ECOSYSTEMS & HUMAN INTERFERENCES II

Carbonification

The destruction of vegetation & burning of fossils are main factors in increasing carbon in the atmosphere

Carbon Cycle

Greenhouse Gasses & Global Warming

Greenhouse effect: reradiation of solar heat toward the earth caused by certain gasses

Human activities increased the concentration of these greenhouse gasses:CO2: from burning of fossil fuels & wood

Nitrous oxide (N2O): fertilizers & animal wastes

Methane (CH4): oil and gas wells, rice paddies

Acid Rain

It is caused by increased levels of Nitrogen oxides (NOx) & (SO2)

Negative effects of acid rain:Destroy forestsPollute waterReduce agricultural yieldIncrease erosionHealth hazard to human (O3 from HC and NOx)

Combustion of fossil fuels is the main cause of acid rain

The burning of fossil fuels releases sulfur oxides and nitrogen that react with water in the atmosphere to produce sulfuric and nitric acids.

Field pH5.35.2–5.35.1–5.25.0–5.14.9–5.04.8–4.94.7–4.84.6–4.74.5–4.64.4–4.54.3–4.44.3

Average pH in 2002

Toxins produced by human can accumulate in the fatty tissues of animals.

They become more concentrated in successive trophic levels biological magnification.

Hazard Waste

Nitrogen Cycle

Also, fertilizers and lightening add nitrogen to soil

Eutrophication Runoff containing high phosphate & nitrogen (Fertilizers) Results in (algal bloom). Leads to massive death of aquatic organisms.

Lake Neatahwanta, Fulton, NY

The Post-Standard, June 4, 2004: Lake algae may be Killing Animals

Human activities & ozone O3, or ozone protects us from (UV)

Ozone layer has been gradually “thinning” since 1975 Due to use of chlorofluorocarbons, chemicals used in

refrigeration and aerosol cans

(a) October 1979 (b) October 2000