fertilisers

• What cycles are linked to fertilizers?

  Nitrogen cycle and phosphorus cycle
• Why are fertilizers added to soil?

  To replace lost nitrates and phosphates
• What happens to nutrients when plants are harvested?

  They are removed from the nutrient cycle
• What are the two types of fertilizers mentioned?

  Natural and artificial fertilizers
• What is an artificial fertilizer?

  Inorganic chemicals synthesized
• What is a major advantage of natural fertilizers?

  They are much cheaper or free
• What is a disadvantage of natural fertilizers?

  No control over nutrient proportions
• What is a key benefit of artificial fertilizers?

  Control over nutrient proportions
• What is a major downside of artificial fertilizers?

  They are very soluble in water
• What does leaching refer to?

  Water-soluble compounds washing away
• What process does leaching lead to?

  Eutrophication
• What are the steps of eutrophication?

  1. Nutrients leached into water bodies
  2. Algal bloom occurs due to excess nitrates
  3. Algae block sunlight for underwater plants
  4. Underwater plants die from lack of light
  5. Bacteria decompose dead plants, using oxygen
  6. Oxygen depletion leads to fish deaths
• What is an algal bloom?

  A blanket of algae on water surface
• Why do underwater plants die during eutrophication?

  They cannot photosynthesize without light
• What happens to bacteria when dead plants are present?

  They respire and use up oxygen
• What is the consequence of bacteria using up oxygen in water?

  Other life cannot survive
• What is the final result of eutrophication?

  Anoxic or oxygen-lacking water
• What does anoxic water mean for aquatic life?

  Very little life can be sustained