Nutrient Cycles Flashcards
Carbon Cycle
Gaseous carbon is fixed in the process of photosynthesis and returned to the atmosphere in respiration, metabolism, decay and combustion. Carbon may remain locked up in biotic or abiotic systems for long periods of time e.g. in the wood of trees or in fossil fuels such as coal or oil
Photosynthesis
Plants pull carbon dioxide out of the air through photosynthesis, products are glucose and oxygen
Decomposition
Through the breakdown of organic materials carbon is returned to the atmosphere and soil
Respiration
Animals produce carbon dioxide as a product of cellular respiration which is then released back into the atmosphere
Combustion
Fossil fuels are burnt to release energy, carbon dioxide is a by-product of this reaction and is released into the atmosphere through this process
Nitrogen Cycle
Nitrogen cycles between biotic and abiotic environments. Bacteria plays an important role in this transfer
Nitrogen-fixing bacteria
Fix nitrogen gas by converting it into nitrogen compounds in soil
Nitrifying Bacteria
Convert ammonia to nitrite and nitrite into nitrate
Denitrifying Bacteria
Return fixed nitrogen back into the atmosphere by converting nitrates in soil into nitrogen gas
Nitrogen Fixation
Converts atmospheric nitrogen to a soil form of nitrogen that is usable by plants, the majority of nitrogen fixation occurs when bacteria convert atmospheric nitrogen into ammonia
Denitrification
Nitrates in soil are converted back into nitrogen gas which is released into the atmosphere
Assimilation
Inorganic nitrogen compounds such as nitrates or ammonia are absorbed by plants and other organisms and used to form organic nitrogen compounds such as DNA, amino acids and proteins
Nitrification
The breakdown of ammonia into nitrite and nitrite into nitrate by bacteria
Ammonification
Organic nitrogen compounds in decomposing organism tissue and animal excretions are decomposed by various fungi and bacteria and ammonia is released back into the environment
Hydrological (Water) Cycle
Collects, purifies and distributes the earth’s water
Over Oceans
Evaporation exceeds precipitation. This results in a net land movement of water vapour of land
On Land
Precipitation exceeds evaporation. Some precipitation exceeds evaporation, some precipitation gets locked up in snow and ice for varying lengths of time
Condensation
Conversion of gaseous water vapour into liquid water
Infiltration
Movement of water into soil
Infiltration
Movement of water into soil
Percolation
Downward flow of water through soil
Transpiration
Release of water vapour into the air by plants
Evaporation
Conversion of liquid water into gaseous water vapour
