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.
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