Water Quality

Which best determines the health of a lake used as a source of

freshwater?

• its depth and width

• its temperature and pH

• its location and depth

• its temperature and depth

How is the number of individuals in a biological indicator species

population related to the health of the water system?

• If the number of individuals shows a steady decline, the health of the water system is also declining.

• If the number of individuals shows a steady increase, the pollution in the water system is also increasing.

• As the number of individuals increases, the population becomes a better biological indicator species.

• As the number of individuals decreases, the population becomes a better biological indicator species.

Which property of water quality is most affected by changes in temperature?

• nitrates

• turbidity

• bioindicators

• dissolved oxygen

Which is the best tool to determine if a recent algal bloom has made the water too basic for aquatic organisms?

• a dissolved-oxygen meter

• a thermometer

• turbidity tube

• a pH meter

Which best compares an oxygen-rich freshwater environment and one that is oxygen-poor?

• Oxygen-rich water is murky, while oxygen-poor water is clear.

• Oxygen-poor water has fish and plants, while oxygen-rich water does not.

• Oxygen-poor water contains excess decaying organic matter, while oxygen-rich water does not.

• Oxygen-rich water is found at the mouth of a river, while oxygen-poor water is found in mountain streams.

Which factor most affects the level of dissolved oxygen in a water system?

• amount of rainfall

• variety of bioindicators

• runoff from a lawn treated with fertilizers

• decreased amount of fish due to overfishing

Which contributes most to an increase in turbidity of a local water system?

• people canoeing or kayaking on the water

• people swimming and jumping into the water

• paved roads and driveways that are adjacent to the water

• community parks and baseball fields that are adjacent to the water

Which best explains how temperature influences the biological activity of a lake?

• The rate of chemical reactions stabilizes at higher temperatures.

• The rate of chemical reactions decreases at higher temperatures.

• Cold water may be saturated with oxygen but unable to support aquatic life.

• Warm water may be saturated with oxygen but unable to support aquatic life.

A lake affected by acid rain would most likely have a pH level in which range?

• 1-2

• 3-6

• 7-9

• 10-12

A lake has suddenly become more cloudy, has decreased algae growth, and contains less dissolved oxygen. The lake has most likely received runoff that contains large amounts of which substance?

• sodium

• acid rain

• nitrogen

• sediment