HUMAN IMPACT Human Impact involves discussion of human activities that impact our environment.

Many of the environmental issues is caused by human population growth and human activity.

Human impact – hog waste lagoons Hog waste lagoons lead to water pollution. Storage ponds for all of the poisonous waste, containing antibiotics, hormones, bacteria and pesticides. These can leak and flood over, getting into streams and rivers. Anaerobic bacteria are added to these to turn the volatile gases from the manure into carbon dioxide and methane. What does the methane contribute to?

Human impact – ozone depletion The ozone layer is a layer of O 3 gas that protects us from harmful UV radiation. Chlorofluorocarbons (CFCs) are depleting the ozone layer. Found in aerosol cans, coolants, solvents, and plastic foam. Production has stopped but CFCs take a very long time to break down and are still damaging the ozone layer.

Human impact – global warming Global warming/the greenhouse effect/climate change: Greenhouse gasses like CO 2 and methane (CH 4 ) released into the atmosphere does not allow sunlight to escape, causing the earth to become warmer.

Human impact – beach erosion Climate change leads to increased sea levels and severe storms. Beaches erode as a result. Beach erosion destroys property, and when residents try to prevent beach erosion they disrupt ocean ecosystems. North Carolina sea level rise is twice the global average.

Human impact – biological magnification Some chemicals can not be broken down by decomposers and end up in the bodies of organisms that can’t excrete them. Biomagnification: Buildup of chemicals in the tissue of an organism. Bioaccumulation: Chemicals become more concentrated as they move up the food chain. This effects aquatic ecosystems especially due to more links in the food chain. great blue heron sunfish mayfly nymph algae

Human impact – invasive species Invasive species -species that are not native to the ecosystem Often have no natural predators to maintain population control. Kudzu into the USA Zebra mussels in the Great Lakes Black rats in Europe and USA Burmese pythons in the Everglades

Human impact – decrease in biodiversity Biodiversity – the number of species on earth. Decreasing due to a variety of reasons but mainly habitat destruction. This can lead to a species becoming endangered or even extinct. In the US, 85% of extinction involved habitat loss. Loss of forest in Madagascar

Human impact – the value of biodiversity Biodiversity has medicinal value Rosy periwinkle from Madagascar used to treat 2 forms of cancer – survival rate for childhood leukemia went from 10 to 90%. Fungus was used to derive the antibiotic penicillin. Nine-banded armadillo – used to study leprosy. Pacific Yew tree – bark provides taxol cancer drug.

Human impact – the value of biodiversity In addition to having many species, it is also important to maintain diversity within a species! Genetic drift – drastic decrease in the size of a population leading to a decrease in genetic variation within the species. Can be caused by habitat loss. Natural disasters and migration of small groups of a species can cause genetic drift as well. Even if the population recovers the diversity is still lost! Population decreases

Human impact – habitat destruction Habitat destruction is the main cause of the decrease in biodiversity. Deforestation: removal of trees Fragmentation: separation of habitat units Impervious surface: artificial structures covered by impenetrable materials such as asphalt or concrete. NC example: urban development in the Piedmont.

Human impact – deforestation Deforestation is the removal of trees. Large amounts of forests are cut down each year. Habitat destruction leads to a decrease in biodiversity. The main reason for deforestation is agriculture. Deforestation can lead to soil erosion or run off. Run off depletes the soil of nutrients, increases flooding and adds pollutants (like fertilizer) to bodies of water. NC example: urban development in the Piedmont.

Human impact – water pollution Sources of water pollution often begin on land. Oil from cars Sediment from cleared land Fertilizer Chemical dumping Acid rain Raw sewage Overheated water from power plants

Human impact – hog waste lagoons Hog waste lagoons lead to water pollution. Storage ponds for all of the poisonous waste, containing antibiotics, hormones, bacteria and pesticides. These can leak and flood over, getting into streams and rivers. Anaerobic bacteria are added to these to turn the volatile gases from the manure into carbon dioxide and methane. What does the methane contribute to?