Cycles of Nature: The Carbon Cycle Carbon is the building blocks of life (Organic!) CO 2 = Carbon Dioxide Living things take in Oxygen and give off CO 2 through Aerobic or Cell Respiration. Plants take in CO 2 through photosynthesis and produce Oxygen. Organisms contain the most carbon in the Carbon cycle. As organisms die and enter the soil, they eventually become fuel over millions of years (“fossil fuels.”) Natural Processes of Volcanoes give off CO 2

How Humans affect the Carbon Cycle Greenhouse Gases –Excess CO 2 in the atmosphere acts as a trap for heat and water vapor. Global Warming –Warming of the Earth causes ice caps to melt, causing the ocean to change temperature and salinity, raising sea levels, changing climate & weather. Deforestation and Habitat Destruction –Without Trees to undergo photosynthesis to convert CO 2 to Oxygen, Carbon levels will continue to rise. -Removal of trees also harms biodiversity (the amount of different organisms) and habitats for organisms.

Cycles of Nature: The Water Cycle Evaporation – Water taken into the atmosphere Transpiration – Plants losing water through leaves Precipitation – Water that falls from the atmosphere (rain, snow, hail, etc) Runoff – Water that enters the ocean Groundwater – Water that is absorbed into the ground Water vapor is also given off by volcanic eruptions. The Water Cycle helps cool the Earth preventing large changes in Global Temperatures.

How Humans affect the Water Cycle Human Use of Water: –Agriculture –Dams and Deforestation –Urbanization (Living in Cities) –Overuse of Aquifers Saltwater Intrusion Subsidence Clean Water supply –1 billion people (16%) do not have any access to clean water. –Can cause outbreaks of disease (cholera, hepatitis) Acid Rain – Hurts plants, animals and buildings

Cycles of Nature: The Nitrogen Cycle 78% of the air is Nitrogen Plants use nitrogen in their cellular processes Nitrogen is present in our DNA and RNA and in amino acids (proteins). The food chain largely moves Nitrogen around. Bacteria and Lightning takes Nitrogen gas and puts into a useable form (called Nitrogen Fixation) Bacteria have a mutualisitic relationship with plants and live on their roots.

How Humans affect the Nitrogen Cycle Humans contribute extra Nitrogen in the cycle due to fertilizers and animal waste (hog lagoons) that runoff into in the lakes and rivers. Extra Nitrogen in the groundwater can interfere with blood/oxygen levels and cause blue-baby syndrome. Excess Nitrogen can cause Eutrophication which causes aquatic life to die due to the low levels of oxygen. (fish kills) High levels of ammonia is also toxic to animals.