Science Focus Topic 5 Notes: Cycles in the Environment
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When organisms breathe, the gases are recycled in the air and used by other organisms. When organisms die, the nutrients they are composed of are recycled back into the environment and used as well.
The Carbon Cycle
Carbon is necessary for all life to exist and is recycled in the environment.
The Water Cycle
All living things require water to survive and this water is also recycled over and over again.
The water cycle (as illustrated) contains 4 processes: evaporation and transpiration ? move water from the Earth to the atmosphere,
condensation and precipitation return the water to Earth.
Pollution in the Environment
Pollution occurs when a substance is added to the environment at such a fast rate that it cannot be broken down, stored or recycled in the air, land, or water in a non-damaging form. Pollutants are substances that cause pollution.
Type of Pollutant
|Acid Rain (high pH level)||Carbon Dioxide|
Reason they are pollutants
|Sulfur and Nitrogen at higher than normal levels in the air, which mix with water to produce acidic precipitation.||Burning of Fossil fuels puts higher than normal levels of CO2 into the atmosphere and the ozone layer (which protects us from radiation is being depleted.|
The Movement of Pollution (accidental contamination of the air, water and ground ? unsafe use)
Bioaccumulation is the process in which a substance builds up in a living organism from the surrounding air or water, or through the consumption of organisms that already have the substance that is being accumulated. It will vary for different species and will depend on sources of contamination, as well as water quality and temperature. It provides increasing levels harmful to species higher up the food chain, because of "biomagnification", where substances like mercury will increase in concentration from microorganisms, to fish, to fish eating predators like otters and loons, and to humans.
The accumulated mercury is shown by the red dots.
Source: Communication Canada