Nutrient Cycles

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Nutrient Cycles how Humans impact nutrient
cycling

• Bio1

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Where do energy nutrients come from?
What are nutrients? What else do organisms need
to survive and grow? Organisms need _______,
______, and a number of key elements like
_______, _______, ________, and _________. How
do organisms get all of the above?
Energy
water
carbon
oxygen
hydrogen
nitrogen
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Energy Flows, Nutrients Cycle
Energy enters the biosphere continually from
_________. However, all the water and matter (the
stuff) organisms need to survive already exists
in the biosphere -- it simply gets ______ over
and over. If the water matter we need to live
wasnt ________, we would eventually run out. We
have no other source of these things entering the
biosphere. So the recycling of matter is very
important. How does matter get recycled? A
variety of ways
the SUN
reused
recycled
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The Water Cycle
Atmospheric water vapor (13)
condensation
condensation
Water content of oceans (1,380,000)
Water content of sedimentary rocks near earths
surface (210,000)
s in parentheses indicate amount of water as
billion billion (1018) grams/yr
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Water Cycles Through the Biosphere

• 1a Liquid water in rivers, lakes oceans
  evaporates as it turns into water vapor (gas).
• 1b Water vapor is also released from plants
  during transpiration.
• 2 Water vapor in atmosphere condenses to form
  clouds (liquid again).
• 3 Water returns to earth during precipitation.
• 4 Precipitation over land may runoff into bodies
  of water or infiltrate the soil and percolate
  into the ground to become groundwater (which is
  stored in aquifers).
• 5 Water in ground is absorbed by plants through
  roots. Surface water groundwater flows to
  ocean.
• Now go back to the beginning

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Water Cycle is Affected by Human Action

• Clearing vegetation from land for agriculture,
  mining, road building construction often
  increases runoff and can reduce infiltration that
  recharges underground water supplies
• Use of groundwater for irrigation increases
  evaporation over land and depletes groundwater
  supplies (aquifer depletion).
• Ex) Ogallala aquifer (worlds largest known
  aquifer)
• Found under parts of WY, SD, NE, KA, CO, OK, NM,
  TX
• Used to irrigate vast areas of arid high-plains
  prairie into one of largest, most-productive
  agricultural regions in US (produces 1/5 of US
  agricultural output)
• In some areas, water is being pumped out 8-10
  times faster than the (slow) natural recharge
  rate

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Ogallala Aquifer
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Carbon Cycle
Decomposers (bacteria in soil others)
Dead Plants and Animals
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Carbon From Air to Organism

• Carbon dioxide (CO2) in air is used by ______
  during _____________.
• Carbon moves from CO2 in atmosphere into sugars
  in plants.

plants
photosynthesis
CO2 H2O sunlight --gt
C6H12O6 O2
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Carbon From Organism to Air

• Organic compounds (like C6H12O6) in plants,
  animals and microbes are used (burned) as an
  energy source. This process, which organisms
  carry out to release energy from their food, is
  called __________________.
• As part of this process, waste ____ is released.

cellular respiration
C6H12O6 O2 --gt
CO2 H2O ATP (chemical energy)
CO2
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Other Ways Carbon Circulates (including Human
Impact)
http//www.rspbliverpool.org.uk/joint20coach20tr
ips.htm

• Burning of forests or other organic matter
  releases CO and CO2 into the atmosphere.
• Burning of fossil fuels (_____, ___, __________)
  for industry, transportation, and municipal
  energy production also releases CO and CO2.
• Anaerobic bacteria (like those in mammalian
  digestive systems) produce _____________ (CH4) as
  a byproduct of their metabolism.

oil
coal
petroleum
methane gas
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Carbon Cycle
Decomposers (bacteria in soil others)
Dead Plants and Animals
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Nitrogen Cycle
Ammonia (NH3) taken in by legumes
Dead Plants Animals
Decomposers
Ammonia (NH3)
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Nitrogen From Air to Soil

• Why do organisms need nitrogen?
• Molecular nitrogen gas (N2) in atmosphere not
  directly usable by most organisms
• 1 ________________ bacteria in legume root
  nodules and in soil fix nitrogen, converting N2
  into ammonia (NH3)

Nitrogen-fixing
Clover root nodules inhabited by Rhizobium
bacteria
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Nitrogen From Soil to Plant

• 2 Some ammonia in soil is used directly by
  plants (absorbed through roots) to make
  _____________, but many plants still cannot use
  this form of nitrogen.
• 3 Most ammonia in soil is converted to nitrite
  (NO2-) and then nitrate (NO3-) by _________
  bacteria.
• 4 Nitrate (NO3-) is the form of nitrogen that
  most plants can absorb (through roots) and use to
  make _____________.

plant proteins
nitrifying
plant proteins
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Nitrogen From Plant to Animal to Soil Again!

• 5 Animals get their nitrogen by
  ____________________________ .
• 6 Plants animals die, are broken down by
  _____________ bacteria, producing
  ________________ in the soil again.
• Guess what can happen to this _____ now?

eating plants and other animals
decomposing
ammonia (NH3)
NH3
can be assimilated (taken in used) by Plants
to make Proteins can be used by Nitrifying
Bacteria converted to Nitrate
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Nitrogen From Soil to Air again

• 7 __________ bacteria in soil convert nitrites
  nitrates to molecular nitrogen gas
• This is especially true in low O2 conditions
• Implications for farmers?

Denitrifying
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Other Factors in the Nitrogen Cycle

• Nitrogen fixation also occurs in some amount due
  to lightening strikes
• Nitrogen compounds also released into atmosphere
  by volcanoes

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Nitrogen Cycle
Dead Plants Animals
Decomposers
Ammonia (NH3)
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Human Effects on Nitrogen Cycle

• Nitrogen oxides emitted from the combustion of
  fossil fuels (from industry, transportation)
• Excess nitrogen compounds released into
  environment via improper disposal of livestock
  waste/manure (think pig poop) or even untreated
  human sewage
• Nitrate and phosphate-rich fertilizers used
  heavily in agriculture gt can lead to
  ______________ (enrichment of a previously
  limiting nutrient) of freshwater ecosystems due
  to fertilizer-contaminated runoff from farmland.
  Whats so bad about this? Lets see

eutrophication
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Eutrophication as a process
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Eutrophication Effects (in pictures)
Also check out http//en.wikipedia.org/wiki/Eutr
ophication
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Phosphorus Cycle