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ECOSYSTEMS : Cycles. Biochemical Cycling. Cycling of nutrients called biogeochemical cycling Move nutrients from nonliving world to living organisms and back. Without recycling, life could not exist Four biogeochemical cycles Carbon - Nitrogen

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Presentation Transcript
ecosystems cycles


biochemical cycling
Biochemical Cycling
  • Cycling of nutrients called biogeochemical cycling
  • Move nutrients from nonliving world to living organisms and back.
  • Without recycling, life could not exist
  • Four biogeochemical cycles
    • Carbon - Nitrogen
    • Oxygen - Phosphorus

carbon cycling
Carbon Cycling
  • Photosynthesis – removes carbon dioxide from the atmosphere and turns it into biomass.
  • Respiration – returns carbon dioxide to the atmosphere when food is burned by cells.
  • Carbon is also returned to the environment when an organism dies through the action of detrivores.
carbon cycling1
Carbon Cycling
  • Some organisms die and accumulate.
  • Forms large layers of limestone rock
    • Store carbon in rocks for millions years
  • Known as carbon reservoir
  • Weathering returns carbon into atmosphere
  • Volcanic eruptions add carbon dioxide to atmosphere
carbon cycling2
Carbon Cycling
  • Alternate path—plants and animals are buried
  • Exposed to heat and pressure beneath

Earth’s surface

  • Causes chemical changes
  • Produces fossil fuels—oil and coal
    • Oil—once living plankton
    • Coal—remains of plants buried in swamps

carbon cycling3
Carbon Cycling
  • Fossil fuels known as hydrocarbons
      • Composed of hydrogen and carbon
  • Burning returns to atmosphere as carbon dioxide

carbon cycling4
Carbon Cycling
  • Creation of methane gas (CH4)
  • Mud of rice paddies in Asia
    • Anaerobic bacteria release methane gas
  • Cows produce methane in their digestive systems.

oxygen cycling
Oxygen Cycling
  • One of most important interactions
    • Photosynthesis and respiration reactions
    • Photosynthesis consumes carbon dioxide and releases oxygen
    • Used during respiration and carbon dioxide is released
  • Vital link between plants and animals on Earth

oxygen cycling1
Oxygen Cycling

The Earth’s crust is also a reservoir for oxygen storage.

nitrogen cycling nitrification
Nitrogen Cycling - Nitrification
  • Begins with bacteria in soil and roots
  • Combine ammonia with other atoms
  • Nitrogen compounds absorbed by roots of plants
  • Used to make proteins

nitrogen cycling nitrogen fixation
Nitrogen Cycling - Nitrogen Fixation
  • Legumes harbor bacteria that fix nitrogen in small nodules in their roots.
  • Convert atmospheric nitrogen to plant-available nitrogen
  • Used to form proteins and other compounds, which makes nitrogen available to other organisms

Nodules on

Clover roots

nitrogen cycling denitrification
Nitrogen Cycling - Denitrification
  • Bacteria in the soil break down dead organisms, releasing nitrogen gas into the atmosphere.

Denitrification filter,

part of wastewater

treatment plant.

phosphorus cycling
Phosphorus Cycling
  • Major source of phosphorus is not the atmosphere
    • Found in rocks
  • Phosphate-containing rocks become weathered (break down)
  • Main source of phosphorus for ecosystems of Earth

phosphorus cycling1
Phosphorus Cycling
  • Animal wastes contain large amounts of phosphorus
  • Helps to recycle back through food chain
  • Rare in some ecosystems
    • Called a limiting factor

phosphorus cycling2
Phosphorus Cycling
  • Human activity raises phosphorus levels
    • Waste disposal and use of fertilizer
  • Causes rapid growth in aquatic plants and algae

Result is algae bloom

Chokes waterway with overgrowth