1 Energy flow in an ecosystemChapter 3.

2 Food Web in the AntarcticHumans Blue whale Sperm whale Killer whale Elephant seal Crabeater seal Leopard seal Adélie penguins Emperor penguin Petrel Fish Squid Carnivorous plankton Herbivorous zooplankton Krill Phytoplankton Fig. 3-17, p. 48

3 Energy Flow in an EcosystemBiomass Ecological efficiency Pyramid of energy flow

4 Pyramid of Energy Flow Fig. 3-18, p. 49 Heat Heat Decomposers Tertiaryconsumers (human) Heat 10 100 1,000 10,000 Usable energy available at each tropic level (in kilocalories) Secondary consumers (perch) Heat Primary consumers (zooplankton) Heat Producers (phytoplankton) Fig. 3-18, p. 49

5 Biomass Productivity Gross primary productivity (GPP)Net primary productivity (NPP) NPP and populations

6 Differences between GPP and NPPSun Photosynthesis Energy lost and unavailable to consumers Respiration Gross primary production Net primary production (energy available to consumers) Growth and reproduction Fig. 3-19, p. 49

7 Net Primary Productivity in Major Life Zones and EcosystemsTerrestrial Ecosystems Swamps and marshes Tropical rain forest Temperate forest Northern coniferous forest (taiga) Savanna Agricultural land Woodland and shrubland Temperate grassland Tundra (arctic and alpine) Desert scrub Extreme desert Aquatic Ecosystems Estuaries Lakes and streams Continental shelf Open ocean 800 1,600 2,400 3,200 4,000 4,800 5,600 6,400 7,200 8,000 8,800 9,600 Average net primary productivity (kcal/m2/yr) Fig. 3-20, p. 50