3.5.4 Nutrient Cycles Flashcards
Name the general stages in the phosphorus cycle
- Weathering
- Runoff
- Assimilation
- Decomposition
- Uplift
Explain what happens during weathering and runoff?
Phosphate compounds from sedimentary rocks leach into surfaces water and soil
What happens during uplift?
Sedimentary layers from oceans are brought up to land over many years
How does mining affect the phosphorus cycle?
Speeds up uplift
Name the 4 main stages of the nitrogen cycle
- Nitrogen Fixation
- Ammonification
3.Nitrification - Denitrification
Why can’t organisms use nitrogen directly from the atmosphere?
N2 is very stable due to strong covalent triple bond.
What happens during atmospheric fixation of nitrogen
- High energy of lightning breaks N2 into N
- N reacts with oxygen to form NO-2
- NO-2 dissolves in water to form NO-3
Outline the role of bacteria in nitrogen fixation
Mutalistic nitrogen-fixation bacteria in nodules of legumes & free-living bacteria in soil. Use the enzyme nitrogen are to reduce gaseous nitrogen into ammonia.
Outline the role of bacteria in ammonification
- Saprobiontd feed on and decompose organic waster contain nitrogen
- NH3 is released
- NH3 dissolves in water in soil to form NH4+
Outline the role of mycorrhizae
Mutualistic relationship between plant and fungus increases surface area root systems = increase uptake of water and mineral ions
Describe the role of saprobionts in the nitrogen cycles
Thes use enzymes to decompose proteins/DNA/RNA
One environmental issue arising from the use of fertilisers is eutrophication. Eutrophication can cause water to become cloudy
You are given samples of water from three different rivers
Describe how you would obtain a quantitative measurement of their cloudiness.
Use colorimeter
Measure the absorbance of light
And use same volume of water search time
