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.