1 Review What causes soul erosion 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 Biosphere 6.2 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 Point source pollution 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 Acid rain 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 Particulates 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 Each year, the U.S. EPA estimates emissions from a variety of sources. Look at the graph on pg 137. 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? Interpret Data How does the graph differ from one that shows absolute values for emissions? Describe that graph/ 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?