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21 Cards in this Set
- Front
- Back
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what are estuaries, where are they found, characteristics?
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-semi-enclosed embayment
-where river meets ocean (riprarian) |
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values of estuaries?
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-highly productive
-bring nutrients from land to sea -food web support -oxygen -shoreline stabilization/protection -ground water recharge -recreation |
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how are they altered and unappreciated?
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filled in or polluted, harbors, power plants, agriculture, roads
CA greatest loss: 90% wetlands, 75% salt marshes |
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types of estuaries
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-coastal plains: drowned river mouths
-fjords: glacier-carved -bar-built: sediments form lagoons -tectonic: sinking land faults |
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estuarine circulation and tidal flushing
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-seawater more dense, salinity rises when farther from river
-salitinty and temp change daily with tide -freshwater at surface flushing: when all water is replaced |
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how animals deal with changing salinities
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osmoconformers: slow, moving, cannot change surroundings, avoid fluctuation by being far from river
osmoregulators: excrete excess h20, gills take up ions, etc |
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zones
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mudflat, saltmarsh, brackish (wetland), riprarian, upland
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mudflats
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lowest zone, primary producers, algae, bacteria, birds and gastropods
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salt marsh
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halophytes (salt tolerant plants), submerged at high tide, enter food web as detritus or nutrients, eaten by herbivores or bacteria
-pickleweed, cordgrass, saltgrass |
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channels
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mostly marine, always filled with water, link mudflats, nursery for many species (including pelagic)
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brackish
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where fresh and saltwater meet
salinity: 1-29% |
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riprarian
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freshwater creek or river
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upland
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slopes and bluffs, dunes, scrubby vegetation
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pacific flyway
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Many birds
migrate from northern (summer) breeding grounds TO •Southern, winter grounds •Rest & winter in estuaries |
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pollution
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trapped in estuaries, major dumping from river/storm drains, DIOXINS: chlorine, bleaching, paper products... fish --> humans
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DDT
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pesticide
•Brown pelicans, ospreys, bald eagle, peregrine falcon produce thin egg shells •Banned worldwide (1970’s), still used in developing countries (malaria) |
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PCB
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Cool & insulate electrical devices,
strengthen wood & concrete • lowers reproductive fertility, weakens immune systems |
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eutrophication
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dead zones, worst in spring and summer (when things grow), anoxic
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wetland restoration
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Goal of restoration:
–Return degraded marsh to former conditions –Many major projects in Southern California: •Batiquitos Lagoon, Bolsa Chica, Ballona Wetlands •Possible projects: San Diegito, San Elijo, Los Cerritos -remove invasive plants, dredging, replant native species |
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bolsa chica
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cleanup, new nesting areas, full tidal basin, bridges, new inlet
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continuing threats
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housing development, sewage, runoff, nonnative plants/predators/cats!,
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