BIOGEOCHEMICAL CYCLES

Sc.912.E.7.1 Analyze the movement of matter and energy through the different biogeochemical cycles, including water and carbon

OBJECTIVES:1.Identify and describe the flow of

nutrients in each biogeochemical cycle.

2.Explain the impact that humans have on the biogeochemical cycles.

3.What happens to energy in an ecosystem?

4.What happens to matter in an ecosystem?

WHAT ARE BIOGEOCHEMICAL CYCLES? Bio= biology, life, play a role in the living organisms. Geo=Earth, rock, land, this refers to non-living processes at work Chemical=molecules, reactions, atoms These pathways are all made of different biological, geological, and chemical processes that help make the world go 'round and life exist on Earth.

5 cycles1. Carbon2. Hydrologic3. Sulfur4. Nitrogen5. Phosphorus

CYCLING OF MATERIALS Matter moves between ecosystems, environments, and organisms Biogeochemical cycling involves Biological, geologic and chemical interactions

Five major cycles: Carbon, Nitrogen, Phosphorus, Sulfur and Water (hydrologic)

WHAT SUSTAINS LIFE ON EARTH?

Solar energy, the cycling of matter, and gravity sustain the earth’s life.

Figure 3-7

TWO SECRETS OF SURVIVAL: ENERGY FLOW AND MATTER RECYCLE

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

Figure 3-14

MATTER CYCLING IN ECOSYSTEMS Nutrient Cycles: Global RecyclingGlobal Cycles recycle nutrients through the earth’s air, land, water, and living organisms.Nutrients are the elements and compounds that organisms need to live, grow, and reproduce.Biogeochemical cycles move these substances through air, water, soil, rock and living organisms.

THE WATER (HYDROLOGIC) CYCLE

WATER’ UNIQUE PROPERTIES There are strong forces of attraction between molecules of water. Water exists as a liquid over a wide temperature range. Liquid water changes temperature slowly. It takes a large amount of energy for water to evaporate. Liquid water can dissolve a variety of compounds. Water expands when it freezes.

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

Runoff

Surface runoff (rapid)

Surface

runoff (rapid)

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.

THE CARBON CYCLE

Fig. 3-27, pp. 72-73

EFFECTS OF HUMAN ACTIVITIES ON CARBON CYCLE

We alter the carbon cycle by adding excess CO2 to the atmosphere through:Burning fossil fuels.Clearing vegetation faster than it is replaced. Figure 3-28

THE NITROGEN CYCLE

EFFECTS OF HUMAN ACTIVITIES ON THE NITROGEN CYCLE We alter the nitrogen cycle by: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 nitrate ions in inorganic fertilizers.Releasing nitrogen into the troposphere through 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 3-30

THE PHOSPHORUS CYCLE

Fig. 3-31, p. 77

Dissolvedin Ocean

Water

Marine Sediments Rocksuplifting 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

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

EFFECTS OF HUMAN ACTIVITIES ON THE SULFUR CYCLE We add sulfur dioxide to the atmosphere by:Burning coal and oilRefining sulfur containing petroleum.Convert sulfur-containing metallic ores into free metals such as copper, lead, and zinc releasing sulfur dioxide into the environment.