Ecological Problems

Biological magnification

• is the tendency of pollutants to become concentrated in successive trophic levels

The "best" example

• of biomagnification comes from DDT.

Plane Spraying DDT

• The chemical pesticide DDT was used around the world from the 1940s through the early 1970s to kill crop-eating and disease-carrying insects.

DDT

• pesticide

Biological Magnification

Increase or concentration of a substance, such as the pesticide DDT, in a food chain.

Silent Spring (1962)Silent Spring (1962)

• Describes how DDT entered the food chain and accumulated in the fatty tissues of animals, including human beings, and caused cancer and genetic damage.

Rachel Carson (1907-1964)

• Silent Springbrought a new public awareness that nature was vulnerable to human intervention.

OZONE DEPLETION

• CFC’s are commonly used as:

• Refrigerants

• Styrofoams

• Solvents

• Aerosols

BANNED

• In the early 1960s studies began to show that the chemical caused reproductive problems in animals and that it often disrupted the food chain. The use of DDT was banned in the United States in 1973.

BANNED

• In the early 1960s studies began to show that the chemical caused reproductive problems in animals and that it often disrupted the food chain. The use of DDT was banned in the United States in 1973.

OZONE

• O + O2 -> O3

• Forms naturally in the stratosphere

• Acts as protecting the earth from UV radiation

OZONE DEPLETION

• Ozone protects the earth from harmful UVB rays.

• It has been thinning over Antarctica.

OZONEO3

• UV rays split

Oxygen that add to O2 to make O3

OZONE DEPLETION

• Ozone = 03 CFC = CCl4

Cl breaks off an oxygen from ozone

Ozone Thinning Culprit: CFC’s

• Chlorofluorocarbons) are synthetic gases in which the hydrogen atoms of methane are replaced by atoms of fluorine and chlorine (e.g., CHF2Cl, CFCl3, CF2Cl2).

Why McDonalds changed to paper containers.

Should the School Use Styrofoam Lunch Trays?

What is being done?

• Montreal Protocol in 1987 ultimately aiming to reduce CFC’s by half by the year 2000.

Ozone Depletion Kills Krill (baleen whale food source)

Krill is a zooplankton

• Krill are dramatically affected by UVB rays.

Reports show an 80% drop in the Population of zooplanction off the coast of southern California.

GLOBAL WARMING: Thegreenhouse effect

• is the rise in temperature that the Earth experiences because certain gases in the atmosphere (water vapor, carbon dioxide, nitrous oxide, and methane, for example) trap energy from the sun.

• Greenhouse Effect Animation

Glacier Melting

• State of the Arctic on Vimeo

GLOBAL WARMING: SEA LEVELS RISE

• Reuters AlertNet - VIDEO: Rising seas threaten the Maldives

DEFORESTATION

• Loss of Forests

REPLANT

“Slash and Burn”

Erosion in Madagascar due to Deforestation

Rainforest Natives

Burned landscape from "Slash and Burn" deforestation

Erosion is More Likely with Deforestation

ACID RAIN

• Acid rain occurs when these gases react in the atmosphere with water, oxygen, and other chemicals to form various acidic compounds. Sunlight increases the rate of most of these reactions. The result is a mild solution of sulfuric acid and nitric acid.

• HowStuffWorks Videos "Acid Rain Videos"

Acid Rain Origins

pH of Acid Rain

• The pH of "normal" rain has traditionally been given a value of 5.6.

• However scientists now believe that the pH of rain may vary from 5.6 to a low of 4.5 with the average value of 5.0.

Water Species Water Tolerance

Ozone Hole

• Over Antarctica a depletion of the ozone layer has been increasing

EXTINCTION

• End of a species

Secondary Extinction

• The extinction of the dodo bird has caused the Calviera tree to become unable to reproduce since the dodo ate the fruit and processed the seeds of that tree.

INVASIVE SPECIES

• Non-native (or alien) to the ecosystem

Kudzu from Japan to stop erosion

Garden purple loosestrife is taking over wetlands

ASIAN TIGER MOSQUITO

• It is a carrier of dengue fever and two forms of encephalitis.

This small mosquitoarrived in

Houston in 1985, apparently in a shipment of used tires.Now is found in

at least 25 states

Zebra Mussel

• Native to the Caspian and Black Seas, the zebra mussel hitched a ride in ballast water of a ship sometime in the mid-1980s and spread throughout the Great Lakes region and down the Mississippi.