Phosphorus Cycle

Question 1

______ is the form of phosphorus taken up by organisms from the abiotic environment

Answer 1

Phosphate (PO4-3) is the form of phosphorus taken up by organisms from the abiotic environment

Question 2

Phosphate comes from the __________

Answer 2

Phosphate comes from the weathering of rock

Question 3

Phosphate is often at very low concentrations in soil and

aquatic environments for three reasons

Answer 3

1. Weathering of rock (apatite) is a slow process
2. Phosphate tends to bind with many compounds and
   become unavailable for biotic uptake
3. In aquatic systems, these bound compounds
   eventually become locked into sediments

Question 4

PO4 is lost from ecosystems when

Answer 4

PO4 is lost from ecosystems when it becomes deeply
buried in soils or aquatic sediments

Just like Nitrogen, an individual phosphate ion may travel back and forth in the ecosystem before being lost altogether.