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Photosynthesis and Carbon Cycle Review Reference Lesson 13 in text
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Photosynthesis Photo – Greek meaning “pertaining to light” Synthesis – Greek meaning “putting together” Autotrophs combine light and substances to create sugar (food) for themselves Photo – Greek meaning “pertaining to light” Synthesis – Greek meaning “putting together” Autotrophs combine light and substances to create sugar (food) for themselves
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Microbes Microbes are any microscopic organism Base of marine food webs Very fast growth rate and life cycles More oxygen is produced in the ocean than on continents Microbes are any microscopic organism Base of marine food webs Very fast growth rate and life cycles More oxygen is produced in the ocean than on continents
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Ozone Phytoplankton – plant like microbes Photosynthetic bacteria – Cyanobacteria Oldest fossil found on Earth – 3.5 billion years ago Before this – no oxygen existed on Earth Produced Ozone - a compound found in the upper atmosphere Before this, no organisms could survive on land due to UV light damage Phytoplankton – plant like microbes Photosynthetic bacteria – Cyanobacteria Oldest fossil found on Earth – 3.5 billion years ago Before this – no oxygen existed on Earth Produced Ozone - a compound found in the upper atmosphere Before this, no organisms could survive on land due to UV light damage People are nuts
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Oldest fossils on Earth
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Cyanobacteria
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Photosynthetic Microbes Diatoms Contain chloroplasts Sunlight can penetrate their clear, silica shells Dinoflagellates Contain chloroplasts Can also ingest food (animal –like) Diatoms Contain chloroplasts Sunlight can penetrate their clear, silica shells Dinoflagellates Contain chloroplasts Can also ingest food (animal –like)
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Photosynthesis Occurs in an organelle chloroplast Converts light energy chemical energy 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 Occurs in an organelle chloroplast Converts light energy chemical energy 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2
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Seasonal Photosynthesis The tilt of the Earth and its revolution around the Sun result in seasonal differences in light availability. Therefore, there are seasonal differences in photosynthesis— both on land and in the ocean. Nearly 50% of sun entering our atmosphere is absorbed by oceans The tilt of the Earth and its revolution around the Sun result in seasonal differences in light availability. Therefore, there are seasonal differences in photosynthesis— both on land and in the ocean. Nearly 50% of sun entering our atmosphere is absorbed by oceans
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Photic Zone Sunlight penetrates only about 200 meters (~650 feet) Photosynthesis can only occur in this top layer, called the photic zone. Sunlight penetrates only about 200 meters (~650 feet) Photosynthesis can only occur in this top layer, called the photic zone.
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What else besides light is necessary for photosynthesis?
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Carbon Dioxide One major source of carbon dioxide (CO 2 ) in the ocean is from marine organisms. Living things release CO 2 as a byproduct of respiration. CO 2 is released from decomposers feeding on dead organisms. One major source of carbon dioxide (CO 2 ) in the ocean is from marine organisms. Living things release CO 2 as a byproduct of respiration. CO 2 is released from decomposers feeding on dead organisms.
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Nutrients Necessary nutrients include: Nitrogen Phosphorus Potassium Iron Phytoplankton absorb these directly through their cell membranes 2 sources: Released when living matter decomposes Runoff from land Necessary nutrients include: Nitrogen Phosphorus Potassium Iron Phytoplankton absorb these directly through their cell membranes 2 sources: Released when living matter decomposes Runoff from land
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Chlorophyll and Enzymes Pigments – light absorbing molecules in autotrophs Chlorophyll – primary pigment in chloroplasts Reflects green Absorbs red and blue wavelengths of light Enzymes are proteins found in the membranes of organisms Speed up chemical reactions Especially in Photosynthesis Pigments – light absorbing molecules in autotrophs Chlorophyll – primary pigment in chloroplasts Reflects green Absorbs red and blue wavelengths of light Enzymes are proteins found in the membranes of organisms Speed up chemical reactions Especially in Photosynthesis
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Carbon Cycle Ocean holds >90% of Earth’s Carbon Dioxide In addition to Photosynthesis, also used by molluscs to build their CaCo 3 shells Plants take in CO 2 to make carbohydrates Carbs get passed through food chain Ocean holds >90% of Earth’s Carbon Dioxide In addition to Photosynthesis, also used by molluscs to build their CaCo 3 shells Plants take in CO 2 to make carbohydrates Carbs get passed through food chain
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Carbon Cycle Buried remains of carbon-rich organisms become incorporated into rocks Eventually remains are compressed into fossil fuels Burning fossil fuels release CO 2 into atmosphere Ocean absorbs ~50% released into atmosphere Buried remains of carbon-rich organisms become incorporated into rocks Eventually remains are compressed into fossil fuels Burning fossil fuels release CO 2 into atmosphere Ocean absorbs ~50% released into atmosphere
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Carbon Cycle Sources CO 2 also released by underwater and land volcanoes CO 2 and CH 4 (methane) released through mining and agriculture Carbon released through deforestation CO 2 also released by underwater and land volcanoes CO 2 and CH 4 (methane) released through mining and agriculture Carbon released through deforestation
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Summarize Photosynthesis Sources IngredientsSources Light Carbon Dioxide Nutrients Chlorophyll Enzymes
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Summarize Photosynthesis Sources IngredientsSources LightSun Carbon DioxideRespiration, Decomposition, Undersea Vents and Volcanoes, Breakdown of rocks/shells NutrientsDecomposition Runoff ChlorophyllContained within the phytoplankton EnzymesContained within the phytoplankton
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Carbon Cycle
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