PHOSPHORUS CYCLE

By Alexandra Coppola

Francine Ryan

Reservoirs

• Terrestrial Rocks • Ocean Bottom Sediments

Not found in troposphere because temperate and pressure are not suitable for gas form of P

Found as Phosphates PO43-

Most abundantly found in

PATHWAYS

GEOCHEMICALPHASE

Weathering/soil erosion of rocks with P → Carried from streams and rivers to oceans → Settle out as Sediments→ Uplifting of seafloor by plate tectonics→ P exposed as terrestrial rock

ECOSYSTEM PHASE

Plants take up dissolved P→ Herbivores eat plants (carnivores eat herbivores) → Decomposers break down waste/dead organisms→ Decomposers release phosphorus

into soil→ Plants take up dissolved P

Marine Ecosystem Phase

P taken up by Plankton → Decomposition of organisms release P in water→ P rich shells become part of marine sediments→ excretion form P rich resources→

dropping accumulate on islands (Guano) → guano deposits return sediments to sea

Human Impact

• Phosphates mined from deposits (see next slide)• Altering natural cycle

• P used as fertilizer for crops • Excess P harmful to ecosystem• Death of cyanobacteria • Depletion of O₂ in H₂O

• Animal waste can pollute streams/rivers• Too much P• P ends up in landfills/waterways from human diets

Mining P