

NITROGEN
• Living organisms need nitrogen to make proteins
• Nitrates (NO
3
) & Nitrites (NO
2
) are compounds made of nitrogen & oxygen
• Some nitrogen in water is good
• The wrong amount is bad

NITROGEN
SOURCES OF NITROGEN IN WATER:
Human & animal waste fertilizer
EFFECTS OF TOO MUCH NITROGEN:
Lowers dissolved oxygen (DO).

Q: How does Nitrogen reduce the amount of DO?
A: Eutrophication
• Nitrogen feeds algae (green stuff)
• Algae grows & grows
• Algae blocks sunlight
• Underwater plants die
• Algae die and decompose
• The decomposition takes up oxygen
• No DO for organisms, so they die

EUTROPHICATION

NITRATES

PHOSPHATES
• Phosphorus is an element like hydrogen or oxygen
• Phosphorus combines with other things to make phosphates
• Essential for living things
• Usually present in very small amounts
• Too much is bad

PHOSPHATES
SOURCES OF PHOSPHATES IN WATER:
Storm sewer runoff
Soil erosion
Fertilizer
Forest fires
Volcanic eruptions

PHOSPHATES

PHOSPHATES
EFFECTS OF PHOSPHATES:
Eutrophication (same as with nitrates)

EUTROPHICATION

PHOSPHATES

TURBIDITY
• Measures clearness of water
• Murky water = greater turbidity
• Caused by solids blocking sunlight
• Measured using a
Secchi disk or turbidity meter

TURBIDITY

SOURCES:
Human dumping
Construction
Soil erosion
Nitrate pollution
Phosphate pollution
TURBIDITY
HUMAN DUMPING:
Clay
Silt
Industrial waste
Raw sewage

TURBIDITY
EFFECTS:
Clogs fish gills
Smothers eggs
Makes water unlivable

BIO-INDICATORS
• Bio-indicators = organisms that help determine health of water.
• Presence or absence tells something about the water.
• Not always an accurate way to measure water quality.
• Accurate in telling environmental stress

HOW HUMANS AFFECT
BIO-INDICATORS:
Over-fishing
Industrial pollution
Poor farming practices
Adding foreign species

BIO-INDICATORS