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Population Size and Ecosystems

Eutrophication and the effects of drainage

  • 3 things to know
  • Component 1

Overview

Two sources of the nutrients that cause it, algal bloom and effect on the animals in the water.

What you need to know

Answer each one before you reveal it.

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Key term

What is eutrophication?

Key term

Name two sources of the nutrients that cause eutrophication.

Key term

Why does fertiliser reach the water rather than staying in the soil?

Questions from this subtopic

Each one with the model answer underneath.

  1. 1

    What is eutrophication?

    Model answer

    The enrichment of a body of water with nutrients, chiefly nitrates and phosphates, and the sequence of changes that follows.

  2. 2

    Name two sources of the nutrients that cause it.

    Model answer

    Fertiliser leached from farmland, and sewage or slurry entering watercourses.

  3. 3

    Why does fertiliser reach the water rather than staying in the soil?

    Model answer

    Nitrate is very soluble, so rain leaches it through the soil into groundwater and streams.

  4. 4

    What is an algal bloom?

    Model answer

    The rapid growth of algae at the water surface in response to a sudden supply of nutrients.

  5. 5

    What is the first consequence of an algal bloom for the plants below?

    Model answer

    The bloom blocks the light, so submerged plants cannot photosynthesise and they die.

  6. 6

    What happens after those plants and the algae die?

    Model answer

    Decomposers multiply as they break the dead material down.

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