Phosphorus cycle and fertilisers Flashcards
What molecules contain phosphorous?
ATP, phospholipids and nucleic acids.
Where does phosphorus mostly exist?
Phosphate ions in the form of sedimentary rock deposits.
How are phosphates in rocks released?
Weathering and erosion, and the use of fertilisers (rocks reacted with sulphuric acid to produce phosphate fertiliser).
How are phosphates absorbed by plants?
They need to be dissolved in water then absorbed by the root hair cells.
What is guano?
The accumulated excrement of some sea birds and cave dwelling bats that has high levels of phosphate ions
How are phosphate ions released from dead organisms?
Saprobionts decompose them, releasing phosphate ions. Saprobionts release extracellular enzymes to hydrolyse large molecules into small inorganic ions.
Why do farmers need to add fertilisers?
When crops are harvested, plants are removed from the soil so do not decay and replace mineral ions in the soil.
How do fertilisers increase yields?
They enable to plants to make more biological molecules (biomass) and therefore grow more.
What is leaching?
Rainwater dissolves any soluble nutrients and carries them away from the soil.
What is the process called, when excess nitrates or phosphates cause water to become putrid?
Eutrophication
