Nutrient Cycles Nutrients are _________ that are essential to ______ organisms and that are cycled through the ecosystem There are four major nutrient cycles that we will study in this course ______________ chemicals Water living Carbon Nitrogen Phosphorus Water Cycle Describes the motion or circulation of water Water Cycle Water is heated by the sun and ___________ from large bodies of water Water vapour rises into the atmosphere, where it cools and ___________ Clouds form from condensed water vapour Water falls back to earth as __________ Water erodes rocks and picks up other nutrients evaporates rain/snow condenses Carbon Cycle Carbon enters biosphere as _______ created in plants _________________ (more to come later) Organisms release carbon dioxide back to atmosphere Can also release carbon dioxide from burning ____________________ Dead organisms are ____________ into carbon dioxide sugar wood and fossil fuels Photosynthesis decomposed Carbon Cycle Nitrogen Cycle Nitrogen is plentiful in the atmosphere, but most organisms _______ use atmospheric nitrogen The ____________ holding nitrogen together is too strong ______________ can convert atmospheric nitrogen into useable forms cannot Microorganisms triple bond Nitrogen Cycle In terrestrial (land based) ecosystems, soil bacteria convert nitrogen to ____________ which is a useable form of nitrogen In aquatic (water based) ecosystems, cyanobacteria convert nitrogen to _________ which is a useable form of nitrogen Humans can chemically create useable forms of nitrogen in _________ Certain bacteria convert useable nitrogen into unusable ______________ nitrogen ammonium atmospheric factories ammonium Phosphorus Cycle Stored in ___________ Elemental phosphorus is turned into ___________ Humans also produce phosphates in factories We use phosphates as ___________ and ____________ Decomposer return phosphate to _____ lithosphere fertilizers phosphate detergents soils Human Impact on the Cycles Humans can ________ the natural cycling of nutrients We add __________ and ___________ as fertilizers Gets into ___________________ as run off from farms disrupt ammonium phosphate lakes and oceans Human Impact on the Cycles Extra nutrients can _______ ecosystems Excess nitrogen and phosphate cause algae to __________________ kill off grow really fast Human Impact on the Cycles Extra algae cut off _________ into lakes, killing submerged plants Dead plant matter kills off the algae and other plants Bacteria use ________ to decompose dead plants Fish die from _____________ sunlight oxygen lack of oxygen Human Impact on the Cycles ______________ is a process in which nutrient levels in aquatic ecosystems increase, leading to an increase in the population of primary producers Eutrophication