phosphorus facts
- no gaseous forms in nature
- highly reactive - not found in elemental form
- a small amount is transported attached to dust particles
- overall pH of an environment changed depending on what anion is present
why is the partial dissociation of phosphoric acid important
because it can donate up to 3 protons
inorganic phosphorus
- in over 300 naturally occurring minerals (e.g. apatite)
- lost of mining of sedimentary rocks
- found in bird dropping - Guano
Phosphorus containing minerals
- apatite
- vivionite
- struvite
- manazite
phosphorus as a vitamin
- essential for healthy teeth
- protects and rebuilds enamel
- helps the body absorb and use Ca
- this helps with bone strength
Phosphorus involvement in cellular functioning
- DNA/RNA
- phospholipids
- ATP
- cell signalling and gene regulation
organic phosphorus
- plants cannot take up this form
- phosphate undergoes esterification with carboxylic acids
- COP bond
- phosphotriesters
- phosphonates
what are phosphotriesters
possibly newly evolved marine bacteria capable of degrading anthropogenic pollutants
what are phosphonates
- found in outer membrane of polysaccharides and can replace lipids in the bilayer
- have a CP bond
- abundant in plant tissue and the ocean
liable Phosphorus
- insoluble
- found in soils
- only bioavailable form of P
- orthophosphate
how do organisms release liable P from complexes
- solubilisation
- chemical process that manipulates metabolism
- more important in soil than sea water - mineralization
- enzymatic process that degrades organic P
how do phosphatase drive remineralisation
- in response to love P availability microbes release enzymes called phosphatases
- there is a huge range of them
- have both a promiscuous and specific substrate range
- have different cellular locations
terrestrial phosphorus cycle
- rock weathering
- incorporation and return of P into/from organisms
- exchange between soil and groundwater
- freshwater lake cycling
- transport to sea
rock weathering
transport down rivers as dissolved and particulate PO43-
(much stays in river systems to transport to sea)
incorporation and return of P into/from organisms
- 5% of weathered P is available
- P availability limits growth - controls other biogeochem cycles
- cell division
- atp
- DNA
- gene regulation
exchange between soil and groundwater
- 5% of weathered P available
- inorganic reactions with minerals are important
- pH dependant
freshwater lake cycling
- stratification of lake water in summer reduced p availability near surface - verticel mixing of nutrients is prevented so P is trapped deeper cooler layers where is is less accesibly to plants and algae
- this limits surface water productivity
- sensitive to anthropogenic inputs
- in winter P cycles better in lakes as there is no stratification but because there is less sunlight productivity is limited
transport to sea
- change of pH within estuaries as seawater is approached is important
- dissolved P may precipitate (higher pH more precipitation)
- P may be dissolved from particulates
- difficult to generalise as dependent on many different factors
oceanic P cycle
- upwelling of nutrient rich waters
- biological productivity, sinking of biogenic particles
- regeneration of P by decomposition of organics
- decomposition of particles below thermocline
- slow exchange between surface and deep waters
- P incorporation into deep sediments
how does depth affect temperature and P content
- have reversed patterns with depth
- warm at the top with low P
- cold at bottom with high P
upwelling of nutrient rich waters
- N, P, Fe
- zones of upwelling have high biological activity - e.g. coast of peru
- phytic zone
- cold waters with less stratification have higher P return to surface
incorporation and return of P into/from organisms
- photosynthesis incorporates P into biota in photic zone
- some sinks can be traces using P isotopes
loss and decomposition of particles below thermocline
- most P is recycled into water and returns by either upwelling or exchange
slow exchange of P across deep water/surface water divide (thermocline)
- an extremely slow process
- temperature changes very rapidly
