AP BIOLOGY

Detailed explanation-1: -Unlike nitrogen, the phosphorus cycle does not have a significant atmospheric component. A chemical distribution of phosphorus between aquatic and particulate components occurs via, e.g., adsorption and precipitation processes.

Detailed explanation-2: -Unlike many other biogeochemical cycles, the atmosphere does not play a significant role in the movement of phosphorus, because phosphorus and phosphorus-based compounds are usually solids at the typical ranges of temperature and pressure found on Earth.

Detailed explanation-3: -We estimate that the total atmospheric burden of P is   2.8 ×1010g 90% of which is over the continents.

Detailed explanation-4: -Phosphorus is cycled back into the soil through precipitation. The phosphorus cycle does not include a gaseous phase, resulting in no significant quantities of atmospheric phosphorus. Phosphorus does not enter the cycle from weathering of sediments and parent material.