GEOCHEMICAL CYCLES

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GEOCHEMICAL CYCLES LIMITING FACTORS
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Cycles of Matter

• While energy is crucial to an ecosystem, all
  organisms need more than energy to survive
• Water
• Minerals
• Life-sustaining compounds
• For most organisms, more than 95 of the body is
  made up of O, C, H, N
• These common elements cannot be used by
  organisms unless the elements are in a chemical
  form that cells can take up

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Recycling in the Biosphere

• Unlike the one-way flow of energy through an
  ecosystem, matter is recycled within and between
  ecosystems
• Elements, chemical compounds, and matter are
  passed from one organism to another and from one
  part of the biosphere to another through
  biogeochemical cycles
• Biogeochemical cycles pass the same molecules
  around again and again within the biosphere

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Root uptake
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H2O CYCLE- BOOKLET

• Evaporation
• water changes from liquid ?gas
• Transpiration
• Water evaporates from leaves of plants
• Precipitation
• Ex rain, snow, sleet or hail
• Runoff
• The precip runs along the surface of the ground,
  enters a river or stream, carried to an ocean or
  lake

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Nutrient Cycles

• Nutrients are the bodys building blocks
• - Every living organism needs nutrients to grow
  and carry out essential life functions
• Nutrients, like water, are passed between
  organisms and the environment through
  biogeochemical cycles
• Because nutrients are in short supply in many
  ecosystems, recycling of nutrients is essential
  for these ecosystems to keep functioning

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CARBON CYCLE-BOOKLET

• 4 processes involved with the C cycle
• Biological
• ex photosynthesis, respiration and decomposition
• Geochemical
• ex release of CO2 to the atmosphere by volcanoes
• Biogeochemical processes
• ex burial of C rich remains of organisms and
  their conversion into coal and petroleum
• Human activity
• ex mining, burning of fossil fuels and the
  cutting/burning of forests

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The Carbon Cycle
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N2 CYCLE-BOOKLET

• N2 is most abundant, but only certain bacteria in
  the soil and lightning in the atmosphere can
  convert it to a useable form ammonia.
• This conversion is called NITROGEN FIXATION.
• When orgs die, decomposers break down the remains
  and return nitrogen to the soil as ammonia.

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N2 CYCLE-BOOKLET

• If not taken up by plants, other bacteria in the
  soil convert nitrates into nitrogen gas this
  conversion is denitrification. The nitrogen is
  now back in the atmosphere.
• ammonia ?nitrate nitrite ions

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The Nitrogen Cycle
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Phosphorus Cycle

• Phosphorus (P)-important (DNA structure), not
  very common in the biosphere.
• P does NOT enter the atmosphere found mostly in
  rock, mineral form, and ocean sediments.
• P taken up by plants, eaten by consumers.
• In the ocean-used by microorganisms, eaten by
  ocean consumers

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The Phosphorus Cycle
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Nutrient Limitation

• The primary productivity of an ecosystem is the
  rate at which organic matter is created by
  producers
• Factor that control the primary productivity of
  an ecosystem are the amount of available
  nutrients
• Nutrients in short supply will limit an
  organisms growth
• When an ecosystem is limited by a single nutrient
  that is scarce or cycles very slowly, this
  substance is called a limiting nutrient

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Ex. Algal Blooms- aquatic ecosystem

• When an aquatic ecosystem receives a large input
  of a limiting nutrient, the result is often an
  immediate increase in the amount of algae other
  producers
• Leads to algal blooms that cover the surface of
  the water if there are not enough consumers to
  eat the producers, the aquatic ecosystem is upset.