1 Review What causes soul erosion? Why is soil erosion a problem

Apply Concepts What are 3 ways in which the agricultural and forestry industries can improve the sustainability of soil

2 Review How is fresh water both a renewable and a limited resource

Explain why are some pollutants more harmful to organisms at higher trophic levels

Propose a Solution Pick one source of water pollution and describe a way in which we can reduce its effect.

CH 6 HUMANS IN THE BIOSPHERE6.2 Using Resources Wisely

Soil Resources

Topsoil Mineral and nutrient-rich portion of soil Absorbs and retains moisture Rich in organic matter and nutrients Allows water to drain Low in salts.

Soil Resources

Can be a renewable resource if it is managed properly

Can be damaged or lost if it is mismanaged 1930’s “Dust bowl.”

Soil Erosion

Removal of soil by water or wind Occurs fasters without plants Also removes organic materials Humans cause by over use of land and logging.

Desertification

Process of farmland or other productive biome into desert

Change due to overgrazing, over farming, or drought

40 percent of Earth’s land is at risk.

Deforestation

Loss of forests Hold soil in place, protect the quality of fresh

water supplies, absorb carbon dioxide, and help moderate local climate

Forests can regrow after cutting, but it takes centuries for succession to produce mature, old-growth forests Old growth considered non renewable.

Soil Use and Sustainability

Leaving stems and roots of the previous year’s crop in the soil

Crop rotation Contour plowing

Plant crops across and not down slopes Terracing

Shaping the land to create level “steps” Selective harvest of trees.

Freshwater Resources

Can be either renewable or non renewable Only 3 percent of Earth’s water is fresh water and

most of that is locked in ice at the poles.

Water Pollution

Pollutant Harmful material that can enter the biosphere

Point source pollution Enter water supplies from a single source Think an actual pipe

Non point source pollution Enter water supplies from many smaller sources.

Water Pollution

May enter both surface water and underground water

Primary sources are industrial and agricultural chemicals, residential sewage, and nonpoint sources.

Biological Magnification When a pollutant, such

as DDT, mercury, or a PCB, is picked up by an organism and is not broken down or eliminated from its body.

Biological Magnification

Primary producers pick up a pollutant from the environment

Herbivores eat those producers and concentrate and store the compound

Carnivores eat the herbivores and concentrate and store the compound

Concentrations may reach 10 million times their original concentration.

Residential Sewage

Contains lots of nitrogen and phosphorus Can stimulate blooms of bacteria and algae that

rob water of oxygen Oxygen-poor areas called “dead zones” can appear Also contains microorganisms.

Water Quality and Sustainability

Protect wetlands Sewage treatment Pollution control Careful agricultural practices Water conservation.

Atmospheric Resources

Oxygen Ozone Greenhouse gases.

Air Pollution

Smog Chemical reactions in industrial processes and

automobile exhaust Acid rain

Nitrogen and sulfur compounds combine with water to form nitric and sulfuric acid

From burning fossil fuels.

Air Pollution

Greenhouse gases Burning fossil fuels and forests releases stored carbon Agriculture releases methane

Particulates Microscopic particles of ash and dust released by

certain industrial processes and certain kinds of diesel engines.

Air Quality and Sustainability

Emission standards and clean-air regulations.

Each year, the U.S. EPA estimates emissions from a variety of sources. Look at the graph on pg 137.

1. Interpret Data Describe the overall trend in emissions since 1980. Is this what you would expect given the trends in energy consumption and automobile travel- Explain?

2. Interpret Data How does the graph differ from one that shows absolute values for emissions? Describe that graph/

3. Infer What do you think has contributed to the trends you see in this graph? Why would the EPA be particularly interested in this data?