Using Resources WiselyWhy is soil so important?What are the primary sources of water pollution?What are the major forms of air pollution?

Using Resources Wisely• Humans need to eat, so we can’t just stop cultivating land for

farming and food growth, • In order to continue, we must be sure not to grow anything in

soil that has lost its nutrients due to over farming• How do we obtain what we need from the environment

without destroying it?

Soil Resources• Soil isn’t always the first thing that comes to our minds when

we think about natural resources, but it is a very important one

• Healthy soil helps to support agriculture • Good mineral rich topsoil is very important, because it helps

to retain moisture, and allows water to drain• Good topsoil is produced from long term interactions between

the plants and the soil it grows in

Soil Resources• Soil can be renewable if it is managed correctly, or become

lost if it is mismanaged• Loss of fertile soil can be devestating• In the 1930s, years of poorly managed soil and a severe

drought resulted in the “Dust Bowl”• People lost their jobs and homes, in an area once a booming

farming community known as the Great Plains• It essential turned into desert, and may take centuries to recover

completely

Soil Erosion• Soil erosion is the removal of soil by wind or water• The “Dust Bowl” may have occurred as a result of the

conversion of prairie land into cropland which left it vulnerable to erosion

• It can be worse when soil is cleared of trees and roots which help to hold it together and turned into farmland

Desertification• Desertification happens in dry

climates when there is a combination of over farming, overgrazing, seasonal drought, and climate change which ultimately turns an area into a desert

• About 40% of the earth’s land is considered to be at risk for desertification

Deforestation• Trees help to hold the soil in place, and protect it, they help to

absorb carbon dioxide, and help moderate climate• In some places, like the northeastern united states, areas may

recover after deforestation, but it can take centuries to produce mature, old growth forests

• Grazing and farming after deforestation can permanently change soil, and prevent regrowth of trees

Soil Use and Sustainability• We can manage erosion through controlling and managing

agriculture and forestry• Soil is subject to erosion when it is completely bare• Farmers leave stems and roots from the previous year to help

hold the soil in place between crops• They also plant different crops at different seasons, and in

different years, it helps to replenish nutrients, and cuts down on erosion

Soil Use and Sustainability• Planting crops parallel to the hill, instead of on the slop helps

decrease erosion during water runoff

Freshwater Resources• Humans depend of freshwater , and freshwater ecosystems

for drinking, transportation, industry, waste disposal, and energy

• Some very productive farmlands in America rely on water imported through irrigation systems to survive

• Sources of freshwater are not renewable, but freshwater is renewable• Example: The Ogallala aquifer in South Dakota, and Texas. It took

over a million years to collect water, but is not replenished by any rainfall today, within the next 20-40 years it will run dry

• Only 3% of the water on Earth is freshwater, and a lot of it is caught in ice at the poles

Water Pollution• Pollutants are harmful materials that can enter the biosphere• Point source pollution is when pollutants enter water supplies

from a single source like an oil spill• Most of the time pollutants enter through many smaller

sources, like grease and oil which washes off roads in the rain and into water supplies, these are nonpoint sources

Water Pollution• Pollutants can enter either surface or underground water

sources• Primary sources of water pollution are from industrial and

agricultural chemicals, residential sewage, and nonpoint sources

Industrial and Agricultural Chemicals

• PCBs, a chemical which was widely used in industry until the 1970s turned however it has been banned because PCBs enter mud and sand under bodies of water and can be very difficult to remove

Biological Magnification• Occurs if a pollutant is picked

up by an organism and not broken down or eliminated by it’s body it may end up stored in the tissues of the animals body

• The pollutant concentrations increase in animals as they consume each other

Residential Sewage• What happens when we flush a toilet?• It becomes residential sewage, which is not poisonous, but

does contain high levels of nitrogen and phosphorous• Healthy ecosystems may be able to absorb these elements

with no problem• Large amounts of sewage may stimulate blooms of bacteria

and algae that take away a lot of oxygen from the water and creating ‘dead zones’

Atmospheric Resources• Contains oxygen that we need to breath• Contains Ozone, which blocks harmful sun rays• Greenhouse Gases which regulate global temperature• Atmosphere is not “used up” so it is not important to classify it

as either renewable or non renewable• In general the atmosphere is regulated by biogeochemical

cycles, which can be disrupted by pollution

Air Pollution• Air pollution is caused by smog, acid rain, greenhouse gases,

and particulates• When pollution increases, asthma and skin diseases may

increase…why?

Smog• Gray-brown haze in cities• It is caused by pollution, and creates ozone• Ozone is present in the atmosphere very high up, but at

ground level it is dangerous to our health• China’s Olympic Games, athlete’s concerns

Acid Rain• Nitrogen and Sulfer Compounds from burning fossil fuels in

homes and factories combine with water vapor in the air• They may drift in the air for miles before falling as rain, snow,

or fog• Damages plants’ leaves, changes chemistry of the soil, and

surface water

Greenhouse Gases• Created by cars, burning fuels• Farming and raising cattle for food also creates greenhouse

gases• Some greenhouse gases are necessary but can accumulate

and contribute to global warming

Particulates• Microscopic particles of ash and/or dust• These particles may pass through the nose and mouth and

enter the lungs where they may cause respiratory problems

Air Quality and Sustainability• Air doesn’t stay in one place which makes it difficult to

improve the air quality since it doesn’t “belong” to any particular area

• Leaded Gasoline, and it’s ban improved the lead levels found in lakes, streams, and rivers around the country