Listen&Learn: Eutrophication

Learn about a process commonly caused by fertilizers in lakes.

Pre-listening vocabulary

• nutrient: something that plants and animals need for energy and growth
• fertilizer: a substance that humans use to help crops and other plants grow
• algae: plants that grow on the surface of water
• deplete: to reduce the amount of something by using it all up
• suffocate: to die from a lack of air
• aquatic: relating to water

Listening activity

Podcast: Play in new window | Download (Duration: 1:08 — 1.0MB)

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Gapfill exercise

Eutrophication is a process where a body of fills up with plant nutrients like nitrogen and phosphorus. This usually happens when rain washes crop fertilizers into a lake. The fertilizers, which use nitrogen to help plants grow, cause excess amounts of algae to grow on the of the water. This is called an algal bloom. When the algae die, bacteria use large amounts of to decompose the plant matter. This process is harmful because it depletes the lake’s oxygen, causing fish at the to suffocate. Eventually, the lack of oxygen can create an aquatic dead zone: a place where little to no aquatic can survive.

Comprehension questions

Discussion/essay questions

1. Fertilizers are very useful for humans. They help us grow enough crops to feed large populations. Do you think that we can prevent eutrophication while continuing to use fertilizers? Why or why not?

Transcript

Eutrophication is a process where a body of water fills up with plant nutrients like nitrogen and phosphorus. This usually happens when rain washes crop fertilizers into a lake. The fertilizers, which use nitrogen to help plants grow, cause excess amounts of algae to grow on the surface of the water. This is called an algal bloom. When the algae die, bacteria use large amounts of oxygen to decompose the plant matter. This process is harmful because it depletes the lake’s oxygen, causing fish at the bottom to suffocate. Eventually, the lack of oxygen can create an aquatic dead zone: a place where little to no aquatic life can survive.