Energy flow in an ecosystemEnergy flow in an ecosystem

Chapter 3.Chapter 3.

Humans

Blue whale Sperm whale

Crabeater seal

Killer whale Elephantseal

Leopardseal

Petrel

Fish Squid

Carnivorous plankton

Krill

Phytoplankton

Herbivorouszooplankton

Emperorpenguin

Fig. 3-17, p. 48

Food Web in the AntarcticFood Web in the Antarctic

Adéliepenguins

Energy Flow in an EcosystemEnergy Flow in an Ecosystem

BiomassBiomass

Ecological efficiencyEcological efficiency

Pyramid of energy flowPyramid of energy flow

Fig. 3-18, p. 49

Secondaryconsumers

(perch)

10

100

1,000

10,000Usable energy

available ateach tropic level(in kilocalories)

Heat

Heat

Heat

Heat

Heat

Producers(phytoplankton)

Tertiaryconsumers

(human)

Primaryconsumers

(zooplankton)

Pyramid of Energy FlowPyramid of Energy Flow

Decomposers

Biomass ProductivityBiomass Productivity

Gross primary productivity (GPP)Gross primary productivity (GPP)

Net primary productivity (NPP)Net primary productivity (NPP)

NPP and populationsNPP and populations

Fig. 3-19, p. 49

Energy lost andunavailable toconsumers

Respiration

Growth and reproduction

Sun

Photosynthesis

Gross primaryproduction

Net primaryproduction(energyavailable toconsumers)

Differences between GPP and NPPDifferences between GPP and NPP

Fig. 3-20, p. 50

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 EcosystemsEstuaries

Lakes and streams

Continental shelf

Open ocean

Terrestrial Ecosystems

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)

Net Primary Productivity in Major Life Net Primary Productivity in Major Life Zones and EcosystemsZones and Ecosystems