the phosphorus cycle

Question 1

what are the main processes involved in the phosphorous cycle

Answer 1

1) absorption by roots
2) decomposition
3) sedimentation
4) mountain building and weathering

Question 2

outline the process of root absorption

Answer 2

• plants absorb phosphorus for metabolic processes

- they are not effective at absorbing phosphates so often have symbiotic relationships which fungi

Question 3

outline the process of decomposition

Answer 3

• breakdown of phosphorylated proteins in dead organic matter releases phosphates into the soil

Question 4

outline the process of sedimentation

Answer 4

• when phosphorus organism die they become incorporated into sediments such as planktonic organisms which die and sink to the ocean floor, therefore they are no longer available to organisms reducing productivity

Question 5

outline the process of mountain building and weathering

Answer 5

processes which mobilise phosphorus and make it available to living organisms are often slow
- phosphorus in marine sediments may not be available again until continental drifts form new mountain ranges and weathering of rocks releases them

Question 6

what are the human impacts to the phosphorus cycle

Answer 6

1) mining of phosphate rocks

2) fertiliser use

Question 7

outline the mining of phosphate use and how it impacts the cycle

Answer 7

• most is mined as calcium phosphate then treated to produce ammonium phosphate which is more soluble

Question 8

outline the impact of fertiliser use

Answer 8

increases mobility of phosphates into the environment which increases crop productivity and also contributes to eutrophication

Question 9

list some management techniques for the phosphorus cycle

Answer 9

1) biological wastes should be used as fertilisers to maintain phosphate nutrients availability
2) crop breeding programmes are increasing efficiency of phosphate absorption by corps