phosphorous cycle

give 6 phosphorous containing compounds:

• DNA

• ATP

• RNA (mRNA, rRNA, tRNA)

• phospholipids

• NADP

• triose phosphate

what is weathering?

the breakdown of rocks by wind, water or biological activity, releasing phosphate into soil and water, making it available for producers

what is deposition?

the process where particles, including phosphates, settle out of water and accumulate in layers

what is erosion?

the erosion of rock/soil particles, often containing phosphate, by wind/water/ice

what is sedimentation?

the buildup of layers of particles, like phosphate-rich sediments, at the bottom of bodies of water

what is run-off?

water flowing over land that carries dissolved phosphates into rivers/lakes/oceans

what is guano?

nutrient-rich bird droppings that add phosphate to soils when they decompose

what is the main store of phosphorous?

mainly found as a phosphate ion, in mineral form in sedimentary rock

describe the phosphorous cycle:

• phosphates in rocks are released into the soil and the sea through weathering, erosion and sedimentation

• in the soil, phosphates are assimilated by the root network of the plants

• saprobionts secrete extracellular digestive enzymes onto the dead and waste matter, hydrolysing cell tissues into smaller molecules

• PO₄^3- ions are released into the soil and assimilated by plants

• PO₄^3- ions absorbed by aquatic producers including algae before being passed along the food chain to zooplankton and fish and into seabirds

label this diagram!

1. absorption

2. sedimentation

3. erosion and fertiliser use

4. deposition

5. erosion

6. excretion

7. excretion and decomposition

8. consumption

what are mycorrhizae? what type of relationship do they form with a plant?

• beneficial fungi growing in association with plant roots

• form a mutualistic relationship with plant

how is mycorrhizae beneficial towards plant growth?

• fungi increase SA for water and mineral absorption

• mycorrhizae acts like a sponge so holds water and minerals around the roots

• ∴ makes plants more drought resistant and able to take up more inorganic ions

• → enables plants to take up more relatively scarce ions e.g. PO₄^3- ions, improving plant growth

what do the mycorrhizae fungi receive in return as part of their mutualistic relationship with a plant?

carbon and sugar