Water Quality

Which would a scientist expect to find in a lake that experienced a sudden increase in nitrate levels?

• an increase in temperature
• an increased number of fish
• an increase in dissolved oxygen
• an increased amount of algae and aquatic plants

Which most likely has the highest number of contaminants in the water?

• a water system with moderate turbidity
• a water system with high turbidity
• a water system with low turbidity
• a water system with no turbidity

How do nitrate levels affect the health of a water system?

• As nitrates decrease, there is an increase in plant growth
• nitrates cause bacteria to consume large protein molecules
• nitrates cause aquatic organisms to die due to oxygen depletion
• as nitrates increase, there is an increase in dissolved oxygen

Why is it important to monitor turbidity levels of a water system?

• frogs will destroy fish eggs in murky water
• fish are better able to find food in cloudy water
• water can only be used for recreation when it is clear
• suspended particles diffuse sunlight and absorb too much heat

The following water quality conditions are observed in a lake ecosystem:
high nitrate concentration
ph of 10
low dissolved oxygen
temperature of 60 degrees
Which best describes this ecosystem?

• the ecosystem is suffering the effects of desalination
• the ecosystem is suffering the effects of lake turn over
• the ecosystem is suffering the effects of eutrophication
• the ecosystem is suffering the effects of evapotranspiration

How do phosphate detergents contribute to water pollution?

• by killing plant life
• by stripping the oil from bird feathers
• by over-fertilizing plants in the water
• by removing carbon dioxide from the water

Rainbow trout are found in mountain streams and are sensitive to changes in their habitat.  Which would be the best description for the use rainbow trout in water quality testing?

• biological indicator
• invasive species
• nitrates

If a large amount of fertilizer enters a lake, which will most likely happen?

• the fish population in the lake will increase
• the temperature of the lake will increase
• the number of fish dying in the lake will increase
• the available food supply for fish in the lake in increase

A high concentration of phosphates and nitrates is found in samples of a pond.  Which is most likely the source?

• lake turnover
• eutrophication
• runoff form agricultural fields

A scientist collected water quality data in a protected estuary over time.  He/she measured a nitrate level of 6ppm, and a dissolved oxygen level of 2 mg/l.  Which would the scientist mostly likely conclude about this site?

• nitrate and oxygen levels are normal
• nitrate levels are high, oxygen levels are low
• nitrate levels are high, and oxygen levels are healthy