Fig. 3-7, p. 55

Nitrogencycle

Biosphere

Heat in the environment

Phosphoruscycle

Carboncycle

Oxygencycle

Watercycle

Ecological Cycles

MATTER CYCLING IN ECOSYSTEMS

• Nutrient Cycles = Global Recycling

– Nutrients are the elements & compounds that organisms need for life

– Cycles substances through air, water, soil, rock and living organisms.

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 Water Cycle

Effects of Human Activities on Water Cycle

• We alter the water cycle by:– Withdrawing large amounts of freshwater.– Clearing vegetation and eroding soils.– Polluting surface and underground water.– Contributing to climate change.

CARBON CYCLE

Effects of Human Activities on Carbon Cycle

• excess CO2 to the atmosphere

– Burning fossil fuels– Clearing vegetation

faster than it is replaced.

Figure 3-28Figure 3-28

Nitrogen Cycle- Bacteria in Action

Effects of Human Activities on the Nitrogen Cycle

– Adding gases that contribute to acid rain.– Adding nitrous oxide to the atmosphere

through farming practices which can warm the atmosphere and deplete ozone.

– Contaminating ground water from inorganic fertilizers.

– Releasing via deforestation.

Effects of Human Activities on the Nitrogen Cycle

• Human activities such as production of fertilizers now fix more nitrogen than all natural sources combined.

Figure 3-30Figure 3-30

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

The Phosphorous Cycle

Effects of Human Activities on the Phosphorous Cycle

• We remove large amounts of phosphate from the earth to make fertilizer.

• We reduce phosphorous in tropical soils by clearing forests.

• We add excess phosphates to aquatic systems from runoff of animal wastes and fertilizers.

Fig. 3-32, p. 78

Hydrogen sulfide

Sulfur

Sulfate salts

Decaying matter

Animals

Plants

Ocean

IndustriesVolcano

Hydrogen sulfideOxygen

Dimethyl sulfide

Ammoniumsulfate

Ammonia

Acidic fog and precipitationSulfuric acid

WaterSulfurtrioxide

Sulfur dioxide

Metallicsulfidedeposits

The Sulfur Cycle

Effects of Human Activities on the Sulfur Cycle

• We add sulfur dioxide to the atmosphere by:– Burning coal and oil– Refining sulfur containing petroleum.– Convert sulfur-containing metallic ores into

free metals such as copper, lead, and zinc releasing sulfur dioxide into the environment.