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BTEC

BTEC. Freshwater Ecology Assignment. 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. Pollution.

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BTEC

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  1. 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

  8. How to use the BMWP • 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).

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