Estuaries

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Estuaries
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Estuaries

• Estuaries are partially enclosed coastal bodies
  of water
• Examples of estuaries include
• River mouths
• Bays
• Inlets
• Gulfs
• Sounds
• Formed by a rise in sea level after the last Ice
  Age

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(No Transcript)
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Southern California Watersheds
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Classifying estuaries by origin

• Coastal plain
• Fjord
• Bar-built
• Tectonic

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Examples of estuaries
Puuloa
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Examples of estuaries
Fjord estuary (Norway)
Tectonic estuary (San Francisco, CA)
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Coastal wetlands

• Coastal wetlands are saturated areas that border
  coastal environments
• Brackish water conditions
• Two most important types of coastal wetlands
• Salt marshes (mid-latitudes)
• Mangrove swamps (low latitudes)

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Coastal wetlands Salt marshes and mangrove swamps
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Salt Marshes are dominated by dense stands of
halophytic (salt-tolerant) plants such as herbs,
grasses, or low shrubs.
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These plants are terrestrial in origin and are
essential to the stability of the salt marsh in
trapping and binding sediments.
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Muddy bottom and sandy bottom communities

• Infauna 
• live within the sediment, mostly soft bottom 
• mostly clams and worms (polychaetes) 
• burrow tubes for food scavenging and oxygen
  supply
• Primary producers algae, mostly benthic diatoms
  and dinoflagellates
• cyanobacteria mats on mudflats
• mud more productive than sand
• macro- and meiobenthos, often detrivores, living
  of deposits from seagrasses and marshes
• birds important grazers

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Muddy bottom and sandy bottom communities
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Muddy bottom and sandy bottom communities

• 32,000 polychaetes in sand/m2
• vs
• 50-500 earth worms in soil/m2
• Ecological Role
• clean sediments
• aerate soil

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Salt marshes

• Found from the Arctic to Southern Australia
• Salt marshes grow in muds and sands that are
  sheltered by barrier islands.
• Flood and ebb currents transport saltwater,
  nutrients, plankton and sediments in and out of
  the marsh.

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Salt marshes play a large role in the aquatic
food web and the exporting of nutrients to
coastal waters.
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They also provide support to terrestrial animals
such as migrating birds as well as providing
coastal protection