Nutrient Cycle Flashcards
What is the basic sequence of all nutrient cycles?
Producer takes up the nutrients
Producer incorporates it into complex molecules
when they are eaten this is passed on to the consumer and then up the food chain
When consumer dies the sapribionts break the molecule down and release nutrients back into the soil
Describe what ideal soil is like
many air spaces, well-drained with higher organic matter and high levels of nitrifying bacteria
What is nitrogen used for
Making amino acids or nucleic acid
Can Nitrogen be obtained form the environment?
No, ions are absorbed via active transport in the roots
Name the four stages of the Nitrogen Cycle
Nitrogen fixation
Ammoniafixation
Denitrification
Nitrification
Describe Nitrogen fixation
Nitrogen gas is converted into nitrogen-containing compounds by aerobic microorganisms or lightning strike
Describe the two types of bacteria involved in nitrogen fixation
Free-Living Bacteria= reduces N2 (g) to Ammonia to manufacture amino acids
Mutualistic Nitrogen-fixing Bacteria = live in nodules on the roots of plants, they get carbohydrates from plant and plant get amino acid
Describe Ammoniafixation
Production of ammonia from organic nitrogen-containing compounds
when Sparibionat breaks down waste and dead matter into NH3 which forms NH4+ in the soil
Describe Nitrification
Aerobic oxidation to release energy
NH4+ -> NO2-
NO2- -> NO3-
Describe Denitrification
Anaerobic bacteria in low O2 concentrations covert soil nitrates into gaseous Nitrogen
What is Phosphorus used for?
ATP and nucleic acid
What is the main difference between the Nitrogen and Phosphorus Cycle?
The Phosphorus Cycle has no gases phase
Describe the Phosphorus cycle roughly
P in rocks is eroded to be dissolved in lakes and then is absorbed by plants and digested by animals then returned in remains and waste.
How does most Phosphorus exist?
as PO4+ in sedimentary rock deposits
What is the role of Mycorrhizae?
a mutualistic behaviour
where the fungi extension of root increase the surface area for absorption of H20 and minerals
Why does Mycorrihzae benefit the plant?
Better resistance to drought and easier uptake of ions
What are the 2 types of fertilisers?
Natural and Artificial
Why are minerals needed and what do they cause?
Needed for growth to make plants taller, greater leaf area, increased rate of photosynthesis and increased crop productivity
What are Natural/organic fertilisers made from?
dead and decaying plants and animal remains/waste
What are Artificial /inorganic fertilisers made from?
mined from rocks w/ K P N
gives a guaranteed composition
What bad effects can fertilisers have?
Reduced Species Diversity
Leaching
Eutrophication
Describe Leaching
What is it?
And what health risks does it have?
a process where nutrients are removed from the soil and rainwater carries the dissolved nutrients beyond the plants
Very high NO3- con. in H20 = less efficient O2 transport in babies and links stomach cancer
Define Eutrophication
the process by which nutrient concentrations increase in bodies of water
Describe the stages of Eutrophication
1) NO3- is no longer a limiting factor as nutrients from fertilisers enter the water
2) Algae bloom occurs at the surface which blocks light
3) No photosynthesis, so plants die.
4) Greater Saprobiotic decomposition occurs as 5)Microorganisms respire aerobically (use up oxygen)
6) Less oxygen for fish to respire limiting factor, therefore they die
7) Increase in anaerobic microorganisms; release hydrogen sulphide/ nitrates/ toxic waste
8) Water becomes putrid
Describe a process carried out by microorganisms which adds ammonium ions to soil.
Protein / amino acids broken down
By saprobionts / saprobiotic (microorganisms).
Suggest two ways in which crop rotation may lead to high crop yields.
1.Grow crops / plants with nitrogen-fixing (bacteria);
- (Different crops use) different minerals / salts / nutrients / ions (from the
soil) ; - (Different crops have) different pests / pathogens / diseases.
