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Cycles of Matter Biology Water Cycle • Water moves between the Earth’s surface and • • • • the atmosphere The sun provides the energy to drive the cycle Evaporation – water changes from a liquid to a gas Precipitation – water vapor cools and falls to Earth as rain, sleet, or snow Groundwater – layer of water underground Water Cycle • Living organisms move water about… – Carried within bodies (by drinking it or extracting it from food) – During respiration, water is excreted – Water also evaporates from the skin as sweat – Plant roots collect water from the soil • Some is used for photosynthesis • Some is evaporated or transpired from the leaves Water Cycle • What are the 3 phases of water? – Solid • Ex. Glaciers, ice on the surface of a lake or pond – Liquid • Ex. oceans, rivers, streams, lakes – Gas • Ex. Water vapor • Water vapor cannot be seen, but we know that fog and clouds contain it Water Cycle Carbon Cycle • Carbon is an essential part of proteins, fats, and • • • • carbohydrates needed for life Producers take CO2 from the atmosphere Consumers eat the producers to obtain carbon CO2 is released back to the atmosphere during cellular respiration Fossil fuels store carbon that is then released when they are burned Carbon Cycle • Four main reservoirs of carbon: – Atmosphere • Carbon dioxide, carbon monoxide – Terrestrial Biosphere • Includes freshwater, soil – Oceans • Dissolved carbon, living organisms in the ocean – Sediments • Fossil fuels Carbon Cycle • Four processes involved in the carbon cycle: – Biological processes – photosynthesis, respiration & decomposition – Geochemical processes – release of carbon dioxide gas into the atmosphere by volcanoes – Mixed biogeochemical processes – burial of carbon-rich organisms and their conversion to fossil fuels – Human activity – mining, burning of fossil fuels Carbon Cycle Nitrogen Cycle • All organisms need nitrogen to build proteins • Nitrogen gas makes up 78% of the atmosphere • Nitrogen-fixing bacteria – Convert nitrogen from the air into ammonia (nitrogen fixation) Nitrogen Cycle • Ammonia is converted into nitrates and nitrites, which plants and other producers can use (nitrification) • Bacteria convert nitrogen in the soil into atmospheric nitrogen (denitrification) • Decomposers return nitrogen to the soil Nitrogen Cycle