nutrient cycles Flashcards
role of saprobionts in recycling them elements
decompose dead organic matter like proteins dna organic waste
by secreting enzymes for extra cellular digestion
absorb soluble needed nutrients and release mineral ions like phosphate ions
mycorrhizae role
it is the symbiotic relationship between fungi and plant roots
fungi act as an extension of plants roots increasing root system SA
increasing uptake and absorption of water and inorganic ions
in return fungi receive organic compounds
egs of bio molecules containing nitrogen
AA protiens enzymes ura dna rna atp nadp
role of bacteria in nitrogen fixation
nitrogen gas N2 converted to ammonia NH3
forming ammonium ions NH4 in soil
by nitrogen fixating bacteria
bacteria role in ammonification
nitrogen containing compounds eg protiens urea from dead organisms and waste broken down decomposed
converted to ammonia - forming ammonium ions in soil
by saprobionts which secrete enzymes for extracellular digestion
describe role of bacteria in nitrification
ammonium ions in soil converted to nitriles then nitrates via 2 step oxidation reaction
for uptake by plant root hair cells by active transport
by nitrifying bacteria in aerobic conditions
role of bacteria in dentrification
nitrates in soil converted to nitrogen gas - reduction
by dentrifying bacteria in anaerobic conditions - no oxygen or waterlogged soil
why does ploughing soil increase its fertility
ploughing - aerating
more ammonium ions converted to nitrile and nitrate
more nitrification and more active nitrifying bacteria
less nitrate converted to nitrogen gas and less dentrification
examples of biological molecules containing phosphorous
phospholipids
dna
rna
atp
nadp
rubp
phosphorous cycle
phosphate ions in rocks released by erosion into soil
phosphate ions taken up by producers plants and algae and incorporate into their biomass
rate of absorption increased my mycrohizzae
phosphate ions transferred through food chain as herbivore eats producers
some phosphate ions lost from animals in waste producuts
sapribionts decompose organic compounds like dna in dead matter and organic waste releasing phosphate ions
why are fertilisers used
replace nitrates and phosphates lost when plants harvested and livestock removed
those removed from soil and incorporated into biomass cant be released into soil through decomposition by saprobionts so improve efficiency of energy transfer
so higher productivity and yield
artificial vs natural fertilisers
natural - organic - eg manure compost or sewage - ions are released during decomposition by saprobionts
artificial contain inorganic compounds of nitrogen phosphorous or potassium
adv of natural over artificial fertiliser
less water soluble so less leaching so less eutrophication likely
organic molecules require breaking down by sapriobionts so slower release of nitrate and phosphate
envi issue of using fertilisers
phosphate and nitrates - dissolve in water = leaching of nutrients into lakes river ocean
= eutrophication
rapid growth of algae in ponds and river so lights blocked
so submerged plant dies as cant photosynthesise
so saprobionts decompose dead plant matter using oxygen in aerobic respiration
so less oxygen so fish to respire aerobically - die
