Phosphorus in rivers can lakes sinks to the bottom and over thousands of years becomes again.

Your question isn't the most clear, but I think your answer is rocks, or more specifically phosphorous rich rocks because the phosphorous will mix with the sediments on the river's/lake's ground forming phosphorous rich rocks.

That means that It'll become a phosphate mineral and later become phosphorous again when the minerals weather.

Hope it helped,

BioTeacher101

what have scientists found to be the most efficient and effective way to insert new sequences into an individual? a-scientists have created genetically altered foods that release dna during digestion. b-scientists use viruses to insert specific gene sequences. c-scientists irradiate genes so that they can be absorbed through the skin.

i got something better   a catchphrase here it is

ahem  

ahem

what the squwock

explanation: