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Ecosystems and Environment Biogeochemical cycles • All materials flow through the environment over time- materials cycle through the environment Energy • Energy flows through the environment • Sunlight to chlorophyll to photosynthesis to sugars to plant biomass to…. • Food chains - energy passes from one organism to another - it is a one way tripenergy passed through the environment in a linear fashion- unlike materials Food chains • Trophic levels • available energy and biomass decrease at each trophic level • Gross primary productivity - rate at which energy is captured and stored in plant tissues • Net primary productivity - energy after plant’s requirements Major ecosystems • Biomes - large distinct ecosystem – – – – – – tundra tiaga or boreal forest temperate rainforest temperate deciduous forest temperate grasslands chaparral Biomes – Deserts – savanna – tropical rainforests Aquatic ecosystems • lakes and ponds – littoral zones - nearest to shore – limnetic zones - open water – profundal zone - no light • marine – – – – – intertidal - very productive pelagic - open ocean euphotic - light is present (100m) neritic - 100m to 200m oceanic - no light Stratification in water • In summer warm layers on top, colder at the bottom, separated by thermocline • in fall, water turns over and some mixing between layers occurs • in winter cold at top, warmer at bottom • in spring another turnover! • Spring turnover stimulates algae growth... Environmental Issues • • • • • • Habitat destruction pollution foreign or exotic species deforestation global warming ozone depletion