Ocean characteristics
What is oceanography?
The study of the biology, chemistry, geology, and physics of the ocean.
What is bathymetry?
The topography of the sea floor
How are lithogenous sediments produced?
Weathering processes
What is responsible for the special properties of water?
Water's chemical structure, including its polarity and hydrogen bonding.
Where is surface water salinity lowest?
Near the equator - high precipitation
Latitude greater than 40o - high precipitation and low evaporation
What are the 4 major features of ocean margins?
Continental shelf, shelf break, continental slope, and continental rise
What drives tectonic plate movement?
Convection of the mantle and formation of new crust at the mid-ocean ridges and rises
List the sediment grain sizes from smallest to largest.
Clay < Silt < Sand < Gravel < Cobble < Boulder
How does the presence of salt in seawater change its boiling point and freezing point?
Presence of salt raises the boiling point and lowers the freezing point.
Older water masses have low concentrations of ______ and high concentrations of ______.
Low concentrations of oxygen
High concentrations of nutrients (nitrate and phosphate)
What percentage of water on earth is found in the ocean?
98%
BONUS points: What are the 3 remaining sources of water on earth? (10pts each)
How many major tectonic plates are there?
7
BONUS points: 10pts for each major plate you can name, and 50pts for each minor plate
Which water bodies have the highest sediment accumulation rates?
River deltas
BONUS points: 50 points is you can give the sedimentation rate
What does it mean to say that major ions are conservative?
They have constant ratios, to one another and to salinity, in almost all ocean water.
What type of water mass forms at high latitudes and results in cold, dense water?
Intermediate, deep, and bottom water
BONUS points: 20 points for each example
Is oceanic crust or continental crust denser?
Oceanic crust is denser (3.0 g/cm3) than continental crust (2.7 g/cm3)
BONUS points: Explain why (50pts)
What is the difference between a divergent boundary and a convergent boundary?
Convergent boundary, also called a subduction zone, is where plates collide and oceanic crust is forced underneath another plate.
BONUS points: 50 points for an example of the resulting bathymetry at each boundary.
Sediments consisting of at least 30% of the remains of marine plankton (small marine plants and animals) are termed biogenous oozes. What are the two types of biogenous ooze?
Calcareous and siliceous
BONUS points: 50 points for each example you can provide
Name a process that increases salinity in seawater, and a process that decreases salinity in seawater.
Processes that increase salinity include evaporation and formation of sea ice.
Processes that decrease salinity include precipitation, land runoff, and melting of sea ice
What is the difference between the main thermocline and the seasonal thermocline?
The main thermocline exists year-round and begins at about 100 m, extending below 500 m depth. Its upper boundary corresponds to the depth of mixing in winter.
The seasonal thermocline is shallower (20-50 m depth in most cases), and is present only in warmer months when heating of surface water makes it less dense.
Describe the difference between a passive continental margin and active continental margin.
Passive margins typically consist of a shallow continental shelf and gentle sloping continental slope and are found where no collision or subduction of plates occurs. Active margins are commonly sites of tectonic activity and can be characterized by volcanic activity and deep sea trenches.
BONUS points: 100 pts for an example of a passive and active margin
How do S-waves and P-waves differ, and what does this say about the interior of earth?
S-waves do not travel through liquids, while P-waves do (but are refracted).
Studying these waves shows that the outer core is liquid, while the mantle and inner core are solid.
How can foraminifera tests be used to study ice ages?
Foram tests (shells) in sediments deposited during glacial times are heavier than those deposited today.
The fossil foraminiferans which are found in layers with “heavy” (18O) oxygen isotope composition are species that grew in colder water conditions than those in layers with “light” (16O) oxygen isotope composition.
Sodium ion, chloride, sulfate, magnesium ion, calcium ion, and potassium ion
How can you age water masses?
The age of water masses is the time since they were last at the surface and able to absorb new 14C from the atmosphere.
BONUS points: 100 points for the 14C age of the northern North Pacific