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BioEE 1560 Prelim 1

Terms in this set (113)

Element released by Big Bang
Hydrogen
elements created by nuclear fusion in large stars
carbon, nitrogen, phosphorous
elements created by large stars exploding
gold, nickel, copper, etc.
15 billion years ago
big bang
compressional heating
when temperatures in the core of large masses increase
what forms visible light?
nuclear fusion of H and He
4.6 billion years ago
rock forming elements condensed into grains as nebula cooled, creating planetesimals
4.5 billion years ago
Earth was created
Formation of Earth's moon
mars size asteroid hit earth, knocked off a chunk and created the moon. this is why the earth is tilted at 23.5 degrees
early earth atmosphere
hydrogen and helium
current earth atmosphere
greenhouse effect from water vapor and co2 keeps planet warm, oxygen comes from plants
how did the oceans form?
gradual accumulation of water from comets
How much longer will the sun be around for?
4 billion years
Five major oceans
Atlantic, Pacific, Indian, Arctic, Southern
Body Fossils
lithified bone, leaves direct evidence of organisms
Trace Fossils
includes footprint, marks of movement, etc.
Chemical Fossils
oldest fossils, found in radioactive isotopes like C14
4 billion years ago
origin of first life on earth, oceans only
3 billion years ago
oxygen atmosphere forms from action of photosynthetic bacteria in the ocean
2 billion years ago
first multicellular life on earth, oceans only
550 million years ago
Cambrian explosion, first life on land (plants, animals, bones, vertebrates)
250 million years ago
largest mass extinction, first mammals and first dinosaurs BEGIN
65 million years ago
asteroid impact, dinosaurs wiped out, rise of the mammal
3 methods of measuring ocean bathymetry
1) single beam sonar
2) multi-beam sonar
3)towed multi-beam sonar
single beam sonar
creates a trackline of bottom depth
multi-beam sonar
creates a swath of bottom depth
towed multi-beam sonar
creates a high resolution swath of bottom depth
Alfred Wegner
distribution of fossil and mineral belts provided proof for continental drift
extensional faulting
indication of seafloor spreading
paleomagnetism
strips of alternating magnetic polarity at spreading regions
magnetic anomalies
proxy measure of geologic time; each anomaly is assigned a specific date
significance of deep sea trenches
helped to explain eventual loss of ocean crust
driving mechanisms of plate tectonics
convection in the mantle and slab pull
pangea
supercontinent that existed 225mya and broke apart to form our current continents
Divergent boundary
when two plates pull apart creating a rift zone, new crust is formed here
Convergent boundary
when two plates collide, can result in either subduction (O-C or O-O) or folding (C-C)
Transform boundary
when two plates slide past one another
properties of continental crust
thick, less dense (2.7gm/c^3), older
properties of oceanic crust
thin, dense (3.3 gm/cm^3), generally younger than C crust
example of divergent boundary
East Africa rift zone
example of convergent boundary
indian and eurasian creating himalaya mntns, nazca and south american creating Andes Mntns
mantle hot spot
stationary mantle plume underlying a moving tectonic plate, creates island chains like hawaii
sediment accumulation rate
1-5cm every 1,000 years
terrigenous sediment
river sediment that runs off from land and builds up around the edges of continents
red clays
slow rain of continental dust (very little biological input)
Calcareous or Siliceous sediment
high biological productivity regions with low terrigenous material input
proxy measure of past ocean conditions
remains of plankton contained within sediment cores reveal past surface temperatures and biological productivity
ocean proxy temperatures
measured using isotope ratio of O18 to O16; calcite in shells grown in colder temperatures will have more O18 than calcite in shells grown at warmer temperatures
5 mass extinctions
from first to last: End O, late D, end P (biggest), end Tr, end J, end K (dinosaurs)
sixth mass extinction
currently happening because of humans
What determines wave speed?
wavelength and bottom depth
in exceptional circumstances, how can determinants of wave speed be altered?
In very deep water (deep water waves), wavelength alone determines wave speed
In very shallow water (shallow water waves), variations in bottom depth alone determines wave speed.
Deep water waves
bottom depth is deeper than 1/2 wavelength, longer wavelength waves move faster
shallow water waves
bottom depth is shallower than 1/20 wavelength, all waves in shallower water move slower than they would in deep water
wave dispersion
self sorting of deep water waves
headlands
where wave energy is focused
bays
where wave energy is dispersed
summer beaches
wide, sloping and sandy
winter beaches
rocky, flat after a storm (sand stored in offshore sandbar)
Rip currents
water is funneled through narrow breaks in underwater sand bars to form very narrow, accelerated jets of water
Wave height is a function of...
1) wind speed
2) duration
3) fetch
wind speed (for waves)
sets the upper possible limit of wave height
duration of wind (for waves)
modulates the upper possible limit
fetch
the distance over which wind can blow unobstructed, modulates upper possible limit
effect of larger fetch
gives the storm more time to pump up the size of a given wave before the wave propagates out from under the storm center
Tsunami
generated at convergent plate boundary from sudden release of seismic energy
equilibrium model of tides
highly idealized but very instructive view of tides
daily tidal patterns
diurnal, semidiurnal and mixed semidiurnal
diurnal
one high tide and one low tide a day
semi-diurnal
two equal high tides and two equal low tides per day
mixed semidiurnal
two unequal high tides and two unequal low tides per day
tidal bulge
caused by pull of moon's gravity and centrifugal force
Spring tides
occur when the moon pulls along the same line as the sun (new and full moon) , most exaggerated tides
Neap Tides
occur when the moon pulls at 90o to the sun (first and last quarter moon), least exaggerated tides
why do we get tides in the ocean and not in lakes?
ocean is pinched upward from the cumulative lateral pull by the moon on all the ocean; lakes are not large enough for this broad lateral pinch
rotary motion of a tide wave
caused by coriolis force directing the movement to the right in northern hemisphere and to the left in southern hemisphere
Amphidromic point
very little (almost no) tide near this point; it's the center of a rotary tide
co-tidal lines
measure hours in a rotary tide diagram
co-range lines
measures meters spread out from the amphidromic point
Tidal ranges depending on location
coastal regions generally exhibit the largest tidal ranges
tidal ranges can be exaggerated by:
1) Forcing ocean water into a narrow embayment
2) Tidal forcing that is in resonance with the tide wave
global surface wind patterns
1. Three primary wind belts
2. Contained within latitude bands
0-30, 30-60, 60-90
3. Wind belts alternate direction
trade winds
between 0-30 in latitude, converge in on the ITCZ
westerlies
between 30-60 degrees, move outwards
easterlies
between 60-90 degrees, converge in on the poles
Coriolis in the Northern Hemisphere
directed to the RIGHT
Coriolis in the Southern Hemisphere
directed to the LEFT
The Basic Rule of Coriolis
1) point your nose in the direction of the ocean current (or wind) is moving
2) stick your hand directly out from your side
short wavelength radiation
visible light, passes right through the atmosphere without being absorbed and, consequently, without much direct heating of the atmosphere from the sun
long wavelength radiation
this energy is absorbed by the atmosphere and, consequently warms the atmosphere.
greenhouse effect
atmosphere is heated from below by re-radiating energy that is reflected off of earths surface and then trapped by the atmosphere
effect of direct solar heating at equator
atmospheric convection and precipitation is strongest along the equator
hadley cell
The atmospheric circulation cell nearest the equator in each hemisphere. Air in these cells rises near the equator because of strong solar heating there and falls because of cooling at about 30° latitude
solar heating of water
direct solar heating takes place very near the ocean surface (0-30 meters).
water below 500m
uniformly cold; does not get mixed
permanent thermocline
broad region centered at around 500 meters where seawater temperature changes from warm to uniformly cold
seasonal thermocline
shallower thermocline that only forms in summer and is then is erased in winter
seasonal pycnocline
region of strong change in density with depth, comes and goes with net heat gains in spring and summer and net heat losses in fall and winter
permanent pycnocline
remains in place (at around 500 meters) and is the result of the long-term balance between the downward heating/mixing at the surface and upward mixing of cold water from below
Ekman Transport
due to Wind Force, Friction Force and Coriolis Force, ites the rate of total water transported in the Ekman Layer (a layer that is about 50 to 100 meters thick)and is exactly at 90 degrees from the wind direction
Eckman Layer
slab of water that moves in unison at 90 degrees to the right (northern hemisphere) or left (southern hemisphere) of the wind
geostrophic balance
point at which currents move with steady speed with Coriolis and pressure gradient forces in perfect opposition
geostrophic current
current that results from geostrophic balance
development of subtropical gyre
Westerly and Trade Winds drive the Ekman Layer to the center of the gyre to create a mound of surface water, the push of Coriolis turns the fluid until it travels along concentric lines of constant pressure
western boundary currents
very swift and narrow jets that bring warm water from the tropics to high latitudes
eastern boundary currents
broad and slow and bring cold water from the high latitudes toward the tropics.
equatorial upwelling
Water is drawn up from the base to the shallow surface Ekman Depth. If the thermocline is close the Ekman Depth, then cold water is drawn to the surface and if the thermocline is deep only more warm water is drawn the the surface
Eastern Equatorial Pacific Cold Tongue
due to equatorial upwelling AND the close proximity of the thermocline to surface Ekman Depth
Western Equatorial Pacific Warm Pool
upwelling still occurs, but the thermocline is much deeper than the surface Ekman Depth so upwelling just draws more warm water to the surface
Temperature-Salinity "Signatures"
1. NADW: North Atlantic Deep Water (34.8 ppm)
2. AABW: Antarctic Bottom Water (34.6 ppm)
3. AAIW: Antarctic Intermediate Water (34.2 ppm)
Deep ocean circulation
Cold dense water sinks in the North Atlantic and around Antarctica to form deep water--> North Pacific salinity is too low to sink even though temperatures are just as cold as the North Atlantic -->Deep water in the North Atlantic moves south and mergers with Antarctic water in the Southern Ocean as they both swing around Antarctica and up into the Indian and Pacific Ocean basin
how long does water take to circulate?
2,000 years
how is heat transported to high latitudes in the ocean?
through strong Western Boundary Currents
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