What Is Eutrophication  Agriculture  Biology  FuseSchool
Channel: Infozilla
Date: 21/04/2020

What happens when fertilisers get washed into lakes and rivers?  A process called eutrophication.  Learn all about it in this video.


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Eutrophication is the process

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that can happen in a water body,

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like a river or a lake,

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when too many nutrients are added to the system.

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Eutrophication starts with fertilisers, which are rich in

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nutrients like nitrate and phosphate,

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are washed into the river or lake system.

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This leads to an increase in nutrient concentrations in the water.

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The nutrients are food for algae.

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The algae grow and reproduce quickly,

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forming a thick green bloom in the water.

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This algal bloom will absorb sunlight shining on the water

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so the sunlight can't reach the bottom.

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Plants who need this light to photosynthesis will die.

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The algae will also start to die when

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they eat up all of the nutrients

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and run out of food.

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Next,

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bacteria start to breakdown the dead plants and algae.

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That releases more nutrients

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back into the water

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continuing the Algal Bloom Cycle.

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The bacteria, with a continuing supply of food,

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reproduce into much larger numbers

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consuming oxygen as they grow and respire.

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There is not much oxygen in the water to begin with

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so when the bacteria consume it quickly

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it might run out completely.

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Water without oxygen is called Anoxic.

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If the water turns anoxic

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all non-bacterial life in the water,

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including fish and other animals, will die.

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So,

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eutrophication happens when nutrients are added to water

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which causes an algal bloom,

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cutting off sunlight and feeding bacteria.

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The bacteria use up oxygen in the water

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which becomes an anoxic,

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causing everything living in the water to die.

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Eutrophication is one reason why we need to be careful

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with fertilisers when we are growing crops.


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This video is distributed under a Creative Commons License: 
Attribution-NonCommercial-NoDerivs 
CC BY-NC-ND
Caption author (Vietnamese)
chi nguyễn phạm mai
Caption authors (English)
Paneecha tanakulrungsan
Stephanie Avalos - Padilla
License
Creative Commons Attribution license (reuse allowed)