- 1. The Waters of the Ocean
2. A. The Unique Nature of Pure Water All matter is made of
atoms Elements are make from one kind of atom A molecule is two or
more different atoms combined Water is a polar molecule; one end is
positivelycharged and the other is negatively charged 3. 1. The
Three States of Water Only substance on Earth to naturally exist in
three states Weak hydrogen bonds form between to the positive
endand the negative end of different water molecules Solid water
molecules pack close together & locked infixed three
dimensional pattern Becomes more dense until about 4C (get less
dense) &expands When water freezes in fresh and marine water
the iceforms on top allowing organisms to live underneath the ice
When marine water freezes it acts like an insulator to stopfreezing
all the water 4. 2. Heat and Water Bonds must be broken before
molecules can begin tomove around Melts at higher temperature &
absorbs a lot of heatwhen it melts (high latent heart of melting)
and greatdeal of heat must be removed to freeze it Melting ice,
added heat breaks more hydrogen bondsthan increasing molecular
motion Mixture of ice & water is 0-adding heat goes intomelting
the ice not raising temperature High heat capacity therefore marine
organisms notaffect by temperature changes in atmosphere &
latentheat of evaporation 5. 3. Water as a Solvent Dissolve more
things than any other naturalsubstance (universal solvent)
especially salts Salts made of opposite charged particles and
conductselectricitySingle atoms or groups of atoms In water, strong
ion charges attract watermolecule, water molecules surround the
ions and pullthem apart (dissociation) 6. B. Seawater
Characteristics due to nature of pure water &materials
dissolved in it Dissolved solids due to chemical weathering of
rockson land & hydrothermal vents 7. 1. Salt CompositionSodium
chloride account for 85% of all solids dissolvedSalinity is total
salt dissolved in seawaternumber of grams left behind when 1000
grams evaporatedif 35 grams left then 35 parts per thousand or
350/00 or 35psu (practical salinity units) Rule of constant
proportions states that the relativeamounts of various ions in
seawater are always the same Differences in salinity results from
removal (evaporation)and addition (precipitation) of water Rarely
have to deal with changes in ratio of ions as resulteasier to
control salt & water balance Average salinity is 35 psu and
between 33-37 psu in openocean Red Sea is 40 psu 7 & Baltic Sea
is 7 psu Why is Red Sea salinity so high and the Baltic Sea so low?
8. 2. Salinity, Temperature, and Density Get denser as it gets
saltier, colder, or both -2 to 30C temps. below zero possible
because saltwater freezesat colder temps. Density controlled more
by temperature than salinity There are exceptions therefore
salinity & temp need tobe measured to determine density 9. 3.
Dissolved Gases O2, CO2 and N2 in atmosphere & sea surface Gas
exchange happens between the surface &atmosphere Dissolved gas
concentration higher in coldwater, lower in warm water Amount of
oxygen in water is affected byphotosynthesis & respiration Most
oxygen is released into the atmosphere More susceptible to oxygen
depletion thanatmosphere 80% of gasses is carbon dioxide 10. 4.
Transparency Sunlight can penetrate, but its affected by
thematerial suspended in the water Important to the photosynthetic
organisms Runoff makes coastal waters less transparent thandeep
blue waters of open ocean 11. 5. Pressure On land, organisms are
under 1 atm at sea level Marine organism have the pressure of the
atmosphere &water With every 10m increase depth another atm is
added As atms increase gases are compressed Organism have air
bladders, floats and lungs that shrinkand collapse Limits depth
range, some organism are injured whenbrought to the surface
Submarines & housing must be specially engineered towithstand
pressure 12. Ocean Circulation Throughout depths currents move and
mix ocean waters and transport heat nutrients, pollutants and
organisms 13. A. Surface circulation Driven by the wind 14. 1. The
Coriolis Effect Because Earth is rotating anything that moves
overthe surface tends to turn a little rather in a straight line
Deflects large-scale motions like winds and currentsto the right in
Northern Hemisphere and to the left inSouthern Hemisphere 15. 2.
Wind Patterns Winds driven by heat energy from sun Trade winds
warmer at equator wind at equator becomes less dense and air
fromadjacent areas gets sucked in to replace it creatingwinds wind
bent by Coriolis Effect approach equator at 45 angle where there is
no land steadiest winds Westerlies at middle latitudes move in
oppositedirection Polar easterlies at high latitudes most variable
winds 16. 3. Surface Currents Winds push the sea surface creating
currents Surface current moves off 45 Top layer pushes on layer
below & again Coriolis Effectcome into play Second layer moves
slightly to right and slower and isrepeated down the water column
(Ekman spiral) lower waters move progressively at greater angles
fromwind effect of wind decrease with depth 100 m no wind is felt
produces Ekman transport upper part of water column moves
perpendicular to winddirection to right N. Hemisphere & left in
S. Hemisphere 17. trade winds move toward equator the
equatorialcurrent move parallel currents combine into huge gyres
west side of gyres carry warm water to higherlatitudes while cold
current flow on eastern sides giant thermostat warming the poles
& cooling tropics tropical organisms like corals tend to extend
into high latitudes on the west sides of the oceans cold loving
organisms like kelp grow closest to equator on eastern shores 18.
large-scale fluctuations can cause conditions like ElNino current
shift with season and weather near the continental shelf currents
are effect by theshape of the bottom & coastline 19. B.
Thermohaline Circulation and the Great Ocean Conveyor Ocean water
stratified Cold more dense on the bottom & warmer less dense on
top1. The Three-layered Ocean Surface layer or mixed layer 100 to
200m thick Mixed by wind, waves and currents Sometimes in summer
& spring in temperate & polar waters sharp transition to
cooler water (theromoclines) noticed by divers Intermediate layer
depth of 1000 to 1500m Main thermocline rarely breaks down & in
open ocean Deep or bottom layers Below 1500 m typically less than
4C 20. 2. Stability and Overturn Water column with less dense water
on top and densewater on bottom with no mixing is stable Depends on
the difference in densities between layers If difference is small
not much energy is needed tomix the water Downwelling occurs when
top layers become moredense & sinks The sinking water displaces
and mixes with deeperwater (overturn) Density & temperature
profiles are straight-lined Temperate and polar during winter 21.
Mixing layers extends greater into water column Important to
productivity In intense downwelling, large volume of water may
leave without mixing Changes in salinity at surfacePrecipitation,
evaporation, freezing, and temp. Once water sunk it does not change
in salinity and temp. (water mass) Oceanographers can follow the
circulation over large distances Because it is driven by density
(determined by temp and salinity) the circulation is called
thermohaline circulation 22. 3. The Great Ocean Conveyer Only
places where surface overturn reaches thebottom is Atlantic south
of Greenland & north ofAntartica The sinking water spreads
though the Atlantic &other ocean basins then eventually rise to
surfaceand flows back Recycles about every 4000 years Regulates
climate and alterations have producedrapid climate changes (ie ice
ages) Bring dissolved oxygen to deep sea 23. 3.3 Waves and TidesA.
Waves Caused by wind Wave crest moves up & forward Trough moves
down and back Water particles do not go anywhere Moves in a circle
Faster the longer the wind the bigger the waves Fetch-span of open
water Larger the fetch the bigger the wave Seas Sharp peaks stretch
over trough Move away get faster than speed of wind 24. Swells Once
waves settle Surf Bottom forces water to move elongated ellipses
Wavelength get shorter Waves pile up becoming higher & steeper
until theyfall forward Water affected by mixture of waves Two crest
adding to make a higher wave (wavereinforcement)As high as ten
stories Trough & crest combine & cancel out the wave 25. B.
Tides Influence marine organisms Organisms are exposed &
submerged on shore Drive circulation of bays and estuaries,
triggerspawning 26. 1. Why Are There Tides? (if watercovered
completely by water) Gravitational pull of sun & moon &
rotation ofEarth, moon, & sun Moons influence gravity strongest
on side of earth closest - pulls water inocean toward it Opposite
side furthest from moon - pull is weakest earths rotation is like
unbalanced tire (wooble) creates acentrifugal force - makes the
oceans bulge out toward the moon & away from moon 2 high tides
and 2 low tides in 24 hours and 50 minutes extra 50 min because for
earth to catch up to moon 27. Sun as strong as moon because so far
away Full & new moon (sun moon in line) Tidal range (difference
between high and low tide) islargeSpring tides First and third
quarter Sun & moon at right angles partially cancel each
otherout tidal range small Neap tides 28. 2. Tides in the Real
World Tides vary depending on location and the shape and depthof
the basin East coast of N. America & most of Europe &
Africa havesemidiur West coast of USA & Canada mixed
semidiurnal tide- successive tides of different height Diurnal ( 1
high and 1 low) rare on Antarctica and parts ofGulf of Mexico,
Caribbean, & Pacific Tide tables give predicted time and height
of high and lowtides Determined by local geology Weather like
strong winds can cause water to pile on theshore creating higher
tide than predictednal tides (2 highsand 2 lows)
