Guano is produced over time from waste from sea birds and contains phosphorus that the birds have eaten.
Guano is responsible for transferring phosphates from the aquatic communities back to the land. The birds eat aquatic organisms that are floating on the surface of the ocean, and once back on land the phosphates can be put back into the food web.
The phosphorus cycle differs from the other major biogeochemical cycles in that it does not include a gas phase; although small amounts of phosphoric acid (H3PO4) may make their way into the atmosphere, contributing—in some cases—to acid rain.
We can't see what Earth's interior is made of, but scientists are able to study it in other ways. Learn how seismic activity helps us understand and describe the inner layers of the earth at Study.com.