Photosynthesis (performed by plants, algae, and some bacteria) Sun 6 O 6 CO 6 H O C 6 H O 6 (glucose) Solar energy + 6 H O + 6 CO C 6 H O 6 + 6 O Energy Respiration (performed by all organisms) 6 O 6 CO 6 H O C 6 H O 6 Energy + 6 H O + 6 CO C 6 H O 6 + 6 O 0 by W. H. Freeman and Company Figure. Page 6
Tertiary consumers Bald eagle Lion Secondary consumers Fish Zebra Primary consumers Zooplankton Grasses Algae (a) Terrestrial food chain (b) Aquatic food chain 0 by W. H. Freeman and Company Figure. Page 6
Primary consumers Secondary consumers Scavengers Detritivores Vulture Acacia tree Giraffe Gazelle Lion Cheetah Zebra Hyena Wildebeest (dead) Bacteria, fungi Dung-rolling beetle Hare Grasses Earthworm 0 by W. H. Freeman and Company Figure.6 Page 6
Evaporated water condenses into clouds. Evaporation from ocean Evaporation from soil Evapotranspiration from plants Rain clouds Precipitation Water returns to Earth as precipitation (rain, snow, hail). Surface runoff Infiltration Solar energy heats Earth, and causes evaporation. Ocean Groundwater Precipitation falling on land is taken up by plants, runs off along the land surface, or percolates into the soil and enters the groundwater. 0 by W. H. Freeman and Company Figure.0 Page 67
Burial 6 Combustion converts fossil fuels and plant material into CO. Atmospheric CO convert CO into sugars. CO in the atmosphere and CO dissolved in water are constantly exchanged. Exchange Combustion 6 Respiration Photosynthesis Sugars are converted back into CO. Ocean Respiration Dissolved CO Photosynthesis Natural and humancaused fires Human fossil fuel supply Extraction Consumers Consumers Sedimentation Burial Sedimentary rock Fossil fuels (oil, natural gas, coal) Human extraction of fossil fuels brings carbon to Earth s surface, where it can be combusted. Some carbon can be buried. 0 by W. H. Freeman and Company Figure. Page 68
Atmospheric nitrogen (mostly N dinitrogen gas) Lightning and combustion, some industrial fertilizer production Nitrogen fixation N O (Nitrous oxide) Denitrification Nitrogen-fixing bacteria associated with roots, cyanobacteria, industrial fertilizer Consumers production NH (Ammonia) Ammonification Soil Assimilation Leaching Assimilation Nitrification NO (Nitrate) Assimilation NH + (Ammonium) NO (Nitrite) Nitrogen Fixation Assimilation Ammonification Nitrification Denitrification Nitrogen fixation converts N from the atmosphere. Biotic processes convert N to ammonia (NH ), whereas abiotic processes convert N to nitrate (NO ). take up either ammonium (NH + ) or nitrate (NO ). Consumers assimilate nitrogen by eating producers. in soil and water break down biological nitrogen compounds into ammonium (NH + ). Nitrifying bacteria convert ammonium (NH + ) into nitrite (NO ) and then into nitrate (NO ). In a series of steps, denitrifying bacteria in oxygen-poor soil and stagnant water convert nitrate (NO ) into nitrous oxide (N O) and eventually nitrogen gas (N ). 0 by W. H. Freeman and Company Figure. Page 70
Weathering of uplifted rocks contributes phosphates to the land. Some phosphates make their way back to the ocean. Phosphate fertilizer applied to fields can run off directly into streams, become part of a soil pool, or be absorbed by plants. Fertilizer Phosphate mining Detergents, cleaners Phosphate rocks Weathering Geologic forces can slowly lift up phosphate rocks from the ocean floor to form mountains. Plants Soil Direct runoff Geologic uplift Leaching Excretion and decomposition Wastewater flow Animals Ocean Excretion by animals and decomposition of both animals and plants release phosphates on land or in water. Excretion and decomposition Animals Dissolved phosphates Plants and algae Marine sediments Dissolved phosphates precipitate out of solution and contribute to the ocean sediments. Conversion of sediments into phosphate rocks is a very slow process. Phosphate rocks 0 by W. H. Freeman and Company Figure. Page 7