Biogeochemical Cycles and Energy Flow

Two Secrets of Survival: Energy Flow and Matter Recycle  An ecosystem survives by a combination of energy flow and matter recycling. Figure 3-14

Fig. 3-14, p. 61 Abiotic chemicals (carbon dioxide, oxygen, nitrogen, minerals) Heat Solar energy Consumers (herbivores, carnivores) Producers (plants) Decomposers (bacteria, fungi)

The Water Cycle Figure 3-26

Fig. 3-26, p. 72 Precipitation Transpiration Condensation Evaporation Ocean storage Transpiration from plants Precipitation to land Groundwater movement (slow) Evaporation from land Evaporation from ocean Precipitation to ocean Infiltration and Percolation Rain clouds Runoff Surface runoff (rapid)

The Carbon Cycle: Part of Nature’s Thermostat

Effects of Human Activities on Carbon Cycle  We alter the carbon cycle by adding excess CO 2 to the atmosphere through: Burning fossil fuels. Burning fossil fuels. Clearing vegetation faster than it is replaced. Clearing vegetation faster than it is replaced. Figure 3-28

Fig. 3-28, p. 74 CO 2 emissions from fossil fuels (billion metric tons of carbon equivalent) Year Low projection High projection

The Nitrogen Cycle: Bacteria in Action Figure 3-29

Fig. 3-29, p. 75 Gaseous nitrogen (N 2 ) in atmosphere Ammonia, ammonium in soil Nitrogen-rich wastes, remains in soil Nitrate in soil Loss by leaching Loss by leaching Nitrite in soil Nitrification Ammonification Uptake by autotrophs Excretion, death, decomposition Loss by denitrification Food webs on land Fertilizers Nitrogen fixation

The Phosphorous Cycle Figure 3-31

Fig. 3-31, p. 77 Dissolved in Ocean Water Marine Sediments Rocks uplifting over geologic time settling out weathering sedimentation Land Food Webs Dissolved in Soil Water, Lakes, Rivers death, decomposition uptake by autotrophs agriculture leaching, runoff uptake by autotrophs excretion death, decomposition miningFertilizer weathering Guano Marine Food Webs

Food Chain

Food Web

Ecological Pyramids