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  • Eutrophication is the process

  • that can happen in a water body,

  • like a river or a lake,

  • when too many nutrients are added to the system.

  • Eutrophication starts with fertilizers, which are rich in

  • nutrients like nitrate and phosphate,

  • are washed into the river or lake system.

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

  • The nutrients are food for algae.

  • The algae grow and reproduce quickly,

  • forming a thick green bloom in the water.

  • This algal bloom will absorb sunlight shining on the water

  • so the sunlight can't reach the bottom.

  • Plants who need this light to photosynthesis will die.

  • The algae will also start to die when

  • they eat up all of the nutrients

  • and run out of food.

  • Next,

  • bacteria start to breakdown the dead plants and algae.

  • That releases more nutrients

  • back into the water

  • continuing the Algal Bloom Cycle.

  • The bacteria, with a continuing supply of food,

  • reproduce into much larger numbers

  • consuming oxygen as they grow and respire.

  • There is not much oxygen in the water to begin with

  • so when the bacteria consume it quickly

  • it might run out completely.

  • Water without oxygen is called Anoxic.

  • If the water turns anoxic

  • all non-bacterial life in the water,

  • including fish and other animals, will die.

  • So,

  • eutrophication happens when nutrients are added to water

  • which causes an algal bloom,

  • cutting off sunlight and feeding bacteria.

  • The bacteria use up oxygen in the water

  • which becomes an anoxic,

  • causing everything living in the water to die.

  • Eutrophication is one reason why we need to be carefull

  • with fertilizers when we are growing crops.

Eutrophication is the process

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