The phosphorous sinks are the ocean and ocean sediments.
The ocean holds $3 \times 10^{15}$ moles of phosphorous.
The annual amount of phosphorous input into the ocean, andas well as the amount of burial of phosphorous as sediment is on the order of $10^{10}$ moles.
The sediment is of three categories:
- Phosphorous associated with calcium carbonate
- Organic phosphorous (associated with organic carbon)
- Apatite
See Phosphorous Accumulation in Marine Sediments and the Oceanic Phosphorous Cycle for a detailed analysis.