Nitrogen and Phosphorus cycle + eutrophication Flashcards
What is Nitrogen fixation
Where nitrogen fixing bacteria in the root nodules of the plant convert atmospheric nitrogen gas into different compounds. Carried out by leguminous plants
What are saprobiontic organisms
Decomposers
What is ammonification
It is the decomposition or breakdown of urea, proteins and amino acids from waste or dead organisms into ammonia by saprobiontic organisms, forming ammonium ions in the soil
What is nitrification
Conversion of ammonium ions into nitrate ions using nitrifying bacteria in aerobic conditions
Ammonium is oxidised into nitrite ions
Nitrite is oxidised into nitrate ions
What is denitrification
Converting nitrates into nitrogen gas using anaerobic bacteria, nitrogen gas returns to the atmosphere
What are the key processes in the nitrogen cycle
Nitrogen fixing
Ammonification
Nitrification
Denitrification
What is the use for phosphate ions
ADP/ATP
Phospholipid bilayer
Nucleotides/DNA and RNA molecules
Phosphorus cycle process
Weathering releases phosphate ions from rocks into soil and water sources (run off)
Ions absorbed by plants in soil or algae
Consumers feed on producers to take up ions
Ions released via waste or decomposition by saprobionts are released into soil or water
Phosphate ions can be taken up again by plants or algae or they form a sediment back into rock.
What is Eutrophication process
Mineral ions from excess fertiliser leach from farmland to waterways.
This causes an algae bloom at water surface
Aquatic plants die at bottom of water as sunlight is blocked, algae die as competition too great.
Saprobiontic organisms (aerobic) decompose dead matter, using O2
O2 conc drops and so fish cannot respite and die
Anaerobic bacteria can thrive and decompose dead material, releasing nitrates and toxic wastes
What is free living nitrogen fixing bacteria
Bacteria that reduce nitrogen gas to ammonia for amino acids. Release nitrogen rich compound when they die
What is mutualistic nitrogen fixing bacteria
Bacteria on root nodules of plant
They receive carbs and produce amino acids for the plant
How can denitrification be prevented?
Keep the soil well aerated
What are mycorrhizae?
Associations between types of fungi and the roots of plants
How can the mycorrhizal relationships between plants and fungi be described as?
Mutualistic
What is the benefit of a mycorrhizal relationship between plants and fungi?
Mycorrhiza acts as a sponge , holding water and minerals and increasing surface area for the plants roots.
Water and minerals are readily available for a drought
