Environmental Chapter 2

1. Environmental Chapter 2

2. Biogeochemical Cycles • Most things in nature get recycled and are used over again • Three common cycles • Water cycle • Carbon cycle • Nitrogen cycle

3. The Water Cycle • Water moves through the biotic and abiotic factors in the environment • Ways water can move: • Precipitation • water moves from the atmosphere to the land in the form of snow, rain, sleet and hail. • During condensation water cools and condenses, precipitation forms • About 91% falls into oceans. The rest falls on land to replenish the fresh water supply

4. Evaporation • Water moves from the land to the atmosphere • Transpiration is when water moves from living things to the atmosphere. It is a form of evaporation

5. Ground Water – when precipitation seeps into the ground and becomes part of the water table

6. Runoff • Water that flows on top of the ground

8. The Carbon Cycle • All living things have carbon in them • All carbon that is on earth has been here since the earth was formed

9. Ways that carbon moves through the environment • Photosynthesis – carbon gets taken out of the air and used by producers to make food • Respiration- carbon gets put back into the air by animals when they exhale • Decomposition – breakdown of dead materials by bacteria and fungi • Combustion – carbon in fossil fuels is released while burning

11. The Nitrogen Cycle • 78% of the earth’s atmosphere is nitrogen • Organisms cannot use nitrogen directly from atmosphere • Nitrogen fixation- when bacteria in the soil change atmospheric nitrogen gas into usable nitrogen • Lightening can also fix nitrogen • Denitrification-different bacteria change usable nitrogen into atmospheric nitrogen gas