Wetland Ecology

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Wetland Ecology
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Wetlands lands covered with water all or part
of a year

• Hydric (saturated) soils saturated long enough
  to create an anaerobic state in the soil horizon
• Hydrophytic plants adapted to thrive in
  wetlands despite the stresses of an anaerobic and
  flooded environment
• Hydrologic regime dynamic or dominant presence
  of water

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Wetland Classification Chart
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Physical/Hydrological Functions of Wetlands

• Flood Control
• Correlation between wetland loss and downstream
  flooding
• can capture, store, and slowly release water over
  a period of time
• Coastal Protection
• Serve as storm buffers
• Ground Water Recharge
• Water has more time to percolate through the soil
• Sediment Traps
• Wetland plants help to remove sediment from
  flowing water
• Atmospheric Equilibrium
• Can act as sinks for excess carbon and sulfur
• Can return N back to the atmosphere
  (denitrification)

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Chemical Functions of Wetlands

• Pollution Interception
• Nutrient uptake by plants
• Settle in anaerobic soil and become reduced
• Processed by bacterial action
• Toxic Residue Processing
• Buried and neutralized in soils, taken up by
  plants, reduced through ion exchange
• Large-scale / long-term additions can exceed a
  wetlands capacity
• Some chemicals can become more dangerous in
  wetlands (Mercury)

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Mercury Chemistry

• Elememental mercury (Hg0)
• Most common form of environmental mercury
• High vapor pressure, low solubility, does not
  combine with inorganic or organic ligands, not
  available for methylation
• Mercurous Ion (Hg)
• Combines with inorganic compounds only
• Can not be methylated
• Mercuric Ion (Hg)
• Combines with inorganic and organic compounds
• Can be methylated ? CH3HG

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Methylation

• Basically a biological process by microorganisms
  in both sediment and water
• Mono- and dimethylmercury can be formed
• Dimethylmercury is highly volatile and is not
  persistent in aquatic environments
• Influenced by environmnetal variables that affect
  both the availability of mercuric ions for
  methylation and the growth of the methylating
  microbial populations.
• Rates are higher in anoxic environments,
  freshwater, and low pH
• Presence of organic matter can stimulate growth
  of microbial populations, thus enhancing the
  formation of methylmercury (sounds like a swamp
  to me!)

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Methylmercury Bioaccumulation

• Mercury is accumulated by fish, invertebrates,
  mammals, and aquatic plants.
• Inorganic mercury is the dominate environmental
  form of mercury, it is depurated about as fast as
  it is taken up so it does not accumulate.
• Methylmercury can accumulate quickly but
  depurates slowly, so it accumulates
• Also biomagnifies
• Percentage of methylmercury increases with
  organisms age.

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Chemical Functions of Wetlands

• Waste Treatment
• High rate of biological activity
• Can consume a lot of waste
• Heavy deposition of sediments that bury waste
• High level of bacterial activity that breaks down
  and neutralizes waste
• Several cities have begun to use wetlands for
  waste treatment

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Biological Functions of Wetlands

• Biological Production
• 6.4 of the Earths surface ? 24 of total global
  productivity
• Detritus based food webs
• Habitat
• 80 of all breeding bird populations along with
  gt50 of the protected migratory bird species rely
  on wetlands at some point in their life
• 95 of all U.S. commercial fish and shellfish
  species depends on wetlands to some extent

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Wetland Life The Protists

• One celled organisms (algae, bacteria)
• Often have to deal with a lack of oxygen
• Desulfovibrio genus of bacteria that can use
  sulfur, in place of oxygen, as a final electron
  acceptor
• Produces sulfides (rotten-egg smell)
• Other bacteria important in nutrient cycling
• Denitrification

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Phytoplankton

• Single celled
• Base of aquatic food web
• Oxygen production

CO2 H20 ?? H2CO3 ?? H HCO3- ?? 2H CO3 2-
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General Types of Aquatic Macrophytes

• Submergent Plants that grow entirely under
  water. Most are rooted at the bottom and some
  may have flowers that extend above the water
  surface.
• Floating-leaved Plants rooted to the bottom
  with leaves that float on the water surface.
  Flowers are normally above water.
• Free Floating Plants not rooted to the bottom
  and float on the surface.
• Emergent herbaceous or woody plants that have
  the majority of their vegetative parts above the
  surface of the water.

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Coontail
Hydrilla
Parrotfeather
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Floating-Leaved Plants
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Free Floating Plants
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Emergent Plants
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Special Adaptations
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Wetland Trees
Wide at the base Called a buttress
Tupelo
Cypress
Previous Student
I won this boat
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Benefits of Aquatic Plants

• Primary Production
• Wildlife Food
• Oxygen Production
• Shelter
• Protection from predation for small fish
• Fish Spawning
• Several fish attach eggs to aquatic macrophytes
• Some fish build nests in plant beds
• Water Treatment
• Wetland plants are very effective at removing
  nitrogen and phosphorous from polluted waters

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Submerged macrophytes can provide shelter for
young fish as well as house an abundant food
supply.
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Some fish will attach their eggs to aquatic
vegetation.
Alligators also build nests from vegetation.
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• Too many plants can sometimes be a bad thing!
• Block waterways
• Deplete Oxygen