Oceanography Flashcards
what is thermocline?
the thermocline is the transition layer between surface layer and bottom layer. (temperature)
what is the halocline?
the halocline is the transition layer between fresh water and salt water
what is the measurement for salinity?
ppt–parts per thousand
what is salinity? how much salt is in the ocean?
salinity is the measure of salt dissolved in water.
3.5% or 35ppt = salinity in ocean
what is upwelling? what does it bring up?
wind blows water and then cold water rises. that water brings up fish and food.
what is downwelling? what does it bring down?
water goes downward. brings down oxygen, food, heat
why does ice float?
ice freezes and then expands. the way ice freezes is water molecules create a 102 degree angle which creates the crystal shape. then the crystal shape causes it to expand. it is less dense than water.
what temperature is water most dense at?
4 degrees Celsius
how can you increase density of sea water?
by taking away fresh water.
evaporation and freezing
how can you decrease the density of sea water?
by adding more fresh water.
water melts from LAND, rain/snow, rivers
what is oceanography?
study/ mapping of the ocean floor
how is the water distributed in the world?
97%=saltwater: oceans
3%=freshwater: ice caps, rivers, lakes, underground
what are 3 ways sea levels change?
temperature, plate tectonics, melting ice
how does temperature affect sea levels?
when temp rises, water expands, sea level rises.
when temp falls, water condenses, seal level falls.
how does plate tectonics affect sea levels?
rising and falling of the sea floor
how does melting ice affect sea levels?
when ice from land masses melt, goes into ocean, level rises.
when ice forms on land, takes away from ocean, level drops
how much of the world is covered by oceans?
71%
list the 5 oceans by size
Pacific, Atlantic, Indian, Antarctic, Arctic
which ocean is shrinking? why?
Pacific; because of subduction zones, the continents are getting pushed together
which ocean is growing? why?
Atlantic; because of mid oceanic ridge, new sea floor
what is the new ocean?
Ethiopian ocean, 10 million years is expected
what are the 3 characteristics a body of water needs to be classified as a sea?
partially/mostly land locked
saltwater
part of water (ocean) circulation
how is water a good buffer?
water stores heat. it absorbs heat during day and releases it at night. this allows for less drastic temp swings
what is a salt? what is most common salt in ocean?
a metal + a non metal
NaCl is most common in ocean
what is the density of sea water?
1.02 - 1.03 g/cm3
how is the density of oceans affected?
by temperature and salinity
how far can light travel in the ocean? and what light goes farthest?
100 meters.
red is absorbed first, blue goes farthest
no surface layer = ?
no thermocline
Gyers do not cross the ___
equator
gyers in the northern hemisphere move ____
gyers in the southern hemishpers move ____
northern= clockwise/right southern= counterclockwise/left
what do gyers move around?
heat
what is the longest mountain ridge on Earth?
the mid Atlantic ridge
where does the hydrothermal vent get its heat?
earth’s mantle/magma
when did oceanography begin and what was the first vessel to explore the ocean floor?
began in late 1800s
The Challenger
ocean temps can very from ___
-2 to 35 degrees Celsius
land temps can vary from ___
-70 to 35 degrees Celsius
Water becomes denser until ___ and then ___
4 degrees C ; expands
In the Pacific, the ridge is ___ faster than new floor created which means the ocean is getting ___
subducting, smaller
what is the salinity in the subtropical and why?
37ppt; increased evaporation increases salt ions
what is the salinity in the tropics and why?
32-33ppt; lots of rain= more fresh water
salt water freezes at ___
-2 degrees Celsius because takes more energy to freeze salt ions
ancient seas and todays seas have same salt levels. how do we know?
evidence found in old and new sea shells and fossils
what creates the densest sea water?
high salinity + cold temp = densest water
water ___, leaves behind ___, cold water sinks beneath ice and becomes ___ and ___, then ___ and migrates to the ___
freezes, salt, saltier, denser, sinks, equator
why do gyers not cross the equator?
because southern and northern hemisphere currents are opposite
where the sea floor drops off quickly?
slope
what is the flattest part of earth?
abyssal plains
