What happens to the phosphates when plants and animals die?

When plants and animals die, organic molecules also undergoes decomposition and this causes the incorporated phosphates to go back to the soil or bodies of water.

Explanation:

Phosphates are naturally related to "phosphorus." They play a vital role in the life of animals and plants. Phosphorus can be commonly be found on the earth's land and water (although the land has a smaller amount of it). Plants naturally absorb phosphate from where they're growing. Animals take up phosphates by eating plants. The phosphate that plants get from the soil are considered inorganic. They only become organic when it is incorporated into the plants DNA (since this is an organic molecule).

So, this means that if there's a sufficient amount of phosphate, there will be more plants on earth as it is also important in the process of acquiring nutrients.

When animals and plants die, all of the organic molecules such as phosphate also breaks down and thus, it falls back to the soil or bodies of water. Then, they are ready to enter another Phosphorus cycle.

When animals and plants die, phosphates will return to the soils or oceans again during decay. After that, phosphorus will end up in sediments or rock formations again, remaining there for millions of years. Eventually, phosphorus is released again through weathering and the cycle starts over.