How do humans interfere in the phosphorus cycle?
1 Answer
Mostly through the addition of phosphate-based fertilizers and mining phosphate rock.
Explanation:
Phosphate fertilizers are commonly used in agriculture to boost plant productivity. However, excess amounts of phosphorous added to soils often leach into groundwater or get into streams that then drain into lakes.
In lakes, phosphorus stimulates the growth of algae so much so that the lake can become eutrophic - or starved of oxygen. When this happens, most of the life in the lakes dies off.
Phosphorus is naturally weathered out of rocks and slowly gets transported to the oceans. Mining phosphate rock can accelerate this process and also leave scars on the landscape if the mining companies don't do reclamation. Exposed phosphate rock will also weather and erode more quickly, again speeding up delivery of phosphorous to the oceans.
Exposed and eroding phosphate rock and fertilizer run-off, can also cause a bloom of bacteria along the coast lines, leading to "dead zones," where very little, if any, life is found. See 2nd pic. Black dots are dead zones.
