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Case History: UFOs
Featured Organism p. 9, 22: Maldive
coconut (coco de mer)
Featured Organism p. 22, 28: ocean
sunfish or links 1
- 2 - 3
- 4
I. Ocean Gyres and Currents
terms:
gyres
a) Surface Currents
terms:
Antarctic Circumpolar Current (West Wind Drift),
East Wind Drift, Equatorial Countercurrent, North/South
Equatorial Currents
RQ2.1:
Describe the primary global currents, starting with the
most important ones
b) The Winds That Drive the Currents
terms:
northeast/southeast trade winds (trades), westerlies,
polar easterlies, meteorological equator, doldrums,
horse latitudes, southwest/northeast monsoon
RQ2.2:
If trade winds blow westward, why does the Equatorial
countercurrent travel eastward?
c) The Effects of Surface Currents
on Marine Communities
terms:
polar/cold-temperate/warm-temperate (subtropical)/tropical
1) Currents
compress or expand communities
along continental shores
Featured Organisms p. 26:
Cancer amphioetus
(warm-temperate crab,
nice images with Japanese text)
Arctica islandica (cold-temperate
clam,
better know as ocean quahog)
RQ2.3:
Why does the warm-temperate crab have a narrower
latitudinal distribution (north to south) on our West
Coast than it does in the vicinity of Japan?
2) Currents carry
organisms to hostile environments
terms:
rings, warm-core ring, cold-core ring, expatriate organisms
Featured Organisms p. 28:
California (or Pacific)
baracuda or links 1
- 2
blue
shark or links 1
- 2
albacore or links
1
- 2
black durgon
(triggerfish) or movie 1
RQ2.4:
If so-called "expatriate" organisms can occasionally be
transported far north or south of their normal range, why
do they tend to disappear after a few years?
II. The Movements of Deep Ocean Waters
a) The Density of water
terms:
density
(mass divided by volume)
1) Water of
low density floats; water of high density sinks
terms:
stratified vs. unstratified water
RQ2.5:
Why does the ocean become stratified and what
time of year does it become this way. Why and when
does it become unstratified?
2) Cooling,
freezing, and salt concentrations cause surface
seawater to sink
terms:
turnover, profiles, thermocline
b) The Strata of Water in the Oceans
terms:
surface layer, upper/intermediate/deep/bottom waters
1) Surface waters
form everywhere; Central and Equatorial
waters form in the subtropics
terms:
Equatorial Water, Central Water, Subtropical Convergences
2) Sinking
water forms the deepest three layers
terms:
Antarctic Bottom Water (ABW), North Atlantic Deep Water
(NADW), Antarctic Divergence, Antarctic Convergence, Antarctic
Intermediate Water (AIW)
RQ2.6:
Imagine you are in a submarine in the middle of the
Atlantic Ocean on the Equator. Describe the discrete layers
of seawater of different densities and temperature that you
expect to pass through on your way to the bottom. Where
did each layer originate? (Challenge question: When was
it last at the surface?)
3) Sinking surface
water carries oxygen to the deep sea
bottom
terms:
thermohaline circulation
RQ2.7:
You finally made it to the bottom (see last question) and
find some deep sea organisms living there that depend on
oxygen for their normal respiration. What is the source of
that oxygen?
4) The Cariaco
Basin has no deep flows and therefore
no oxygen, no animals
terms:
anaerobic bacteria, toxic hydrogen sulfide, anoxic water
5) Some fishes
avoid the East Pacific oxygen minimum
terms:
oxygen minimum
c) Deep-Water Avenues to Other Oceans
terms:
submergence
RQ2.8:
Why don't the Pacific and Indian Oceans have
circulation patterns from the polar regions that
were described for the Atlantic Ocean?
III. Upwelling
terms:
upwelling
a) Coastal
Upwelling
terms:
Coriolis
effect, downwelling
Having trouble visualizing it? Check out this animated Coriolis effect
The truth behind the Coriolis effect
and whether it affects toilet bowls
and sinks: 1
- 2
- 3
RQ2.8:
When does coastal upwelling affect the California coast
and what consequences does it have when it does?
RQ2.9:
Why do many coastal marine animals that have a
planktonic larval stage seem to have especially good success
at settling out of the plankton onto the shore during years
when there is not much coastal upwelling?
b) Equatorial Upwelling and the Great Antarctic
Divergence
terms:
Antarctic Divergence
RQ2.10:
How is the upwelling that occurs around the Antarctic
continent fundamentally different than coastal upwelling
elsewhere in the world?
IV. Estuarine Circulation
terms:
estuary, estuarine circulation, salt wedge, negative
estuary, positive estuary
V. Tides
terms:
tides
a) The Effect of the Moon,
the Sun, and
the Shapes of Ocean Basins
terms:
tidal
bulge, high tide, low tide, mixed tide (as in California),
semidiurnal tide, diurnal tide (see Fig. 2.19), MLW, MLLW,
zero tide level, spring
vs. neap tides, MSL
Visit
the source of this animated image here
or
click here
for a similar but more detailed animation
Tides stumped Galileo
and others.
Newton finally figured out why they occur.
RQ2.11: Why are there two low tides most days in California?
RQ2.12:
Why does the lowest of the two low tides each day
occur about 50 minutes later than the day before?
RQ2.13:
Why are the low tides lower than average about every
two weeks (at the full
and new moons)?
The Moon
is mostly responsible for tides, but the shape of ocean
basins can
make a very large difference.
Tides
can be extreme in some areas, like the Bay
of Fundy, while other
places like
the Adriatic Sea have relatively little tidal fluctuations.
Unusually severe
tides can sometimes wreak havoc if unchecked,
as those who
live in London
know.
b) Critical Tide Heights on Intertidal
Shores
terms:
critical tide levels, tidal zones
RQ2.14:
In Seattle (Fig. 2.19), animals living at +8 ft. tidal
height will be uncovered by low tides twice each day,
while animals lower on the shore at +4 ft. only get
uncovered once each day. How come?
VI. Waves
terms:
wave,
wavelength, wave height, crest, trough, surge,
exposed vs. protected shore
RQ2.15:
What makes a wave break as it approaches the shore?
Why are some areas more impacted by waves than others?
VII. How Organisms Use Currents and Tides
terms:
life cycle closure
Featured Organism (p. 46, Fig. 2.25):
Velella velella
(By-the-wind Sailor) or links 1
- 2 - 3
a) Adaptation to Tidal
Rhythms
terms:
endogenous rhythm
Featured Organisms
p. 48: California
grunion or links 1
- 2
Expected grunion runs March
- August 2002
p. 49: fiddler
crab or links 1
- 2 - 3
- 4
RQ2.16:
What advantage does a California grunion have
if it is synchronous with the activities of other grunions?
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Chapter
3
This page created 2/3/01 © D.J. Eernisse, Last Modified 2/12/02, Last Completely Checked 2/12/02