Salinity
- the total amount of salt dissolved in seawater
- greater salinity in partially enclosed seas
average salinity of ocean
35 parts per thousand
rule of constant proportions
- states that the relative amounts of the various ions in seawater are always the same
-implies that most of the world ocean is well mixed
Critically important dissolved compounds
1) Nitrogen
2) Phosphorous
3) Iron
Salinity, Temperature, Density
lower temperature = more dense
greater salinity = greater density
a profile
a plot that shows temperature, salinity, or any other characteristic of seawater at various depths in the water column.
CTDs
- "conductivity-temperature-depth meters"
- widely used to measure salinity and temperature measurements at different depth in the water column.
Most important gases in ocean
1) oxygen
2) carbon dioxide ( more than 80% of the dissolved gasses in the ocean)
3) nitrogen
gas exchange
the dissolving of gasses from the atmosphere into the ocean, and vice versa
Coriolis effect
-an explanation for how anything that moves over its surface tends to turn a little rather than moving in a straight line
-in Northern Hemisphere, objects deflect toward the right
-in Southern Hemisphere, objects deflect toward the left.
trade winds
- winds that form around the equator
- approach the equator at a 45 degree angle
- over ocean, they are the steadiest winds on earth
- heavily driven by solar energy
the westerlies
- driven by solar energy
- lie at middle latitudes
- move in opposite directions from the trade winds
polar easterlies
- located at high latitudes
- most variable of winds
main wind patterns
1) trade winds
2) westerlies
3) polar easterlies
Ekman spiral
- the process of how currents move
- surface currents move off at a 45 degree angle via Coriolis effect, but the layers underneath move slightly more to the right than those above it and at a slower pace.
Ekman layer
- the upper part of the water column that is affected by the wind
Ekman transport
describes the nature of a whole ekman layer to move at 90 degrees from the wind direction
Gyres
-large circular systems of surface currents
- regulate earth's climate by transporting heat from tropical to polar regions
-greatly affect geographic distribution of organism in the ocean.
surface layer
-usually around 100 to 200 m deep
-mixed by winds, waves, and currents
-very upper layer heated by sun
thermoclines
-the sudden changes in temperature over small depth intervals
-frequently break down
intermediate layer
-lies below surface layer
- around 1,000 - 1,500
-contains the main thermocline
Main thermocline
-a transition zone between warm surface water and cold water below
- breaks down only on occasion and then only in a few places
deep/bottom layer
- below 1,500 m
- uniformly cold ( usually below 4 degrees Celsius)
overturn
when the surface water becomes more dense and sinks, thus displacing/mixing with deeper water
-in profiles, shown as a straight lined areas
the Great Ocean Conveyor
- global thermohaline circulation that mixes the oceans on a timescale of about 4,000 years
-critical in regulating the earth's climate
-brings dissolved oxygen to deep sea
-varies in strength and position ( not constant)
thermohaline circulation
-circulation driven by changes in density, which is determined by temperature and salinity
El Nino- Southern Oscillation
the best know superimposed oscillations
the fetch
-the span of open water over which the wind blows
- affects the size of the wave
seas
- when the wind pushes up the crests and spreads out the troughs
swells
-waves that are away from the wind
-have smoothly rounded crests and troughs
wave cancellation
- when the crest of one wave meets the trough of another and the end up canceling each other
wave reinforcement
-when the crests of two waves collide, resulting in a larger/higher wave than before
tides
-the rhythmic pattern for the falling/rising of the sea surface
-submerge/expose organisms on shore, drive circulation of bays and estuaries, trigger spawning
- heavy influence on marine organisms
cause of tides
-gravitational pull of moon and sun on the earth and the rotations of the earth, moon, and sun.
-water bulges at closest part to moon and farthest point from moon
tidal range
-difference in water level between successive high and low tides
Spring tides
-when the sun and moon are in line with each other
- largest tidal range
- greatest bulges
Neap tides
- when the sun and moon are at right angles to each other ( thus effects partially cancel out)
- small tidal range
Types of tides
1) semi-diurnal tides
2) mixed semi-diurnal tides
3) diurnal tides
semi-diurnal tides
- means there are 2 high tides and 2 low tides every day
- common on east coast of North America and Most of Europe and Africa
mixed semi-diurnal tides
-successive high tides of different heights
-common in west coast of US and Canada
diurnal waves
-only 1 high and 1 low tide a day
-very uncommon
-really only happens in Antarctica and Gulf Coast