BIO220H1 Study Guide - Genetic Variation, Penicillin, Model Organism

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7 May 2012

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Chapter 1: Eutrophication
- Eutrophication is caused by continuous pollution in form of agricultural run off
or sewage outflows, resulting in high N and P (essential for plant growth)
o Nitrogen eutrophication occurs in inshore marine waters
o Phosphorus eutrophication occurs in freshwater
- Stages of eutrophication:
o 1. Algal Bloom- exponential growth of algae due to high nutrients. Build
up prevent sunlight from getting to other organisms beneath.
o 2. Algae (aka phytoplankton) are short lived and when dead, decomposed
by bacteria that use up oxygen and release CO2, detrimental to other
Green algae (Chlorophyta) exist when some oxygen is still
Blue-green algae (Cyanobacteria) lives in CO2 rich waters.
- In The Lab: 3 water treatments are studied (control, medium, high fertilizer)
o 2 species of each cyanobacteria and chlorophyta + s.molesta
o The following is measured over time:
Conductivity- total number of dissolved ions. Used to study the
salinity of water (saltiness). Run off have high measure.
Conductivity of each treatment will raise overtime (with some
Dissolved Oxygen- over fertilization can reduce levels. Results
showed an increase in oxygen overtime
Nitrate- from fertilizer was used to see the effects. Results showed
increase in levels overtime (especially in high)
Phosphate- again from fertilizer showed same results and
pH measuring the acidity showed to be quite steady, with some
decrease in pH due to higher CO2 levels
Turbidity- measured how unclear the water was and as weeks
proceeded, more foggy water.
- Enriching the Sea to Death (Scott W. Nixon)
- Initial invention of toilets and running water lead to pollution of water sources
like the ocean and rivers.
- Wastewater-treatment technologies were put into place in 1880 to stop animals
from dying. What this treatment did was remove visible debris and pathogenic
organisms. BUT, this didn’t remove the excess nitrogen and phosphorus that
was building up.
- Where nutrients are scarce, phytoplankton are sparse and the water is clear
- Fertilizers cause phytoplankton to multiply exponentially, turning water green.
This ultimately increases the supply of organic mater to aquatic ecosystems=
- Initially, this was not thought to be a problem until 1950’s because people only
saw the benefits in agricultural practices. But water circulates less readily than
air so the build up nutrients can have detrimental effects
- Phytoplankton near surface of water get sunlight, plenty of oxygen
o Short life causes them to die and sink to bottom.
- Dead zones
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