Biogeochemical Cycling Earth Science Standards 7 a,b,c,d

Energy flows thru the ecosystem Nutrients is vital to life are constantly being recycled. Biogeochemical cycling: the cycling of nutrients thru the ecosystem. They move nutrients (elements) from the nonliving to living then back again. The earth contains a fixed amount of elements: so they have to be recycled.

4 major Cycles Carbon Cycle Nitrogen Cycle Oxygen cycle Phosphorous cycle

Carbon Cycle Carbon (C) is the base of all life. Comes from atmosphere, CO2. Plants use CO2 to complete the Photosynthesis process: 6CO2 + 6 H20 C6H12O6 + 6O2 Carbon is used to make glucose by plants and algae. Glucose energy gets stored as starch in plant. Animal eats plant and the cycle continues

Pathways for Carbon Cycle Cellular Respiration: the breakdown of glucose so plants can use it for energy. The CO2 is present in the atmosphere from humans exhaling.

Marine Organism CO2 is used to combine with calcium to make hard limestone shells. These limestone shells over million of years become sediments settled = carbon reservoirs.

Carbon into Fossil Fuels The bodies of plants and animals buried for million of years, exposed to Earth’s heat and pressure result in fossil fuels. fuel get burned = CO2 back into atmosphere.

Carbon and/or CO2 released Plate tectonics = volcanic eruption (gas) Weathered materials like limestone Food chain waste returned to the soil where the organic molecules can be utilized and turned back to atmosphere as CO2.

Also involves the creation of methane gas. –Methane a hydrocarbon molecule that is produced by anaerobic bacteria ( without air) as a byproduct of their feeding process. Cows digestive tract Mud of rice paddies

Student activity objective Students will create a diagram that illustrates all the sources from which Carbon is created and recycled back into the ecosystem. –Identify all 7 sources of carbon production (7 points) –Use pictures to help explain the diagram (7 points) –Label the sources and title the diagram (8 points) –Use arrows to illustrate how the cycle continues within the ecosystem. (3 points) Total 25 point assignment due tomorrow!

Oxygen Cycle Most abundant element in the Earth’s crust. 45% Second most abundant gas in the atmosphere 21% Can make up 63% of the human body Some oxygen combined with other elements to form earth minerals and rocks. Dissolved in water, where marine organisms utilize O for respiration. Ozone layer high in the stratosphere is made up of oxygen and helps block ultraviolet rays.

Oxygen Part of the photosynthesis and respiration process. –Photosynthesis: O2 is a by-product. –Respiration: O2 used to break down glucose (plant food) to produce energy for plant growth processes.

Nitrogen Important element (N) that is part of the DNA molecule. Also a component of protein molecules. 5% of the human body is composed of nitrogen. The source of nitrogen for the ecosystem is the atmosphere. Earths atmosphere is 78% nitrogen –Diatomic form n2

Nitrogen Cycle Begins when microscopic bacteria located in the soil and in the roots of legumes combines atmospheric nitrogen with other atoms to form nitrogen compounds= nitrification useable form of nitrogen by plants. Plants use the useable form to produce proteins. Plants containing nitrogen become part of the food chain.

Then waste expelled containing nitrogen returning compounds back to the environment and soil. Then decomposed by detritivores decomposing organisms. –Bacteria change back to N2 diatomic nitrogen

Human activity creating Nitrogen Burning fossil fuels, causes atmospheric nitrogen. –Nitrogen combines with oxygen forming nitrogen oxides. Can mix with water H2O and produce nitric acid(acid rain).

Phosphorus (P) A macronutrient for plants. (P) Also part of DNA molecules of living organisms. Individual cells use phosporus-containg molecules, as an energy source. Major source NOT found in the atmosphere, but rather in rocks. Weathered rocks is the main source for the ecosystem.

Phosphorous Cycle Found in rocks Phosphorous gets weathered Phosphorous gets taken up by plants Plants get eaten by animals Animals waste transfers phosphorous back into the earth. Limited in supply= limiting factor

Complete Cornell notes and the unit summary for biogeochemical notes. Must be 8-10 sentences long.