nutrient cycles

Question 1

what is ammonification

Answer 1

turning nitrogen compounds into ammonia using saprobionts

Question 2

what is nitrification

Answer 2

turning ammonium ions into nitrate ions
oxidation reaction
carried out by nitrifying bacteria

Question 3

what is nitrogen fixation

Answer 3

nitrogen gas in air is converted into nitrogen - containing compounds
natural/lightning

Question 4

what is denitrification

Answer 4

when soil becomes waterlogged
no oxygen
aerobic nitrifying and nitrogen-fixing bacteria convert nitrates in soil into gaseous nitrogen

Question 5

what happens to phosphates in rocks

Answer 5

they get weathered so form phosphates in soil, rivers, lakes and seas

Question 6

what happens to phosphates in soil, rivers, lakes and seas

Answer 6

plants and algae uptake phosphate ions
forming phosphorus in biological molecules in primary producers

Question 7

what happens to phosphorus in biological molecules in primary producers

Answer 7

animals fed on it
forming phosphorus in biological molecules in primary consumers

Question 8

what role do decomposers play in phosphorus cycle

Answer 8

they turn dead plans and aimals into formation of sediment
they also release phosphate ions into soil or water sources

Question 9

how to decomposers give phosphates to rocks, soil or water

Answer 9

rocks: formation of sediment
soil and water sources: saprobions release phosphate ions into them

Question 10

give the processes during nitrification

Answer 10

ammonia –> nitrites
nitrite –> nitrates

Question 11

give the process of eutrophication

Answer 11

nitrates into water source
algal bloom blocks light
submerged plants can’t photosynthesise so die
saprobions aerobically respire and use up oxygen
no oxygen so fish, so they die

Question 12

how can farmers ploughing soil increase crop yield

Answer 12

aeration allows nitrification
decreases nitrification

Question 13

what are mycorrhizae

Answer 13

associations between plant roots and fungi (fungal hyphae).

Question 14

how does mycorrhizae increase uptake of water and inorganic ions

in what conditions specifically

Answer 14

Fungal hyphae form a network around and within roots, greatly increasing surface area.

especially when they are in low concentration in the soil (e.g. phosphates, nitrates).

Question 15

what does mycorrhizae receive from plant in return

Answer 15

the fungus receives organic compounds (e.g. sugars) from the plant – this is a mutualistic relationship (both benefit).