Salinity, Temperature, Density

• ↓ temp = ↑ density

• ↑ salinity = ↑ densit

• Thermocline– Zone of rapid temp

decrease – Does this correlate with

density and salinity?

Below the surface waters (>500m) it is cold, dense, and saline.Surface water is effected by wind, currents, latitude, and land masses.

Colder at the poles; warmer at the equator (upto nearly 30 C)

Gas

• O, CO2, N• Dissolve better in ↓ temp• ↑ gas concentrations at poles• O not very soluble; .4-.6%

– Compared to 21% in air

• CO2 is more soluble; 80%– Compared to .04% in air– Ocean stores 50x more CO2 than air

Light• Blue wavelengths

penetrate the furthest• Suspended and dissolved

particles affect penetration– Coastal waters absorb some

blue• Appear more green

Pressure• 1 atm = the weight of all the

air above• Every 10m of water depth

adds 1 atm• Increases gas compression (↑ gas density = ↓ gas volume)…not so good for swim bladders

Surface Circulation• Wind drives currents• Both are driven by

sun/heat• Both are affected by

Coriolis effect– Curved path due to

earth’s rotation• N of Equ. deflects to the

right• S of Equ. deflects to the

left

Wind

• Driven by heat↑ temp = ↓ density…air rises…air from higher

latitudes move in placemaking wind…bent by coriolis effect

• Northeast trades• Westerlies

• Wind pushes surface water…bent by Coriolis, too

• Together gyres are produced– Large circular surface current systems– Move heat from equ. to higher latitudes

• Wind causes waves, too.

• Floating objects move in circles rather than following the wave

• Wind pushes surface water• Wave settles into circular swells• Waves nearing shore run out of space for

circular motion…piles up…crashes

Tides• Recurring rise and fall

of sea surface caused by gravitational pull & rotation

• Moons gravity pulls water towards moon

• ↓ gravitational pull on opposite side is not enough to counter the outward inertia of earth’s rotation

• Earth rotation = 24 h– High tide @ bulge– 2 highs & 2 lows in a

24 hr period• Moon has own orbit

– Therefore, full tidal cycle = 24 hrs, 50 min.

• Sun also has gravitation pull…its larger mass would = much stronger pull, but its much further away…therefore half the pull of the moon

• When both are aligned with earth, grav. pull is additive = higher highs & lower lows = spring tides

• Diurnal = daily; once in 24 hours• Semi = half; semidiurnal = _____

– US east coast• US west coast has mixed or variable high & low

tides every half day…due to effects of bottom topography and other land masses