Explain how human activities could affect the phosphorus cycle.

a. phosphorus in rock (reserves) enters slowly into the biosphere by weathering 

b. mining of phosphorus (-bearing) rocks accelerates the natural cycle/faster than natural erosion 

c. (mined) phosphorus is made into fertilizers/animal feeds/other products

OR

artificial fertilizers contain phosphate 

d. (phosphorous products) transported to agricultural areas (all over the world) 

e. with use of fertilizers phosphorus makes its way into the soil 

f. run-off/drainage from farms causes phosphorus to move into aquatic ecosystems 

g. use of detergents adds phosphorus to water 

h. release of sewage adds phosphorus to water 

i. excess phosphorus can lead to over growth of algae and plants in water 

j. decomposition of dead plant material (by bacteria) use up all the oxygen in the water/increase BOD

OR

decomposition of dead plant material causes eutrophication 

k. «eutrophication» can kill fish and other plants / is negative for ecosystems 

l. phosphorus removed (from ecosystem) by the harvesting of agricultural crops