The Phosphorus Cycle details the slow, vital movement of phosphorus through rocks, soil, water, and living things. Unlike the Carbon Cycle or Nitrogen Cycle, it has no significant atmospheric phase, making its availability a crucial limiter for ecosystems. This indispensable element underpins all life, forming the backbone of DNA and ATP, and is a key component of cell membranes and bones.
The cycle begins with the weathering of phosphate-rich rocks, releasing inorganic phosphate ions into soil and water. Plants absorb these phosphates, incorporating them into organic molecules. Animals then obtain phosphorus by consuming plants or other animals. When plants and animals die, decomposers return organic phosphates to the soil and water, where they can be converted back into inorganic forms available for uptake. Over long geological timescales, some phosphorus can settle at the bottom of oceans, forming new rocks.
Human activities, such as mining for fertilizer and deforestation, significantly impact the phosphorus cycle. Runoff from agricultural lands, laden with excess phosphorus, can lead to eutrophication in aquatic systems, causing algal blooms and oxygen depletion.
