Phosphorus Cycle

Elemental Cycling

The transport and transformation of the biotic and abiotic forms of elements (particularly those essential to life) within and among ecosystems

Phosphorus Element

Component of DNA, RNA, ATP, phospholipids, etc.

Very small global quantity

Phosphate

Phosphorus is generally found in this form

Primary production

Phosphorus is essential to what?

The phosphorus cycle is a slow or fast process?

Slow

Phosphorus is lacking in this cycle component

Atmospheric

The phosphrous cycle is highly impacted by what?

Anthropogenic processes

Weathering

Creates new phosphorus inputs

• Biological and geochemical processes

• Breakdown of minerals to release phosphate

Abiotic limiting factors of weathering

Mineral type, topography, climate, biota

Weathering increases with…

Slope, temperature, precipitation

Is weathering reversible or nonreversible?

Nonreversible

Absorption

Free phosphorus chemically adheres to soil or sediment particles

“Fixation”

Varies with soil type

Absorbtion is a _________ process.

Reversible

Dissolves

Phosphorous is soluble in water

Follows surface and subsurface flows

Assimilation

Dissolved phosphorous can be taken up by plants and algae via soil and water

Passed to consumers and moved thorughout food web

Mineralization

Phosphorous returned to soul via urine and feces

Fungi and microbes via decomposition release phosphate from organic tissue

Importance in terrestrial ecosystems

Primary production limitation

Terrestrial phosphorous is limited by

climate, topography, time, biota

Terrestrial plants uptake phosphorous by

Diffusion in roots

Symbiotic relationship with mycorrhizal fungi

Phosphorous in agriculture can…

Increase crop yeilds and increase soil phosphorus removal

Phosphorous is replenished in agriculture by…

flooding, manure, mineral fertilizers

Negative impacts of agriculture phosphorus addition

Increased erosion and runoff

Can lead to eutrophication

Phosphorus in freshwater systems

Limiting element

Interacts with nitrogen

In sediment can reduce limitation

Increases cyanobacteria

Consumers can be limited

Phosphorus in marine systems

Primary production limitation

• similar to freshwater

• Interacts with N

Human impacts

Phosphate mining

Land use practices

Redistribution