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27 Cards in this Set
- Front
- Back
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What is the chemical composition of seawater?
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Solution of: dissolved salts, gases, elements derived from exchanges with atmospheric, lithospheric & biospheric sources
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What are the most common dissolved ions?
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Chlorine, sodium
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What is the average salinity of the ocean?
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3.5%, or 35ppm (varies near the coasts)
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What are the three oceanic zones?
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2%Mixing (aka photic zone-top layer, warmer, contains plankton)
18%Thermocline (declining temp, less mixture) 80%Deep cold (near freezing, very salty, little oxygen) |
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Which ocean is the largest and deepest?
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The Pacific (avg depth=4000m)
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Why is water saltier in polar areas?
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Glaciers freeze and exclude salt
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What are the five inputs to coastal environments?
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Solar energy (drives winds & weather)
Winds (create currents, waves) Climate regime (moisture, insolation) Coastal substrate (rock, sand, gravel, mud) Human activities (increasingly affect coast) |
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What is the Littoral Zone?
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The coast, from the highest tide down to the depth where storm waves "feel" the bottom
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How is Mean Sea Level calculated?
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Avg tidal level at one spot over a 19-year tidal cycle. Affected by tides, waves, storm surges.
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Describe Spring and Neap tides
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Spring=strong, highest difference betw. high & low tides, sun & moon in same plane.
Neap=weak, smallest difference betw. high & low tides, sun & moon @ 90 degrees. (Spring=new moon, Neap=quarter moon) |
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How are waves produced?
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By wind friction on the ocean's surface.
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What is wave refraction?
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The bending of waves around rocky headlands & submerged rocks.
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How is a tsunami/seismic sea wave produced?
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By earthquakes or submarine volcanic eruptions.
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What is the difference between ebb & flood tides?
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Ebb tide=outgoing
Flood tide=incoming |
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What is the progression of wave types from ocean to beach?
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Swells->Breakers
Waves of transition->Waves of translation |
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What is a rip current?
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A backwash of water from the ocean to the beach in a concentrated column. Brief, short, dangerous.
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What is wave interference?
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Interfering trains of waves that can align and dramatically increase wave height.
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How does longshore/littoral drift work?
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Longshore/littoral currents carry large quantities of sand along the beach.
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What are the two types of coastal output processes?
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Erosional & Depositional.
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What landforms do erosional processes create?
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Erosional (rugged) coastlines, sea cliffs, sea caves, sea arches, sea stacks, wave-cut platforms/terraces.
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What landforms do depositional processes create?
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Beaches, barrier spits, bay barriers, lagoons, tombolos, wave-built terraces.
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What is a coral reef?
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A mounded organic buildup of CaCO3. Hugely diverse with symbiotic relationships - spatial heterogeneity - "rainforests of the ocean." Threatened by coral bleaching due to pollution or warming temps.
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What is a jetty/groin?
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A structure built to stop the flow of longshore drift & trap sand. Jetty=rock, groin=wood
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What lifeforms are found in coastal salt marshes?
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Naturally cultivated grasses, fish, crabs, clams - "nurseries of the sea."
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What is a mangrove?
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The southern version of a coastal salt marsh. Tangle of thick roots in tidal muds. Home to baby fish, oysters, snakes, etc.
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Which area of the beach is most suitable for development?
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The backdune.
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What are the three types of coral reef formations?
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Fringing, Barrier, Atoll. Happens gradually after volcano subsides & is eroded.
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