Carbon and Nitrogen Cycle

effect of deforestation on carbon cycle

-increases carbon dioxide content of atmosphere

-rate of CO2 removal is slowed down

-combustion of trees when they are cut down

the greenhouse effect

-greenhouse gases allow high energy, short wavelength gases to enter atmosphere where much are absorbed and warm up earth

-earth re-radiates lower energy, longer wavelength infra-red radiation which is absorbed and trapped by greenhouse gases in the atmosphere so atmosphere warms up

list effects of global warming

-melting of polar ice caps = flooding coastal area + loss of habitat

-extreme weather conditions

-frequent and extreme fires

-decreased ocean pH as CO2 dissolves = threatens aquatic organisms

Nitrification

-add nitrites/nitrates to soil by converting ammonium

-first converted to nitrites than nitrates

Denitrification

-loss of nitrate from soil

-NO3- ions into NO2

Nitrogen Fixation

-reducing nitrogen into ammonium ions by azotobacter

-NO2 diffuses into legume root nodule and nitrogenase catalyses reduction using ATP

Ammonification

-putting ammonium into soil

-detritivores consume dead organisms, animal waste etc

-decomposers secrete enzymes that decay remains like proteins into amino acids then deaminases reduce them into ammonium ions

how does ploughing affect nitrogen cycle

-improves soil aeration

-favours aerobic organisms = better formation of NH4+ ions

-favours nitrifying bacteria = better conversion of NH4+ into nitrites/nitrates

-oxygen for roots to produce ATP for mineral uptake

how does drainage affect nitrogen cycle

allows air to enter soil to reduce anaerobic conditions

how does artificial fertilizers affect nitrogen cycle

-haber process converts NO2 into NH4+ used to make fertilizers

-fertilizers already contain ammonium/nitrate ions

how does cultivation of legumes affect nitrogen cycle

-planting legumes enhances nitrogen fixation

-after crop dies its ploughed into soil due to high nitrogen content

what are the effects of excess use of fertilizers on grassland

-reduced species diversity on grassland due to increased growth of grass + nettles which shade out smaller plants

what are the effects of excess use of fertilizers in seas

-eutrophication

-algae blooms = light unable to penetrate

-deeper regions cannot photosynthesise so die

-algae die and decomposers use up all oxygen so other aquatic organisms die