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18 Cards in this Set
- Front
- Back
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Dominant features of estuaries
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- Variable salinity, flushing, salt wedge,mud flats and salt marshes.
- low species diversity - nutrients supplied by inflow - more detritus is produced in estuaries than lakes, but continually lost to sea - temperate climates = salt-water marshes form between high-low tide ... tropics - mangrove swamps fill that niche |
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Variable salinity changes with...
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tides and season. Mediterranean climate = extended summer drought = head of an estuary can be nearly the same as the ocean in salinity due to low flows.
Winter = freshwater can reach mouth because of freshwater run off |
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Euryhaline
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organisms that can tolerate wide salinity range and good at osmotic regulation
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How does salt wedge form
Area called? |
Denser salt water on bottom and freshwater floating on top.
Area called = picnocline |
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Flocculation is
significance? |
coagulation or clumping together of detritus causing it to sink as precipitate at the picnocline
nutrient trap effect occurs at the salt wedge in estuaries |
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Marine fish and freshwater fish live in what conditions?
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Marine fish: live in medium taht is SALTIER than their bodies
Freshwater fish live in conditions that are LESS SALTY than their bodies - they conserve salt by extracting it with their kidneys |
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Species richness is ________
Why? However,! as much as?! |
LOW because brackish waters
HOWEVER THEY ARE VERY PRODUCTIVE, as much as rain forests |
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Differences between estuaries and lakes in terms of productivity:
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estuaries: get food from inflow from river = allochthonous
flocculation allows food particles to be available to zooplankton and filter feeders in benthos - shallow mudflats heated by sun = speed up bacterial process - not a lot of thermal fluctuations due to tidal flushing - many estuaries are eutrophic, highly productive, and supports lots of phytoplankton |
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Vegetation of Estuaries
and within salt marshes: |
Freshwater plants (cattails, bulrushes and riparian) can't survive along edges of estuaries b/c soil is too salty = no riparian vegetation.
================== Zonation lowest elevation: Cord grass (has been invaded by eastern cord grass) where light-footed clapper nests. inundated by water daily west higher elevation: pickleweed and saltgrass usually free of exotic species and because of no riparian, upland vegetation extends to edge of upper salt marsh |
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Life of salt marsh plants
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Long lived perennials with lifespans of up to 50 years
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Interesting about cord grass it is a...
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is a pioneer plant. soil builds up around it, then other plants are able to colonize
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Estuaries and their Salt Marshes and it's state of condition
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75-90% have been destroyed
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Types of estuaries
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- River mouth with brackish lagoons
- Canyon mouth with lagoons of fluctuating salinity - Bay with extensive deepwater habitats and intertidal wetlands - Structural basin with steed watershed, much sedimentation, and hypersaline conditions |
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River mouth estuaries are characterized by:
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- year-round freshwater runoff and occasional flooding
- a cobble or sand bar separating the ocean from lagoon - brackish water when connection to ocean is open. freshwater layer on top when it is closed - brackish (mixohaline)water that has more salinity than fresh - ex: Ventura River estuary - there is little or no salt marsh in this kind of estuary! |
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Canyon mouth estuaries
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- extremely variable flushing rates
- Malibu Lagoon in LA: large steep watershed, rapid runoff, and frequent tidal flushing - Devereux Slough in Santa Barbara: small coastal terrace and foothill drainage with cobble bar separating ocean. when breached, can empty estuary to 0 ppt saline - animal species diversity low, but bird diversity high ~300 - series of incised, parallel canyons that drain a variety of landscapes |
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Bay estuaries
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- large areas of subtidal habitat (bays) and low elevation salt marshes on margins
- ex: newport back bay, san diego, bolsa chica - strong marine influence b/c channels consistently open to the ocean - strong tidal flushing: like inland extension of ocean - presense of eel grass - extensive habitat on shore - clear zonation of plants and vegetation - Tijuana estuary rich fauna (animals and species) attributed because of thorough flushing |
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Structural bay
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-ex : Goleta and Carpinteria
- steep but short watershed - down-faulted or down folded, occasional catastrophic and sedimentation, esp after fire - lack extensive subtidal habitat and lack low elevation marshes - rich fish fauna - INTERMEDIATE ESTUARIES: |
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Function of estuary
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- shoreline protection
- water quality control enhancement and maintenance - food chain support/ nutrient cycling - habitat - values |
