Lake Chemistry, Stratification and Zones

Which of the following factors affects dissolved oxygen in a lake or stream? (More than one answer is correct)

• Wind

• Plant Life

• Rocks and Water Flow over Rapids

• Animal Decay

How does temperature affect the amount of dissolved oxygen in water?

• Increasing temperature increases dissolved oxygen

• Temperature has not effect on the amount of dissolved oxygen

• Dissolved oxygen in water increases with decreasing temperature

What are the sources of dissolved oxygen depletion in water bodies?

• Organic matter decomposition, eutrophication

• Lack of sunlight

• Decreased temperature

• Increased atmospheric pressure

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NGSS.MS-LS2-4

Why is phosphorus important in water ecosystems?

• Phosphorus has no impact on water ecosystems.

• Phosphorus is important for plant and algae growth and cellular processes in water ecosystems.

• Phosphorus is only important for terrestrial ecosystems, not water ecosystems.

• Phosphorus is harmful to plant and algae growth in water ecosystems.

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How does phosphorus affect the growth of algae in lakes?

• Phosphorus has no effect on the growth of algae in lakes.

• Phosphorus inhibits the growth of algae in lakes.

• Phosphorus only affects the growth of algae in oceans, not lakes.

• Phosphorus acts as a nutrient for algae, promoting their growth in lakes.

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What are the effects of nitrogen in lakes?

• The effects of nitrogen in lakes include decreased nutrient availability and decreased fish populations.

• The effects of nitrogen in lakes include increased biodiversity and improved water quality.

• The effects of nitrogen in lakes include reduced algal growth and increased oxygen levels.

• The effects of nitrogen in lakes include eutrophication, algal blooms, oxygen depletion, and the formation of harmful toxins.

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How does nitrogen contribute to eutrophication?

• Nitrogen has no effect on eutrophication

• Nitrogen reduces the growth of algae and other aquatic plants

• Nitrogen increases the oxygen levels in water bodies

• Nitrogen promotes excessive growth of algae and other aquatic plants, leading to oxygen depletion and harm to other aquatic organisms.

Tags

NGSS.MS-LS2-4

What are the main sources of nitrogen in lakes?

• Runoff from agricultural fields, sewage treatment plants, and atmospheric deposition.

• Industrial waste, volcanic activity, and groundwater seepage.

• Rainwater, evaporation, and groundwater recharge.

• Fish waste, algal blooms, and sediment erosion.

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Label the stratificaitons

c

d

e

b

a

Coldest Stratification

Metalimnion

Hypolimnion

Epilimnion

Thermocline

Tags

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The pH of a ​ (a)   is 7.1 - 14, whereas the pH of an ​ (b)   is 6.9 - 1. A ​ (c)   pH is 7. Most aquatic ecosystems have a pH between ​ (d)  

• base
• acid
• neutral
• 6-8
• 3-5
• 5-7