Biogeochemical CyclesBiogeochemical Cyclesandand

Energy FlowEnergy Flow

Two Secrets of Survival: Energy Flow Two Secrets of Survival: Energy Flow and Matter Recycleand Matter Recycle

An ecosystem An ecosystem survives by a survives by a combination of combination of energy flow and energy flow and matter recycling.matter recycling.

Figure 3-14Figure 3-14

Fig. 3-14, p. 61

Abiotic chemicals(carbon dioxide,

oxygen, nitrogen, minerals)

Heat

Heat

Heat

Heat

Heat Solarenergy

Consumers(herbivores, carnivores)

Producers(plants)

Decomposers(bacteria, fungi)

The Water CycleThe Water Cycle

Figure 3-26Figure 3-26

Fig. 3-26, p. 72

PrecipitationPrecipitation

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

RunoffSurface runoff

(rapid)

Surface runoff (rapid)

The Carbon Cycle:The Carbon Cycle:Part of Nature’s ThermostatPart of Nature’s Thermostat

Effects of Human Activities Effects of Human Activities on Carbon Cycleon Carbon Cycle

We alter the We alter the carbon cycle by carbon cycle by adding excess COadding excess CO22 to the atmosphere to the atmosphere through:through: Burning fossil fuels.Burning fossil fuels. Clearing vegetation Clearing vegetation

faster than it is faster than it is replaced.replaced.

Figure 3-28Figure 3-28

Fig. 3-28, p. 74

CO

2 em

issi

on

s fr

om

fo

ssil

fu

els

(bil

lio

n m

etri

c to

ns

of

carb

on

eq

uiv

alen

t)

Year

Lowprojection

Highprojection

The Nitrogen Cycle: The Nitrogen Cycle: Bacteria in ActionBacteria in Action

Figure 3-29Figure 3-29

Fig. 3-29, p. 75

Gaseous nitrogen (N2)in atmosphere

Ammonia, ammonium in soil Nitrogen-rich wastes,remains in soil

Nitrate in soil

Loss byleaching

Loss byleaching

Nitrite in soil

Nitrification

Nitrification

Ammonification

Uptake by autotrophsUptake by autotrophsExcretion, death,

decomposition

Loss bydenitrification

Food webs on land

Fertilizers

Nitrogen fixation

The Phosphorous CycleThe Phosphorous Cycle

Figure 3-31Figure 3-31

Fig. 3-31, p. 77

Dissolvedin Ocean

Water

Marine Sediments Rocks

uplifting overgeologic time

settling out weatheringsedimentation

LandFoodWebs

Dissolvedin Soil Water,Lakes, Rivers

death,decomposition

uptake byautotrophs

agriculture

leaching, runoff

uptake byautotrophs

excretion

death,decomposition

mining Fertilizer

weathering

Guano

MarineFoodWebs

Food ChainFood Chain

Food WebFood Web

Ecological PyramidsEcological Pyramids

Ecological PyramidsEcological Pyramids

Ecological PyramidsEcological Pyramids