What is eutrophication, and how does it happen?

This is a common topic to come up in exams, often worth many marks. Eutrophication is an ecological process which often occurs when humans are irresponsible with waste products that can end up in bodies of water like lakes and rivers, resulting in the death of flora and fauna in the water. It is best described as a list of events: 1. Nutrients like Nitrates or Phosphates present in waste or fertilisers, run into lakes or rivers. 2. These are essential for plant and algae growth, and the increased amount allows more algae to grow, as nutrients are no longer a limiting factor in their growth. 3. This leads to the growth of algal blooms which is a layer of algae on the surface of the water which blocks sunlight from getting into the water. 4. This means that the plants growing underwater have to compete for sunlight, and without it, they die because there cannot generate energy through photosynthesis. 5. Aerobic Bacteria present in the water will then feed on the dead plants and multiply, consuming the oxygen present and converting it into Carbon Dioxide during respiration. 6. This means that there is not enough oxygen in the water for fish to use for aerobic respiration, so they die.