Production of AMMONIA (NH3) from organic ammonium containing compounds, e.g. urea, proteins, nucleic acids, vitamins
By SAPROBIOTIC microorganisms, decomposers e.g. fungi + bacteria - feed on dead organisms ormaterial - release ammonia- form ammonium ions in soil (NH4+)
Nitrogen returns to non-living component of ecosystem.
- Ammonium compounds in soil are changed to nitrogen compounds that can be used by plants
- Plants use light energy to produce organic compounds
- Nitrifying bacteria - e.g. Nitrosomas - need O2 + well areated soils with good draining
- Oxidation reaction + releases energy,E.g. ammonium ions ---> nitrite ions (NO2-) / nitrite ions ---> nitrate ions (NO3-)
- N2 gas converted into nitrogen containing compounds - industrially, lightning, microorganisms - able to break down N bond ( )
- Free-living e.g. cyanobacteria (water)
- By mutualistic relationship - SYMBIOTIC bacteria e.g. Rhizobium - found inside root nodules of leguminous plants (e.g. peas, clover, beans)
- Provide the plant with nitrogen compounds (amino acids=proteins) and plant provides carbohydrates to the bacteria.
- Anaerobic process - soils are waterlogged
- Fewer aerobic nitrifying/nitrogen-fixing bacteria
- Increase in denitrifying bacteria - converts soil nitrate into nitrogen gas
- By using nitrates in the soil to carry out respiration and produce N2.
Soils must be kept well-aerated - prevent build up of denitrifying bacteria.
Used in intensive farming to replenish nutrients
In natural --> removed from soil by plants + returned when plant dies + is decomposed
Increases productivity - plants makes proteins + DNA with nutrients --> required for better growth of plants --> increase SA of leaf --> increases rate of photosyntheis --> increases productivity
OVERUSE of Fertilisers
1) Reduced Species Diversity - favour growth of grasses, nettles ..
2) Leaching - nutrients removed from soil - rain water dissolves soluble nutrients e.g. nitrates + carries them deep into soil - plant cant reach e.g. organic manure, animal slurry, human sewage, ploughing old grassland, artificial fertilisers
3) Eutrophication --> process by which nutrients build up in bodies of water!!!
1) Little nitrate in lakes + rivers - limiting factor - keeps in check growth of plants
2) Leaching - nitrate concentration increases
3) Algal growth - algal bloom near surface - water turns green - huge increase of algae
4) Dense layer of algae - block light passing to lower depth so now light is limiting factor
5) Death of plants/algae at lower depths - no photosynthesis
6) Growth of saprobiotic bacteria - increase due to a lot of dead organisms and algae grow exponentially as lack of dead plants - no longer limiting factor
7) Death of fish - saprobiotic bacteria use up O2 - increases demand 4 respiration
8) Lake becomes putrid - Drop in O2 conc - limiting factor - releases N - fish die
The CARBON CYCLE
Involves 4 processes : photosynthesis, respiration, decomposition and combustion.
Carbon dioxide in the atmosphere and dissolved in oceans...
- CO2 is absorbed by plants - photosynthesis - becomes carbon compounds in plant tissues
- Feeding + Digestion --> Carbon passed on to primary consumers - secondary - tertiary
- All living organisms die and carbon in dead organisms are digested by decomposers e.g. bacteria and fungi - Saprobiontic nutrition
- Carbon is returned to air (and water) when living organisms carry out respiration - produces CO2.
- Dead organic matter that ends up where there are no decomposers e.g. deep oceans - turned into fossil fuels by chemical change (heat + pressure)
- The carbon released by combustion.
Respiration + Photosynthesis cause fluctuations in CO2 concentrations
Photosynthesis - removes CO2
Respiration - adds CO2
- respiration constantly carried out
- photosynthesis - only takes place in daylight
- CO2 conc falls during the day - being removed by plants
- CO2 conc rises at night
- most plant life exist in northern hemisphere - most land is
- most plant growth - summer - more photosynthesis - more energy to grow
- CO2 conc falls during summer - more being removed by plants
- CO2 conc increases in autumn/winter - fewer plants photosynthesising
Effects of Global Warming
Effects of Global Warming