lesson 12: are abiotic factors affecting the trout?

  •  Dioxin is a name for a group of chemicals that are produced as waste products by some factories. For many years, these chemicals were dumped into lakes and rivers or buried in containers in the ground. These buried containers often leaked or broke sending the chemicals into the groundwater, which eventually ended up in the lakes. This dumping occurred before people understood that these chemicals were harmful to living things.

  •  Dioxin was in the Great Lakes and caused changes in the trout populations

  •  Dioxin as an abiotic factor (non-living)

  • It does not take very much dioxin before it begins to affect the living things in the environment

  • The dioxin levels in the lake were very high during the time that the trout levels were lowest

  • The dioxin levels in the lake were no longer dangerous around the time the trout started to increase again

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Reading 12.1

  •      Algae, tiny water plants, found in the Great Lakes can cause “Green Goo”

  •          Algae grows when the ecosystem is out of balance

  •      One essential nutrient for plants to grow is phosphorus

  •       Too much phosphorus in the water causes algae to grow out of control.  Phosphorus is found in detergents so it has been limited or  banned

  •     Phosphorus also enters from other sources. Fertilizers used on farms and lawns, groundwater where the crops and grass grow in contains phosphorus, homes with leaky sewage systems leak phosphorus from soaps into the groundwater. Waste from pets and farm animals contain phosphorus. Also dishwasher detergent.

  • Lake Erie is the best for algae to grow. It is shallower and warmer than the other Great Lakes.

  •     Algae growing out of control is dangerous: People or animals can get sick if they drink the water, some fish die as they are not getting the oxygen from plants.

  •    Another source of the “green goo” problem: mussels- zebra mussel and quagga mussel. They clean the water but this allows more sunlight causing the algae to grow and make the water green.

  • Two ideas about what causes the algae to grow out of control in the Great Lakes. One is abiotic factors (phosphates in the water) and one is biotic factors (zebra mussels)

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