Chapter 7: Environmental Systems and Ecosystem Ecology

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Chapter 7 Environmental Systems and Ecosystem
Ecology
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Environmental Systems

• community ecology (different species)
• ecosystem level (living and non-living)
• environmental systems
• solar radiation
• geothermal activity
• organism's metabolism
• human activity
• pollution

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Feedback

• Input parts of a system that causes the
  condition observed
• freshwater
• sediments
• nutrients
• pollution
• Output products obtained from the system
• matter and energy in the form of fish/shellfish

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Feedback loop

• when the output of a system can become the input
• Negative feedback loop input and output
  neutralize each other by dynamic equilibrium
  resulting in homeostasis (stabilized)
• thirst and drinking
• Positive feedback loop drive the ecosystem to
  one of the extremes. Rare in nature but common
  when humans alter the environment
• erosion

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Dead Zone

• area in which oxygen depletion is evident
  (hypoxia)
• normal oxygenated water has 10ppm
• depletion is 2ppm or less
• below 1.5ppm most organisms die
• caused by several factors
• urban runoff
• fertilizers
• municipal sewage
• industrial discharges
• fossil fuel emissions

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Types of Environmental Systems

• lithosphere (rock and sediment)
• atmosphere (air)
• hydrosphere (water systems)
• biosphere (biotic and abiotic)
• they overlap in some way (Ecosystems)

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Ecosystems

• interaction of living and non-living components
• energy (food) is converted into biomass (growth
  and repair)
• nutrients can limit productivity
• too much nitrogen causes dead zone in the gulf
• too much phosphorus causes dead zones in fresh
  water ponds and lakes
• iron seems to be the factor in open ocean waters

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Primary Productivity Worldwide

• Productivity

grams of Carbon per meter squared per year
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Ecosystems Integration

• from small (simple pond) to large scale
  (biosphere)
• adjacent ecosystems may share components
• frogs develop in ponds, live in land and
  reproduce in pond
• salmon lives in the ocean but breeds in
  freshwater
• these areas where ecosystems meet are known as
  ecotones

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Landscape Ecology

• study of different ecosystems that may affect
  abundance, distribution and interaction of
  organisms
• consists of patches and these can be of different
  scales
• subpopulations can live in different patches
• if a species move among patches to mate it is
  called a metapopulation
• metapopulation is used to study loss, protection
  and restoration of biodiversity

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• 5 ecosystems shown in large patches 3
  terrestrial, a marsh and a river
• A corridor is shown between the marsh and the
  forest
• Ecotone is shown between the grassland and forest
  showing patches in a smaller scale

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Geographic Information System (GIS)

• software that takes multiple data
• geology, hydrology, vegetation, animal species,
  human development
• analyzes their location in the area of study
• analyzes their correlation and interactions with
  the other factors

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• GIS integrates different features and human uses
  of an area for future development

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Biochemical Cycles

• carbon cycle
• nitrogen cycle
• water cycle
• phosphorus cycle
• rock cycle
• plate tectonics

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Carbon Cycle

• photosynthesis carbon is fixated in plant growth
• respiration carbon is given back to the
  environment in the form of CO2
• food webs carbon is passed along
• sediment storage remains settle to the bottom of
  the ocean producing fossil fuels
• oceans absorb C from air, runoffs, volcanoes,
  waste and detritus of marine organisms. Ocean
  acidification

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• Carbon Cycle

pool size petagram (1015g) fluxes petagrams of
C per year
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Shifting carbon from lithosphere to atmosphere

• producing more carbon in the air (CO2) by
  combustion than what is put back in the
  lithosphere
• carbon cycle cannot keep up
• cutting down forests and burning fields converts
  that carbon into CO2 releasing it to the air
• 1-2 billion metric tons of CO2 is unaccounted
  for, so it seems it is been taken up by plants
• scientists don't know what ecosystem is doing it
  right now.

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Phosphorus Cycle

• essential for production of DNA, RNA, ATP and
  other molecules essential for life on earth
• present mainly lithosphere and ocean
• humans affect it by extracting it from the
  lithosphere and polluting the ocean with
  fertilizers

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• Phosphorus cycle

pool sizes teragrams (10-12g) fluxes teragrams
of P per year
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Nitrogen Cycle

• 78 of the atmosphere mass as N2
• essential ingredient for DNA and RNA
• essential for plant growth
• N2 is inert but once it transforms into NH3
  (ammonia) or NH4 (ammonium), it becomes "fixed"
• fixed molecules can be taken by plants (nitrogen
  fixation)
• nitrifying bacteria- puts nitrogen back in soil
• denitrifying bacteria- puts nitrogen back in
  atmosphere

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• Nitrogen Cycle

pool sizes teragrams (10-12g) of N fluxes
teragram of N per year
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Human Influence in Nitrogen Cycle

• excess nitrogen from agriculture practices
• causes hypoxia
• dead zone in the gulf
• synthetic ammonia increased food production since
  1950s
• factor in human population growth
• nitrogen fixation has been doubled
• NOx have increased in the atmosphere creating
  nitric acid (acid rain) and nitric oxide (smog)

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• Nitrogen Fixation since 1950

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Hydrologic Cycle

• essential for life
• key role in every cycle already studied
• 97 ocean, 3 fresh water
• carries nutrients
• carries sediments
• distributes pollutants
• evaporation, precipitation, groundwater

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Forms of Fresh Water

• vapor
• evaporation
• transpiration
• liquid
• precipitation
• runoff
• surface water (lakes, rivers)
• groundwater
• aquifers

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• Hydrologic Cycle

pool size cubic kilometers (km3) fluxes km3 per
year
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Impacts on Hydrologic Cycle

• dams increase evaporation
• lake Mead levels
• dams alter vegetation
• Colorado river dams opening
• agricultural fields decrease water level in
  rivers and streams
• Rio Grande
• lower water tables
• Edwards aquifer
• pollutants present in water
• Rio Grande and aquifers
• conflicts for water
• Rio Grande delta, Colorado River

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Geological Systems

• very slow process
• rock cycle
• igneous rock
• sedimentary rock
• metamorphic rock

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Igneous Rock

• form from magma when it cools down
• it formes intrusive rocks
• multicolored
• formed by different similar minerals
• metamorphic and sedimentary
• granite is a good example

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Sedimentary Rock

• formed by sediments and dissolved minerals
• weight and pressure aids its formation
• minerals act like glue
• metamorphic and igneous
• fossils and limestone

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Metamorphic Rock

• changes form due to geological forces
• temperature and pressure
• sedimentary and igneous rock
• marble

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• Tectonic Plates

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• Plate Boundaries

THE END
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