P Cycle

Question 1

Bio functions

Answer 1

Component bones, ATP, DNA, RNA, cell membranes and proteins

Likely to be limiting factor on bio processes than other nutrients because most P compounds not in atmosphere

Question 2

Main processes involved in phosphorus cycle

Answer 2

Absorption by roots and use in metabolic processes- most plants synoptic relationship w mycorrhizal fungi - extensive network hyphae in soil ^ SA for phosphate absorption

Decomposition- break down of phosphorylated proteins in DOM release phosphates that often made more soluble by soil microbes do they can be absorbed by plants.

Sedimentation - phosphorus from DOM may become incorp into sediment - no longer available to organisms - in sea can make surface less productive as P availability limiting factor.

Mountain building and weathering - slowly mobilise P make available to living organisms. P in marine sediment not available till continental drift -> new mountain ranges and weathering rocks releases phosphates

Question 3

Human impacts on the phosphorous cycle

Answer 3

Mining phosphate rocks - most mined as calcium phosphate used to produce soluble ammonium phosphate.
Bird droppings accumulation mined for ammonia.

Fertiliser use - mobilises phosphorus compounds into env in more soluble forms. ^ crop production and contribute to eutrophication

Question 4

Sustainable management of phosphorus cycle

Answer 4

• P shortage = limiting factor for farmland - removal biomass and soil erosion. Mining to maintain supplies not sustainable.
• bio wastes used as fertilisers to maintain phosphate nutrient availability.
• crop breeding programmes increasing efficiency of phosphate absorption of crops