Nutrient Cycles Flashcards
Describe the role of saprobionts in the nitrogen cycle (2)
- uses enzymes to decompose proteins
producing amino acids which are converted by ammonifying bacteria to: - producing ammonia
How could an increase in the concentration of dissolved inorganic phosphates lead to a decrease in the number of fish found in the lake? (6)
- increase phosphate causes increase in plant growth / algal bloom
- plants block out light so plants under surface die
- increase in decomposers (which break down plants)
- decomposers use up oxygen and reduce o2 conc. in water
- during aerobic respiration
- plants unable to photosynthesise so less o2 produced
so fish die because less o2 for respiration
Describe the process that occurs after ammonification that allows plants to absorb the n2 compounds in the soil (3)
- ammonium ions are converted to nitrite ions
- by nitrifying bacteria
- nitrite ions are converted to nitrate ions (by other bacteria)
Describe the role of microorgs in the phosphorus cycle (2)
- function as saprobionts
- that break down molecules of dead organisms to release phosphate ions (in to soil/ water)
Phosphorus is released into the soil and into water sources in the form of:
PO₄³⁻ (phosphate ions)
no gaseous phase of phosphorus in atmosphere
phosphate containing compounds:
- DNA
- ADP
- TP
- GP
- RNA
- RuBP
- phospholipids
how do fungi in plant nodules benefit from being associated to the plant?
through nutrient exchange
* obtain carbohydrates prod. by plants thru photosynthesis
* energy source for fungi
* fungi enhance plants nutrient uptake
explain why an increase in biomass can be taken as a measurement of net productivity (2)
- represents dry mass
- GPP - R
- chemical energy store minus respiratory losses
