Ecosystems and Conservation Biology Chapter 36 Part 4

36.4 Human activities can alter ecosystems

Impact on Chemical Cycles Humans literally move nutrients and resources from one place to another

Carbon Cycle Impacts Industrialization has increased atmospheric CO 2 levels –Burning of wood and fossil fuels

Carbon Cycle Impacts Deforestation –Clearing of forests for agriculture, lumber, etc. –Remove plants that convert CO 2 to O 2

Carbon Cycle Impacts CO 2 allows sunlight in, but traps heat –Greenhouse effect –Raises Earth’s average temperature Global warming

Nitrogen Cycle Impacts Humans move large amounts of nitrogen compounds into the water or air –Some sewage treatment –Fertilizer run-off

Nitrogen Cycle Impacts High nitrogen levels feed rapid growths of algae –Eutrophication –When algae die, the bacteria decomposing them use up all the O 2 in the water

Nitrogen Cycle Impacts Smokestacks and auto exhaust release nitrogen and sulfer compounds into air Combines with water –Nitric acid and sulfuric acid –Acid rain

Water Cycle Impacts Deforestation –Plants unable to return water to the atmosphere Using water faster than water cycle can replace

Biological Magnification As organisms take in nutrients, may also take in pollution –As organism’s nutrients pass through food web, accumulate in higher and higher amounts