Marine Science

lithosphere

cool, ridged, and brittle crust; 12 plates

what’s the difference between continental and oceanic plates?

continental plates are thicker and less dense, while oceanic plates are thinner and more dense. thus, oceanic plates usually slip under continental plates.

divergent vs. convergent vs. transform

divergent ← →, creates new oceanic crust
convergent → ← creates trenches, volcanic mountain chains, and continental crust (check)
transform →
←

subduction zone

where one plate slips under another at a convergent boundary, resulting in mountain ranges and island arcs

hot spots

a “thin” spot on a plate that can form anywhere on a plate, where magma “pops through” the lithosphere and results in island formation

what are the 5 sources of water on the planet?

comets, meteorites, magma, albedo effects / cooling / precipitation, “the great oxygenation event”

describe global wind patterns

at the equator, more intense sun leads to hot, humid air rising. as it rises, it drops it water and causes high precipitation. as it moves away from the equator, it dries and cools and sinks around 30 N and S. because of the coriolis effect though, in the N hemisphere wind moves R and in the S hemisphere wind moves L. 

what direction does the earth spin?

counterclockwise

what creates the coriolis effect?

Earth's surface rotates around the axis faster at the equator than at the poles

ekman spiral

refers to the pattern of water movement created by each “layer” of water moving at a 45 angle to the layer above it 

ekman transport

there is net water transport 90 to wind direction (to the R in the N, and to the L in the S)

coastal upwelling

the transport of deeper ocean water, cold and nutrient rich, to the surface as the warm surface water is blown offshore by parallel wind and ekman transport

equatorial upwelling

winds blowing parallel to the equator move warm surface water away (ekman transport) and deeper water comes to the surface in its place

what is a gyre and how are they created?

the circular motion of water in the major ocean basins check

what are the two methods of tracking water movement

eulerian (measuring around a fixed point) and lagrangian (following particles in fluid)

eddie

the swirling of fluid created when fluid flows past an obstacle ex. channel islands area

thermohaline circulation

cold water enters ocean in the N atlantic ocean, upwelling in N pacific ocean, and upwelling in indian ocean

what are the properties of dense water vs. non-dense water

dense: cold and salty
not-dense: warm and low salinity

how are tides created?

the gravitational force from the moon (and a little bit the sun) result in a “bulge” on two sides of the planet

when are the lowest and highest tides?

lowest tides occur at full moons and new moons, highest tides occur at quarter moons 

what are the three types of tide cycles?

semidiurnal tides: 2 high, 2 low a day (most common)
diurnal tides: 1 high, 1 low a day
mixed semidiurnal tides: 2 highs of difference heights

what are progressive waves and what are factors that effect them?

wind generated waves; wind velocity, wind direction, fetch (distance)

generally what are the two types of waves

swells (build over long distances) and wind waves (created locally)

contructive interference

when the peaks and troughs of waves combine and effect wave size

why do waves break?

as waves approach the shore, they interact with the seafloor and compress upwards. also, the bottom slows down a bit compared to the top. this height and difference of movement causes the top to fall over and the wave to break.

wave refraction

refers to how wave energy is distributed; points on the shoreline focus wave energy and bays diffuse it

what is distinct about tsunami waves?

tectonic activity, meteorite, landslide cause a massive amount of energy input, creating waves with low amplitudes, long wavelengths, and fast sppeds

moving downward, what are the levels of the ocean

neritic, oceanic, epipelagic, mesopelagic, bathypelagic, abyssalpelagic, hadalpelagic

moving downward, what are the levels of the benthic rock in the ocean

supralittoral, littoral, sublittoral, bathy, abyssal, hadal

what are the levels of the ocean in terms of sunlight?

uphotic zone(0-200 m, recieves PAR wavelengths for photosynthesis), dysphotic (twilight) zone, aphotic (midnight) zone

compensation depth

the depth at which the rate of primary production is equal to the respiration rate, O2 concentration decreases below this point

what are factors the can effect compensation depth?

biomass, turbidity/sediment, amount of sunlight / latitude

pyncnoclines

sharp gradients in water density over depth; thermocline when due to temperature and haloclines when salinity

explain the o2 concentration vs depth graph?

near the surface where there is lots of sunlight, there is a lot of photosynthesis resulting in high o2 concentration. as it gets deeper, there is less photosynthesis and o2 but still respiration consuming o2. at a certain point though, there is less respiration since less biomass +cold water moving up that holds dissolved gases better = slightly higher o2 concentration

What type of plate boundary has resulted in the Mariana Trench, the deepest location in the ocean?

convergent

At which type of boundary are you most likely to see volcanic mountain chains?

convergent

At which type of boundary is the most new oceanic crust created?

divergent

At which type of boundary is the most new continental crust created?

convergent

Why is oceanic crust forced down into the mantle (subducted) at subduction zones along the margins of a continental plate?

oceanic crust is more dense than continental crust

The global conveyor belt is driven by:

cold, salty, dense water sinking in the North Atlantic

In what direction do ocean gyres move in the Southern Hemisphere?

counter-clockwise

why does salinity differ at and around the equator?

At the equator, there is evaporation and rain. The oceans at 30N and 30S do not get much rain, but they are still in warm climates and experience evaporation. So, salinity is higher just above and below the equator because as water evaporates, the salt stays behind and increases the salt concentration (salinity) in the ocean there.