1. Freshwater Ecology Assignment
BTEC
Freshwater Ecology
Assignment

2. Interdependence
All members of an ecosystem are connected in a network of relationships
The success of the whole system depends on the success of its individuals
The success of an individual depends on the success of the system as a whole

3. Pollution Litter? Noise? Greenhouse gases? Acid rain?
Housing development?
Eutrophication?
Sewage?

4. What is pollution?
‘The addition of a substance or energy by human activity to an ecosystem which upsets its natural balance.’

5. Eutrophication Nitrates and phosphates enter freshwater
(from organic or inorganic source)
Species diversity is reduced
Tolerant species number increase
Increase in nutrient content causes rapid plant/algae growth
Oxygen sensitive species die
Plants/algae die
Respiration from bacteria reduces oxygen content of water
Bacteria feed on decaying plant material

6. BOD Biological Oxygen Demand
‘a measure of oxygen used by micro-organisms decomposing organic matter’
Measure dissolved oxygen in sample
Keep in dark at 20°C for 5 days and measure dissolved oxygen again

7. BMWP Invertebrates need oxygen Some need more than others:
Breathing adaptations
Suitability for lower oxygen
Score reflects this
Invertebrate
BMWP
Score
Beetles 5
Biting midge larvae 2
Bivalves 3
Blackfly larvae
Cased caddisfly larvae 10
Caseless caddisfly larvae 7
Cranefly larvae
Damselfly nymph 8
Flatworm
Freshwater hoglouse
Freshwater mite
Freshwater shrimp 6

8. How to use the BMWP List the organisms present in the sample.
No. Found
BMWP
Stonefly 8 10
Mayfly 17 4
Hoglouse 15 3
Total
No. Species
ASPT
5.67
List the organisms present in the sample.
Give each organism a score according to the BMWP scoring system.
Sum the scores to give a total score for the site.
Divide the BMWP score by the number of species to give the ASPT (average score per taxon).