Nutrient CyclingWhat Happens to Matter in an Ecosytem?

Questions for Today:

• How does matter cycle through an Ecosystem?

• How many biogeochemical cycles do Environmental Scientists analyze?

• What are the major key components for each cycle?

• How do humans influence the different biogeochemical cycles?

What happens to Matter?

• The matter and nutrients in our environment move continually through the abiotic and biotic factors in our ecosystem and in the biosphere in cycles called Biogeochemical Cycles.

• Nutrient cycling is one of the four major principles of Sustainability.

What happens to Matter?

• There are 5 major cycles driven by the sun and gravity:– Hydrologic (Water)– Carbon– Nitrogen– Phosphorous– Sulfur

• As nutrients move through the cycle, they can spend the majority of their time in one form.– Reservoirs

Water Cycle

• Water Cycles (WC) collects, purifies, and distributes the earth’s fixed supply of water.

• The WC’s reservoirs are the atmosphere and hydrosphere.– Global Cycle

Water Cycle

• Parts of the WC include:– Evaporation– Condensation– Precipitation– Transpiration

Water Cycle

• After Precipitation, Water can take various paths:– Surface Runoff– Seepage– Glaciers– Aquifers– Groundwater– Absorption

Water Cycle

• Three Major Ways we alter the WC:– We withdraw large amounts of freshwater

• 0.024% of the water on the planets is usable freshwater

– We clear vegetation for building purposes• Increases runoff

• Reduces infiltration

• Increase risk of flooding, soil erosions and landslides

– We increase flooding• When we drain Wetlands for farming or roads

The Water Cycle

Carbon Cycle

• The Carbon Cycle is the Link between photosynthesis in producers and respiration in producers, consumers, and decomposers

• The Reservoir for Carbon is found in the geosphere.

• The Carbon Cycle is based on CO2 gas.

Carbon Cycle

• The Major Parts of the Carbon Cycle are:– Photosynthesis– Cellular Respiration– Deposition– Lithification

• Carbon acts as nature’s thermostat.– Too little CO2 in the air, the temp. goes down

– Too much CO2 in the air, the temp. goes up.

Carbon Cycles

• Humans affect the Carbon Cycle in two ways:– Deforestation– Burning of Fossil Fuels

• Both ways increase the amount of CO2 in the atmosphere.– Computer modeling links CO2 added by

humans have increased earth’s natural greenhouse effect.

Carbon Cycle

Nitrogen Cycle

• The Nitrogen Cycle is important in the creation of proteins and nucleic acids for all living creatures.

• The Major Reservoir for Nitrogen is the atmosphere.– 78% of Nitrogen is found in the Atmosphere

as N2

• Plants and Animals have a hard time absorbing Atmospheric Nitrogen.

Nitrogen Cycle

• Four major parts of the Nitrogen Cycle:– Nitrogen Fixation

• Bacteria• Electrical Discharges

– Nitrification• Biological

– Ammonification• Biological

– Denitrification• Biological

Nitrogen Cycle

• Humans Alter the Nitrogen Cycle in FIVE ways:– Release of Nitric Oxide (NO) into the atmosphere

• Acid Rain

– Addition of N2O, nitrous oxide, through anaerobic bacteria on livestock wastes

• Destroys Ozone

– Deforestation– Fertilizer Runoff– Overharvesting

Nitrogen Cycle

Phosphorous Cycle

• Phosphorous Cycle is important for plant growth and DNA production and Cellular Energy

• Major Reservoir is the Geosphere– NO ATMOSPHERIC PHOSPHOROUS

• Found in the environment as Phosphates.• Really slow process.• Humans affect the Phosphorous Cycle by

overharvesting of Phosphorous from the soil and deforestation.

Phosphorous Cycle

Sulfur Cycle

• Sulfur found in organisms, ocean sediments, soil, rocks, and fossil fuels

• SO2 in the atmosphere• H2SO4 and SO4

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• Human activities affect the sulfur cycle– Burn sulfur-containing coal and oil– Refine sulfur-containing petroleum– Convert sulfur-containing metallic mineral

ores

Sulfur Cycle