Phosphorus Cycle Geochemical Cycles continued

Objectives: Describe the process of cycling phosphorus throughout environment. Describe the role that fertilizer plays in both the nitrogen and phosphorus cycle.

What is phosphorus? An element [P] that forms molecules that make up the cells of living organisms Helps form bones and teeth in animals

How do organisms get P? Plants: get P from soil and water Animals: get P from eating the plants Phosphorus cycle: movement of phosphorus from the environment to organisms and then back to the environment.

Phosphorus cycle Occurs very slowly Doesn’t occur in atmosphere because P is rarely a gas.

How does P get in soil and water? 1 st way: rocks erode and small amounts of P dissolve in soil and water Plants absorb P in the soil through roots 2 nd way: Excretion, death and decomposition 3 rd way: washes off the land and into oceans – Phosphate salts-don’t dissolve in water-accumulate at bottom

How can too much N or P effect an ecosystem? Fertilizers contain both Nitrogen and Phosphorus to stimulate faster plant growth What happens when there is an excessive amount of fertilizer used?

Overuse of fertilizer… Excess fertilizer can enter terrestrial and aquatic ecosystems through runoff Causes rapid growth of algae-Algal bloom Algal blooms can deplete ecosystems of nutrients like oxygen & kill organisms