9/19/16 Science Agenda Warm up- vocab Work session- video clip diagram notes 9/19/16 Science

THE PHOSPHORUS CYCLE

WHAT IS THE PHOSPHORUS CYCLE? circulation of phosphorous among the rocks, soils, water, and plants and animals of the earth Phosphorus is required by all living organisms most phosphorus occurs in phosphate rock as different combinations of salts

cannot be found in air usually liquid at normal temperatures pressures slowest of the matter cycles limiting factors for plant-growth in marine ecosystems, because they are not very water-soluble

The process of the Phosphorous cycle starts out in the earth’s soil. The soil contains phosphate and when something grows out of the soil it will have phosphate as well. When the plants grow they are consumed by herbivore and omnivore animals The animal’s waste or the animal’s body when it dies becomes detritus (non-living organic matter deteriorates into phosphorus)

Another example of the phosphorus cycle is when rocks are created. The phosphate in the soil moves on and transfers its phosphate to the rocks underwater. When the uplifting of the rocks occurs it takes the phosphate along with it. After that the weathering of rocks occur and the rocks begin to break down into the soil and the phosphate in the rocks ends up in the soil again and the cycle repeats.

Phosphates in organic compounds Uplifting of rocks Phosphates in organic compounds Weathering of rock Phosphates in rock Animals Plants Runoff Detritus Phosphates in soil (inorganic) Phosphates in solution Decomposition Detritivores in soil Precipitated (solid) phosphates Rock

 All these examples of phosphates are inorganic (white boxes)  All these examples of phosphates are inorganic (white boxes). However, the Phosphorus Cycle is also organic (yellow boxes). Not all phosphates in the runoff make it to the water; others sink into the soil. These inorganic phosphates are transformed into organic ones by plants, which are in turn eaten by animals.  The dead animals, retain their internal phosphorus stores and detritivores (scavengers which feed on dead plants and animals or their waste) change the organic phosphates back to inorganic ones.

HOW DO HUMANS INTERFERE WITH THE PHOSPHORUS CYCLE? Cutting and burning of tropical rain forests Burning releases nutrients originally stored in plants and rocks are quickly washed away by heavy rains, causing the land to become unproductive

 Agricultural runoff (natural animal wastes or man made fertilizer) provides much of the phosphate found in waterways.

run-off from mines Mining in areas where rock is rich in phosphorus minerals can create dust that is blown by wind into nearby water systems. Too much phosphorus can lead to the production of too many plants in a lake ecosystem Too many plants= too much oxygen use Too much oxygen removed from the water= dead fish