An increasing human population requires an increased food yield
Fertilisers
Provide chemicals such as nitrates which increase crop yield
Nitrates dissolved in soil water are absorbed into plants, nitrates are used to produce amino acids which are synthesised into plant proteins. To obtain this animals consume other animals or plants for protein synthesis
Fertilisers are used to increase nitrate content of the soil
Fertilisers can leach into fresh water by adding extra unwanted nitrates. This increases algae population creating algal blooms
Algal blooms
Fertilisers leach into fresh water by adding extra unwanted nitrates
Increases algae population
Reducing light levels, killing aquatic plants.
These dead plants and algae become food for bacteria which increase greatly in number.
The bacteria uses up large quantities of oxygen, reducing the oxygen availability for other organisms
Pesticides
Are used to kill any unwanted animals or plants which reduce crop yield
Pesticides sprayed onto crops can accumulate into bodies of organisms overtime. As they are passed along the food chain the toxicity increases
What is the term used to describe the build up of poisonous substances in an organisms body?
Bioaccumulation
Genetically modified (GM) crops
Are crops which have had their genetic material altered to enhance their characteristics
GM crops can be used to reduce the use of fertilisers and pesticides
Biological control
Is the deliberate introduction using a pests natural predator to control pest numbers
