MBIO 3282 - Section 7.5 - Phosphorous Cycle

Acquiring PO43- (5+)

- The phosphorus cycle mainly involves acquiring PO43- (5+)
- Few microbes catalyze reductions and oxidations of P between PO43- and phosphine (PH3)
- Bacillus caldolyticus: hypophosphite to phosphate
- PO43- needed for nucleic acids, ATP, phospholipids
- Often a limiting nutrient (aquatic environments)
- Microbes very efficient at taking up phosphate
- Some microbes store it as polyphosphate
- Insoluble inorganic minerals (e.g. calcium phosphates) in environment
- In oxic environments PO43- binds to iron
- More available in anoxic environments

Fertilizer

- Fertilizer application can lead to cyanobacterial blooms (e.g. Microcystis, producing microcystin, a liver toxin at sufficient concentration)