The Cycling of Matter

Why Learn About This? Most minerals essential for life cycle between living things and the atmosphere or the ground Atmosphere—gases surrounding Earth Biosphere—living ‘layer’ of Earth Lithosphere—soil/rock layer of Earth Hydrosphere—water parts of Earth Earth is a “closed” ecosystem The only thing in is sun (energy), the only thing out is some heat(energy) Energy ‘flows through’, but matter ‘cycles within’

Carbon Cycle

Carbon Carbon exists in the nonliving environment as: Carbon dioxide (CO2) Carbonic acid ( HCO3−) Carbonate rocks (limestone and coral = CaCO3) Deposits of Fossil fuels Dead organic matter

Organic Carbon Hydrocarbons: CH4 Carbohydrate: CH2O

Inorganic carbon Carbon Dioxide: CO2 Calcium Carbonate: CaCO3 Mandale Limestone Quarry

Carbon Cycle Short Term All livings things are composed of carbon Green plants and algae convert CO2 in the atmosphere along with water into carbohydrates. These carbohydrates are used as a source of energy for all other organisms CO2 is recycled when autotrophs and heterotrophs release it back into air during celllular respiration.

Carbon Cycle Long Term Carbon enters a long-term cycle when organic material is buried underground and converted to peat, oil, coal or gas. This can take millions of years Carbon is released when fossil fuels are burned Carbon can also enter in a long term cycle in the form of calcium carbonate (found in shells of marine animals) when they fall to the ocean floor and create vast deposits of limestone rock. Carbon is released due to weathering and erosion

Carbon Cycle

Carbon reservoirs Parts of the Earth system where carbon is stored is called carbon reservoirs

Carbon reservoirs The atmosphere. The biosphere (include fresh water systems and non-living organic material, such as soil carbon). The oceans ( including dissolved inorganic carbon and living and non-living marine biota). The lithosphere (sediments, Earth core including fossil fuels).

Carbon Cycle The movement of carbon, in its many forms, between the biosphere, atmosphere, oceans, and geosphere is described by the carbon cycle.

Carbon is released into the atmosphere in several ways Respiration by plants and animals. Decay of animal and plant matter. Combustion of organic material Production of cement. The ocean releases CO2 into the atmosphere. Volcanic eruptions and metamorphism Through the respiration performed by plants and animals. Through the decay of animal and plant matter. Through combustion of organic material which oxidizes the carbon it contains. Production of cement. At the surface of the oceans where the water becomes warmer, dissolved carbon dioxide is released back into the atmosphere. Volcanic eruptions and metamorphism release gases into the atmosphere.

Carbon is taken from the atmosphere in several ways Photosynthesis. The oceans when the seawater becomes cooler, more CO2 dissolve and become carbonic acid. In the upper ocean areas organisms convert reduced carbon to tissues, or carbonates.

Photosynthesis CO2 + H2O + sunlight  CH2O + O2

Respiration CH2O + O2  CO2 + H2O + energy

Combustion or Oxidization of hydrocarbon CH4 + 2 O2  CO2 + 2 H2O + energy

Human Impacts on the Carbon Cycle Burning fossil fuels have serious impact on the carbon cycle.

Fossil Fuel 86% of global primary energy consumption is fossil fuels.

Fossil Fuels Petroleum Natural Gas Coal

CO2 Concentration Pre-Industrial value: 280 ppm (600 billion tons) Current value: 380 ppm (800 billion tons) Critical value: 560 ppm (1200 billion tons)

Keeling Curve The Keeling Curve shows a cyclic variation of about 5 ppmv in each year corresponding to the seasonal change in uptake of CO2 . How can you explain this ? Most of our world’s vegetation is in the Northern hemisphere, since this is where most of the land is located. During winter in the northern hemisphere, photosynthesis ceases when many plants lose their leaves, but respiration continues. This condition leads to an increase in atmospheric CO2 concentrations during the northern hemisphere winter. With the onset of spring, however, photosynthesis resumes and plants start to intake the CO2, therefore the atmospheric CO2 concentrations are reduced.