13- Energy & Ecosystems Flashcards
Eutrophication- 4) Increase in bacteria (3)
1) bacteria decompose dead plants
2) As number of bacteria increase, oxygen conc in water decreases
3) Fish & other organisms die as insufficient oxygen
Eutrophication- 3) Plant death (1)
- Plants underneath algae eventually die because there is insufficient light for them to photosynthesise
Eutrophication-2) Algal overgrowth (2)
1) Excess nutrients cause ALGAE to rapidly grow on water surface
2) As algae accumulates, light is prevented from reaching the plants in the water beneath
Eutrophication- 1) leaching & overflow (2)
- Fertilisers sprayed onto fields can LEACH through soil or flow into bodies of water (P, L, R)
- This causes a build up of nutrients in the water
Eutrophication- stages
1) leaching and overflow
2) Algal overgrowth
3) Plant death
4) Increase in bacteria
Natural vs artificial fertilisers (2)
natural= organic & taken from O matter Artificial= inorganic & produced specifically to replace nutrients
Agricultural impacts on soil (3)
-leads to depleated nutrients levels (in soil)
due to:
- when crops are removed for harvest they aren’t DECOMPOSED & nutrients aren’t returned to soil for reuse
- when animals removed for slaughter, decreases nutrient levels as not DECOMPOSED
PC- 2) Breakdown of phosphate ions (3)
1) As phosphate ions are transferred through food chain, they are lost as waste or organism dies
2) Saprobionts decompose waste & dead organisms through EXTRACELLULAR digestion
3) phosphate ions released into soil & can be recycled for reuse in cycle
PC- 1) uptake of phosphate ions (2)
- Phosphate ions are assimilated by plants because of SYMBIOTIC relationship between plant roots and mycorrhizae
- Mycorrhizae increase SA if roots so help increase rate of uptake
Mycorrhizae structure & importance (1+1)
- have hyphae (long strands extending from cell body)
- Hyphae increases the SA of plant root system: helping plants to take up inorganic ions & water at faster rate
Stages of phosphorous cycle
1) uptake of phosphate ions
2) Break down of phosphate ions
Saprobionts & nutrition (4)
1) Saprobionts secrete enzymes onto dead organic matter
2) The enzymes break down large insoluble molecules into smaller soluble ones
3) These absorbed by saprobiont
4) saprobiont STORES molecules or uses in respiration
NC- 4) Denitrification (1)
1) Denitrifying bacteria converts NITRATES in soil back to atmospheric nitrogen (N2)
(occurs anaerobically, & requires anaerobic conditions)
NC- 3) Nitrification
1) Nitrifying bacteria convert, ammonium ions > nitrites
2) Another bacteria then converts, nitrites > nitrates
NC- 2) Ammonification (2)
1) when an organism DIES or excretes FAECES> Saprobionts decompose its BIOMASS by EXTRACELLULAR DIGESTION
2) inorganic ammonium ions released into the soil
NC- 1) nitrogen fixation (3)
1) Atmospheric nitrogen (N2) is converted to ammonia (NH3) by nitrogen-fixing bacteria in soil
2) Bacteria form mutualistic relationship with leguminous plants by inhabiting their root nodules.
3) mutualistic as B provide ammonium ions for p and p provide sugars for B
Stages of nitrogen cycle
- nitrogen fixation
- ammonification
- nitrification
- denitrification
saprobionts=
microorganisms that feed on dead or decaying matter
importance of nutrient recycling
nutrients allowed to be continuously reused
Gross primary production (GPP)=
chemical energy store in plant biomass in given area/volume
Net Primary Production (NPP)=
chemical energy store in plant biomass AFTER respiratory losses to environment
NPP=
NPP= GPP-R
Net production of consumers (equation)
N= I - (F+R)
I= chemical energy INGESTED F= chemical energy lost in FAECES & urine R= RESPIRATORY losses
Rate of productivity units=
kj ha^-1 yr^-1
kj= energy unit
ha= per unit area
per year= more representational as takes in seasonal variation
why is energy transfer between tropic levls is inefficient
sun > prdocuer) (3
- only certain wavelengths of light are absorbed
- light has to strike photosynthetic region
- a lot of light is reflected
why is energy transfer between trophic levels inefficient? (producer> PC> SC) (4)
- respiratory losses
- energy lost as heat
- not all of the plant/animal is eaten
- some food is not digested
Farming practices to increase energy transfer efficiency [crops] (3)
simplify food webs to reduce biomass/ energy loss to non-human food chain
- herbicides- kill weed (less competition)
- fungicides- reduce fungal infections (more energy to create biomass)
- pesticides- reduce loss of biomass from crops
Farming practices to increase energy transfer efficiency [livestock]= (5)
reduce respiratory losses (so more energy for biomass creation)
- restrict movement
- keep warm
- slaughter animal when young (when most of the energy is used for growth)
- selective breeding (produce breeds with higher growth rates)
- treated with antibiotics (to prevent energy loss to pathogens)
measuring biomass
can be measured using, either:
- mass of carbon
- dry mass of tissue/ given area.
measuring biomass- dry mass (4)
- sample dried in oven (low temp to avoid combustion)
- Sample reweighed at intervals
- All water removed when mass constant
- Mass of carbon taken to be 50% of dry mass
