II. Humans Alter the Biosphere

A. Land and Water Pollution 1) Agriculture (man-made monocultures) that must be maintained by a high energy input in fertilizers, pesticides and herbicides

a) Fertilizer runoff increases Eutrophication-increase in the nutrients in water Eutrophication 1) Eutrophication results in Algal Blooms (rapid increase of algae populations)Algal Blooms 2) When the algae die, decomposers use up large quantities of oxygen to break them down 3) Aquatic organisms die from lack of oxygen

b) Pesticide run off accumulates in the water supply resulting in Biological Magnification- the build up of toxins as you move up the food chain

A) Existing landfills are running out of space B) Most communities reject plans for new landfills 1) Landfills are breeding grounds for disease organisms 2) Rainwater filters through the waste picking up toxins and depositing them in ground water 2. Waste disposal (each day Americans throw away enough trash to fill up the RCA Dome 3 times

c) Landfills are not just holes in the ground.Landfills

d) Incinerators reduce trash volume but they pollute the air. Further, the ash that remains is high in toxins.

3. Toxic Waste Disposal A) Transport, handling and disposal of toxic waste is expensive and can lead to illegal disposalillegal disposal B) Abandon Salt mines are presently being used, but production is larger than available storage space C) Scientist are developing microorganisms that can break down toxic waste

B. Air Pollution

1. Burning Fossil fuels (oil, coal and gas) pollutes the air by releasing nitrous & sulfur oxides, particulate, hydrocarbons a) Particulates (soot) builds up and covers buildings and neighborhoods and can cause respiratory problems b) Sulfur, and nitrogen oxides combined with atmospheric moisture and cause acid rainacid rain 1) Acid rain destroys forests, lakes and streams by lowering the pH 2) Few living things can tolerate a pH below 5

C. Hydrocarbons can cause the Greenhouse Effect by preventing heat from dissipating back into space 1) As a result, global temperature could rise and melt polar ice caps cause flooding 2) Planetary weather patterns could be disrupted effecting agriculture

2. Fossil Fuels are non-renewable and highly polluting. World oils supplies could be depleted by 2050

3. Smoke stack scrubbers can reduce polluting emissions but they are expensive and produce toxic ash

C. Habitat Destruction Vs. Wildlife Conservation

1. As man clears more area for expanding cities and agriculture, wildlife, both plants and animals, lose their habitat

Loss of Habitat A) loss of feeding and breeding grounds can result in extinction B) Extinction- the elimination of a species from the biosphere forever Extinction C) If a species is endangered it is near extinction and if it is threatened it is near to being endangeredendangered

The Problem 2. Nearly all medicines were derived from a plant,fungus, bacteria or animal speciesplant 3. If we destroy many species, we may lose the genetic material we need to cure cancer or AIDS.

D.Possible Solutions 1. Natural fertilizers (garbage, manure) and crop rotation with legumes can reduce our dependence on chemical fertilizers 2. Biological controls (InCide, predator species, phermone traps and sterile male techniques) can lower or eliminate our need for pesticides 3. Recycling (metals, glass and paper) will reduce the speed we are using up landfill space. Garbage can be composted to provide fertilizer. 4. Alternate Energy Sources (nuclear, hydroelectric, solar, geothermal, wind, waves) can reduce our use of fossil fuel.