ocean Flashcards
how much of the earth’s surface does the ocean cover
70%
how many oceans are there and how many basics
1 ocean with 5 basins (atlantic, pacific, indian, southern, arctic)
what light penetrates deepest into the ocean
blue light penetrates deeper than red light
the 3 ocean layers
sunlight zone, twilight zone, midnight zone
sunlight zone
is the surface layer also known as the euphotic or epipelagic zon, or the mixed layer. the upper 200 meters of the ocean. important layer for photosynthesis with enough sunlight and 90% of all marine life live here.
twilight zone
also known as the mesopelagic or dysphotic zone. little light penetration, 200-1000m. little photosynthesis occurs here
midnight zone
also known as the bathpelagic or aphotic zone. receives no sunlight, little light penetration from bioluminescent organisms. unusual organisms can survive in this, dark, harsh and high pressure environment
what are of the earth gets the most sunlight
the sun shines directly at the equator and tropics where most of the solar energy gets absorbed.
3 temperature layers
mixed layer, transition layer, deep layer
mixed layer
the temperature varies according to season and latitude. wind, waves, tides and convection mix this layer. the sun warms up this layer
transition layer
the temperature rapidly changes. also known as pycnocline, thermocline, or halocline.
deep layer
temperature is cool and about the same temp all the time
sunlight zone (surface of ocean) temp at high lats (polar)
as cold as -2, ocean water freezes at -194 so sea ice forms at high lats
sunlight zone temp at low latitudes (tropics)
as warm as 36
thermocline
layer of water where temperature changes rapidly with depth, also known as the transition layer (twilight zone area). separates warm surface water with the cool deep water. depth and strength of thermocline varies with season and lat. strongest at the tropics and nonexistent at the poles. found in low lats
thermocline seasonal variations in winter
weather/climate cold and stormy, no thermocline and layers well mixed
thermocline seasonal variations in spring
weather/climate is warming, reduced wind. reducsed mixing and thermocline is growing
thermocline seasonal variations in summer
weather/climate warmest and low wind. no mixing and a strong thermocline
thermocline seasonal variations in autumn
weather/climate cooling, increasing wind. thermocline decays and mixing begins
the densest water
cold, salty water
thermocline changes with latitude
the closer to the equator the more pronounced the thermocline is.
composition of seawater
96.5% water. 3.5% salt (made up of chloride, sodium, sulfate, magnesium, calcium, potassium and other minor constituents)
salinity
the mass of dissolved salt in water. most salt in the ocean comes from water running over rocks containing salt carrying it to sea
salinity reduced by
rainfall (tropics and mid lats) and river runoff adding large amounts of water changing the concentration