1
What accounts for the largest share of water use in the United States?
thermoelectric power (using water to generate electricity and cool equipment)
Industrial waste often contains these, which can harm aquatic organisms.
Toxic chemicals (metals, acidic runoff from mines).
What source contributes the largest percentage of human-caused ocean pollution according to the lesson?
runoff from land
Explain how oil spills harm aquatic ecosystems in two different ways described in the lesson.
Oil exposes organisms to toxic chemicals and can cover the surface, reducing oxygen in the water; animals can become coated and harmed.
Explain why increasing human population affects freshwater availability
Freshwater is only about 3% of Earth's water, most human activities use freshwater (e.g., irrigation, drinking), and as population grows demand increases so supplies (groundwater, lakes, rivers) become impacted and can be depleted.
Why can dams have negative effects on river ecosystems?
They interfere with the migration of fish and increase soil erosion along banks.
Name one common pollutant type that can come from agricultural runoff.
Fertilizers (excess nutrients like nitrates and phosphates).
Describe two ecological effects of excess nutrients (nitrates and phosphates) entering oceans or coastal waters.
They can cause algal blooms; some blooms are harmful—algae may produce toxins that kill organisms or, when algae die, decomposition uses oxygen and low oxygen can kill fish and other marine life.
What name do some people use for the area of concentrated floating trash in the North Pacific Gyre?
The Great Pacific Garbage Patch.
What two factors listed in the lesson can cause the water level in a well to drop?
Drought (less precipitation to replace groundwater) and people using water faster than it can be replaced.
Urban runoff can contain three kinds of pollution listed in the lesson. Name any two.
Pesticides and fertilizers from lawns; oil and gasoline from vehicles; bacteria and viruses from waste.
Name two everyday human activities that use water but are not needed by other organisms.
washing cars
doing laundry
recreation
transportation
Why can algal blooms cause fish kills?
when it dies and ecomposes, it uses up a lot of oxygen which reduces oxygen available to fish
Freshwater sources include these four main types:
groundwater
lakes
rivers
streams
Give two household actions from the lesson that reduce water pollution or water use.
Use non-toxic cleaning products (e.g., baking soda and vinegar instead of harmful chemicals) and use compost instead of artificial fertilizer.
Why do most efforts focus on preventing water pollution rather than cleaning it up, according to the lesson?
Because once pollution enters water it is difficult and can take decades to remove (especially polluted groundwater), so prevention is more effective.
Describe one way that groundwater supports surface features and what can happen when aquifers are depleted.
Groundwater helps support the rocks and soil above it; when aquifers are depleted empty spaces form and the ground can collapse forming sinkholes.
why is plastic harmful to marine animals
they think its food and eat it or get tangled in it
How can runoff from construction and mines harm aquatic life or water quality?
Construction runoff adds excess sediment that clouds water and blocks sunlight; mine runoff can be acidic and contain metals that contaminate drinking supplies and harm growth/reproduction of aquatic organisms.
This underground area of permeable rock or sediment stores and yields groundwater to wells.
aquifer