phosphorus cycle

how is phosphorus essential to life

component of cell walls (phosphate backbone) DNA, RNA, ATP

can be limiting nutrient

how can p be a limiting nutrient

Addition of p shows increase of growth of individual organisms or biological process rate

inputs and outputs of soil p usually in molecular form of

po4- phosphate

bioavailable po4 (phospate) from soil minerals

solubilization

bioavalible phosphate (po4) attached to soil particles through chemical process-

sorption

type of soils particles p becomes attached to particularly

clay

soil texture determined by

proportion of sand, silt, clay particles

how does soil ph affect p soil availability

most p availability to plants when neutral ph

acidic- p binds to iron aluminum oxides

basic- p binds to calcium phosphates

acidic ph of soils means p bound up by

iron, aluminum oxides

basic ph of soils means p gets bound up to

calcium phosphates

key differences between p and n cycles

p lack of gaseous phase

eve tho p doesn’t have gaseous phase but can be transported

through dust deposition, aerosols from buring fuel sources (like forest fires)

ex amazon not much on global scale but can be imp in local ecosystems

input of soil organic p from

litter, organic matter inputs, fertilizers

input of soil mineral p from

erosion

what do you need to keep in mind when extracting p

not a renewable resource on a human timescale and not substitutable

also geopolitically concentrated

what does it mean for p extraction being geopolitically concentrated

90% of reserves controled by 6 countries

wont run out on global scale but issues of geopolitical access, high quality phosphate rock reserves

resource vs reserve

total amount of phosphate existing vs amount available to be extracted given technology and economics

bottleneck idea

key changes humans have made to p cycle

speed up p cycle- not slow weathering process anymore

eutrophication!

use of mineral p fertilizers

erosion

increased used of manure

p in sewage

eutrophication means

nutrient enrichment

p moving downstream from agriculture fields to freshwater resources