Transcript Lecture 13
Ecology: Biogeochemical Cycles study of the interaction between abiotic and biotic components of…… Energy • Energy passes through biological systems – Organisms transmit energy through food chains/webs – 2nd Law of Thermodynamics means that organisms that feed higher on the food chain have less energy available to them • Therefore, as we move up food chain there is less and less energy and thus biomass Movement of Matter • We’ve discussed energy movement but we also must discuss matter movement. • Matter is anything that has mass and occupies space. – The matter that we observe most commonly takes the form of compounds, polymers, alloys, or pure elements. • Unlike photosynthetic organism which make their own chemical energy, non-photosynthetic organisms must use other energy transport mechanisms (e.g. conduction and convection) to gather matter. • The food that they eat contains matter, but does matter move through food webs the same way that energy does? Answer: Yes and No • Matter from one organism is moved and converted into matter in another organism in much the same was as we saw energy move in the food chain. • If grass obtained it’s energy from the sun, where did it acquire it’s matter from? Direction of Matter Flow Matter to Matter • Where is the matter? • CO2 H20 C6H12O6 O2 • Where does it come from? • Atmosphere Light energy Carbon dioxide Water Photosynthesis Glucose Oxygen gas Where does atmosphere get CO2? • Respiration of living animal • Respiration of plants • But where did it come from? • Well, a better question to ask may be, where did Carbon or Oxygen come from? Estimated major stores of carbon on the Earth. Sink Atmosphere Soil Organic Matter Ocean Marine Sediments and Sedimentary Rocks Terrestrial Plants Fossil Fuel Deposits Amount in Billions of Metric Tons 578 (as of 1700) - 766 (as of 1999) 1500 to 1600 38,000 to 40,000 66,000,000 to 100,000,000 540 to 610 4000 Energy and Elements within a biological system Oxygen Cycle Largely tied to the carbon cycle Generalized scheme for biogeochemical cycles Consumers Producers Detritivores Nutrients available to producers Abiotic reservoir Geologic processes Other biologically important cycles • • • • • Nitrogen Phosphorous Hydrogen Sulfur etc. These are the basic elemental building blocks of biological organisms (CHONPS) Nitrogen Cycle Atmospheric N2 Denitrifying bacteria Nitrogen fixing bacteria Soil Nitrogen Clays, rocks, sediment Detritivores Plants Consumers What you should be able to do: • Trace the flow of energy and/or matter through food webs and biogeochemical cycles. • Identify what happens to pools of matter when rates of change between pools change. • Explain the effects (actual and potential) of man made changes in these rates. • Identify and explain the biological, geological and chemical processes important to the Carbon and Nitrogen cycles.