ECOSYSTEMS : Cycles

1. ECOSYSTEMS:Cycles www.swpc.noaa.gov/

2. Biochemical Cycling • Cycling of nutrients called biogeochemical cycling • Move nutrients from nonliving world to living organisms and back. • Without recycling, life could not exist • Four biogeochemical cycles • Carbon - Nitrogen • Oxygen - Phosphorus http://upload.wikimedia.org/wikipedia/commons/thumb/2/21/CNO_Cycle.svg/300px-CNO_Cycle.svg.png

3. http://www.kidsgeo.com/images/carbon-cycle.gif

4. Carbon Cycling • Photosynthesis – removes carbon dioxide from the atmosphere and turns it into biomass. • Respiration – returns carbon dioxide to the atmosphere when food is burned by cells. • Carbon is also returned to the environment when an organism dies through the action of detrivores.

5. Carbon Cycling • Some organisms die and accumulate. • Forms large layers of limestone rock • Store carbon in rocks for millions years • Known as carbon reservoir • Weathering returns carbon into atmosphere • Volcanic eruptions add carbon dioxide to atmosphere

6. Carbon Cycling • Alternate path—plants and animals are buried • Exposed to heat and pressure beneath Earth’s surface • Causes chemical changes • Produces fossil fuels—oil and coal • Oil—once living plankton • Coal—remains of plants buried in swamps http://www.mii.org/Minerals/Minpics1/CoalAnthracite.jpg

7. Carbon Cycling • Fossil fuels known as hydrocarbons • Composed of hydrogen and carbon • Burning returns to atmosphere as carbon dioxide http://www.ust.hk/~webpepa/pepa/ways_of_protection/air_general.JPG

8. Carbon Cycling • Creation of methane gas (CH4) • Mud of rice paddies in Asia • Anaerobic bacteria release methane gas • Cows produce methane in their digestive systems. http://www.palacesandtigers.com/images/gallery/sri_lanka/Vil%20Uyana%20rice%20paddy.jpg

9. Oxygen Cycling • One of most important interactions • Photosynthesis and respiration reactions • Photosynthesis consumes carbon dioxide and releases oxygen • Used during respiration and carbon dioxide is released • Vital link between plants and animals on Earth www.rps.psu.edu

10. Oxygen Cycling The Earth’s crust is also a reservoir for oxygen storage. http://lasp.colorado.edu/~bagenal/3720/CLASS21/CO2cycle.jpg

11. Nitrogen Cycling - Nitrification • Begins with bacteria in soil and roots • Combine ammonia with other atoms • Nitrogen compounds absorbed by roots of plants • Used to make proteins http://www.thisland.uiuc.edu/50ways/images/5b.jpg

12. Nitrogen Cycling - Nitrogen Fixation • Legumes harbor bacteria that fix nitrogen in small nodules in their roots. • Convert atmospheric nitrogen to plant-available nitrogen • Used to form proteins and other compounds, which makes nitrogen available to other organisms Nodules on Clover roots http://overton.tamu.edu/clover/cool/NodCrimW.jpg

13. Nitrogen Cycling - Denitrification • Bacteria in the soil break down dead organisms, releasing nitrogen gas into the atmosphere. Denitrification filter, part of wastewater treatment plant. http://www.tampagov.net/dept_Wastewater/information_resources/Advanced_Wastewater_Treatment_Plant/Virtual_Tour/images/denit_filter.jpg

15. Phosphorus Cycling • Major source of phosphorus is not the atmosphere • Found in rocks • Phosphate-containing rocks become weathered (break down) • Main source of phosphorus for ecosystems of Earth http://content.answers.com/main/content/wp/en/thumb/b/b9/180px-PhosphateRockUSGOV.jpg

16. Phosphorus Cycling • Animal wastes contain large amounts of phosphorus • Helps to recycle back through food chain • Rare in some ecosystems • Called a limiting factor http://www.gardening.cornell.edu/lawn/almanac/images/fertilizer3.gif

17. Phosphorus Cycling • Human activity raises phosphorus levels • Waste disposal and use of fertilizer • Causes rapid growth in aquatic plants and algae Result is algae bloom Chokes waterway with overgrowth http://www.waterencyclopedia.com/images/wsci_01_img0017.jpg