Lecture
Notes 1—
A Unique Planet Life would not be
possible without large amounts of water.
Water has the ability to retain heat, moderate temperature, dissolve
many chemicals, and suspend nutrients and wastes. A Unique
Planet All life, from a jellyfish to a dusty desert
weed, depends on saline water within its cells to dissolve and transport
chemicals..indicating that simple,
self-replicating-living molecules arose somewhere in the early ocean. A Unique
Planet How long ago…probably at least 3.4-3.5 billion years
ago as the oldest fossils yet found indicate.
The most
striking and distinctive feature of our planet, when viewed from space, is the
amount of water on its surface. Its called the water
planet. And, while some is contained in clouds as water vapor and a few percent
is present in lakes, rivers ice caps and in cavities of pores of rocks, most is
contained within the oceans. The sea probably played a part in man's life and
experience from the very earliest times, even his prehuman ancestors are likely to have included shellfish
from the shore in their diet.
Water transportation was used at least since 50000 years ago
to colonize Australia and maybe even longer but little trace remains because of
the materials used for primitive boat building, reeds, wood, skins rapidly
decompose. While the Greeks, Pacific Islanders and Vikings were responsible for
some of the earlier spectacular maritime achievements, the Portuguese sea men
were the first true pioneers of European oceanic exploration. Sent out by
Prince Henry in 1420's they continued new discoveries, and charted these with
considerable skill. In the 1460's they devised a system of nautical astronomy
to improve navigation.
The map shows the world known to Homer at about that time, and
shows that knowledge of the seas was centered in the Aegean, and extended
generally throughout the eastern Mediterranean. The Greeks of that time
imagined the world to be a large disk with upturned edges, with the center of
the disk in the Aegean, surrounded by a river.
Although the
Phoenicians had traveled into the Atlantic centuries earlier, the Greeks were
probably unfamiliar with the Atlantic Ocean, or any seas beyond the
Mediterranean. Between the eighth and sixth centuries BC, Greeks of the
historic period began voyaging more extensively beyond the Aegean, although not
venturing out of the Mediterranean until the fourth century BC..
Renewed
interest in natural history began to increase by the 16th century,
and over the next few hundred years there were many studies carried out by what
we would today call amateur naturalists.
These were usually professional men in other fields, often
physicians or explorers, but generally were individuals not specifically
employed to carry out natural history studies.
Notable among these
are the explorations of Humboldt and of James Cook, who made extensive voyages
and observations of the natural world.
One of the
early professional naturalists that made significant contributions to marine
biology was Charles Darwin. Darwin, most famous for his later works on theories
of evolution, was commissioned early in life as a naturalist on the
The British
ship HMS Challenger investigated the oceans worldwide between
1872-1876, finding a large number of new species. Sir Charles Wyville Thomson (Professor of Natural History at the
University of Edinburgh, and director of the civilian scientific staff on the
Challenger) published the findings of the Challenger expedition in a series
known as the Challenger Reports.
Until the
middle of last century, marine biologists relied primarily on nets, grabs, and
dredges to collect samples in almost every marine habitat except the intertidal
zone, where collections could also be made by hand and organisms could be
directly observed. As an example of the ships and techniques, the U.S.S.
Albatross of the United States Fish Commission carried out a number of
expeditions from 1887 to 1925. Some of the equipment used on the Albatross are
pictured below
In 1934,
zoologists William Beebe and Otis Barton were the first to observe relatively
deep sea habitats directly aboard the "bathysphere", which remained
tethered to a surface ship during the entire dive.
They reached a depth of
923 meters (3,072 feet). The advent of modern Self Contained
Underwater Breathing Apparatus (SCUBA), underwater photography, and manned
submersibles have allowed us to see firsthand much of the marine
environment that we previously could not observe. The
development of a wide variety of electronic measuring devices and instruments,
unmanned submersibles, and remote sensing by
satellites
and aircraft has also greatly increased our ability to measure and study parts
of the marine environment that are difficult to observe in person.
Even so, because of logistical problems associated with
conducting research in much of the marine environment, our knowledge of
conditions in most of the seas and oceans lags behind our knowledge of the
terrestrial environment.
By
the 1480's a pilot could calculate his latitude. Longititude
could not be measured yet so "running down the latitude" was
practiced...sailing to the latitude of landfall, for three to four hundred
miles seaward and then sailing due east or west to the landfall. Columbus used
his method on his return voyage from the New World.
It wasn't until 1760+
that John Harrison's fourth chronometer and the lunar distance method of
calculating longitude provide answers to measure longititude
at sea. Latitude and Longitude 1st and 4th Chronometer by John
Harrison
Albatross In August
1882, the United States Commission of Fish and Fisheries launched the first
vessel built especially for marine research by any government—the steamer Albatross.
Perhaps even more impressive than being the first government vessel equipped
throughout with electric lights, Albatross has been credited with
discovering more new marine species than any other research vessel.
The American
Navy's' ship the Blake carried out research from 1877-80 in the Caribbean gulf
of Mexico and coast of Florida and from there the science continued to
flourish... Note names!
Pathfinder
was the first survey ship to have a nautical chart printing press installed
onboard. During World War II, the vessel churned out thousands of charts for
fleet units. Captain Junius Jarman
of the C&GS was instrumental in developing techniques for chart printing in
a shipboard environment. Latitude and Longitude Longitude
On
the globe, lines of constant longitude ("meridians") extend from pole to pole, like the segment
boundaries on a peeled orange
Latitude and Longitude Every meridian must cross the equator.
Since the equator is a circle, we can divide
it--like any circle--into 360 degrees, and the longitude of a point is then the marke
d value of that division where its
meridian meets the equator.
Latitude and Longitude Any location on Earth is described by two
numbers--its latitude and its longitude.
If a pilot or a ship's
captain wants to specify position on a map, these are the
"coordinates" they would use.
Latitude and Longitude On a globe of the Earth, lines of latitude
are circles of different size.
The longest is the equator, whose latitude is zero, while at the poles--at latitudes
90° north and 90° south (or -90°)
the circles shrink to a point.
Did you know that you can use the stars to tell directions at night? The
North Star, or Polaris, is usually within 1-2 degrees east or west of true
north. Polaris is at the top of the handle of the Little Dipper, a
constellation that is easy to find in the Northern Hemisphere.
You can also use the North Star to determine latitude in the Northern
Hemisphere. Use an astrolabe, used to determine the altitude of objects
above the horizon, to find your latitude. You can make your own simple
astrolabe using a protractor, plastic straw, 12-inch piece of string, and a
metal weight (a small bolt or a washer works well). Tie one end of the string
to the hole in the middle of your protractor. (If there is not a hole, drill
one in the center of the flat-edged piece on the protractor.)
Latitude and Longitude 1st and 4th Chronometer by John
Harrison Latitude
and Longitude What that value is depends of course on
where we begin to count--on where zero
longitude is.
For historical reasons, the meridian passing
the old Royal Astronomical Observatory in Greenwich, England, is the one chosen
as zero longitude. Latitude
and Longitude Old Royal Astronomical Observatory in
Greenwich, England, Latitude
and Longitude Located at the eastern edge of London,
the British capital, the observatory is now a public museum and a brass band
stretching across its yard marks the "prime meridian.“ Tourists often get photographed as they
straddle it--one foot in the eastern hemisphere of the Earth, the other in the
western hemisphere. Latitude
and Longitude A lines of longitude is also called a meridian, derived from the Latin, from meri, a variation of "medius" which denotes "middle", and diem, meaning "day." The word once meant "noon", and
times of the day before noon were known as "ante meridian", while
times after it were "post meridian."
Today's abbreviations a.m. and p.m. come
from these terms, and the Sun at noon was said to be "passing
meridian". Latitude
and Longitude All points on the same line of longitude
experienced noon (and any other hour) at the same time and were therefore said
to be on the same "meridian line", which became "meridian"
for short.
Latitude and Longitude Time Zones
On the Mississippi river in the 1850s, the leadsmen also used
old-fashioned words for some of the numbers; for example instead of
"two" they would say "twain". Thus when there was only two
fathoms left under the boat they would call "by the mark twain!". The American writer Mark Twain, a former river
pilot, likely took his pen name from this cry.
Sonar
How does Sonar work? Sonar
is a device that is used to detect objects through sound waves.
There are two main types of sonar: Active and Passive. Sonar
technology enters a signal into the water in a narrow beam which has the speed
of about 1500 m/s.
Sonar Ocean Floor
Contour using Sonar Sonar If
there is an object in the beam, its sends sound energy back to the sonar dish. Then the distance is calculated by range =
sound speed x travel time / 2. In active sonar a pulse signal is sent to a
transducer which changes the electrical signal into a sound signal.
Sonar After that it is put out into the water and it
detects returning echos. A
receiver amplifies the soft echos and measures the
range of each object.
Sonar Old Method
Sonar New Method up to 121 beams.
Sonar Geosat from
Orbit! Sonar Geosat Image
Radar Radar works
by sending out a radio wave at a very high frequency.
When the radio signal hits raindrops part of
the signal bounces back to the radar.
The signal travels at the speed of light (over 350,000 kilometers per
second!).
Radar Knowing exactly how fast the signal is travelling, means
that we can tell how far away the rain is by timing how long it takes for the
signal to travel to the rain and then bounce back to the radar. This happens so fast that most radars send out about 1000 signals (called pulses) each
second!!
Loran A long-range radio navigation position fixing system
using the time difference of reception of pulse type transmissions from two or
more fixed stations.
This term is derived from the words long-range
electronic navigation.
All radionavigation systems, including GPS, have their
weaknesses. On February 7, 2008, the U.S. Department of Homeland Security (DHS)
announced that it would begin implementing Enhanced Loran (eLoran),
an enhanced and modernized version of Loran-C, as the U.S. national backup
system. This independent, positioning, navigation, timing, and data delivery
system would mitigate the safety, security, or economic effects of a loss of
GPS for critical infrastructure applications, especially those that require
precise time and frequency. GPS GPS system of
satellites--the Global Positioning System. That network of 24 satellites
constantly broadcasts its positions, and small hand-held receivers exist which
convert those signals into positions accurate within 15 meters or about 50
feet.
GPS
In circular orbits at distances of
about 4.1 Earth radii (26,000 km or 16,000 miles), GPS satellites
continually broadcast their precise locations, and these can be read by small
portable receivers, relatively inexpensive.
GPS
Using a built-in computer, these
receivers then derive their own precise position on the ground, within 10-50
meters. .
Russia operates its own system, GLONASS, and
European countries are planning a third on GLONASS constellation status, 13.01.2009г. Total satellites in constellation 20 SC Operational 16 SC In
commissioning phase 3 SC In maintenance 1 SC In decommissioning phase -
e. GPS Originally developed by
the US Department of Defense (whose users derive from them even more precise
positions), the GPS satellites are widely used by the public--by ships at sea,
airplanes, hikers in the wilderness, even drivers trying to navigate large cities
By means of
four or more satellites, an absolute position in a three dimensional space can
be determined. A 3D-position fix also gives the height above the earth surface
as a result.
By constantly recalculating its
position, the GPS receiver can additionally determine the speed and direction
of a movement (referred to as "ground speed" and "ground
track").
Introduction
To the Oceans About 71% of the surface of the planet is
covered in salt water. Beneath the
depth averages 3,8 km giving it a volume of 1370 x 106
km3. Since life exists throughout this
immense volume, the oceans constitute the single largest repository of
organisms on the planet. Introduction
To the Oceans These organisms include representatives of all
phylums and are tremendously varied but all are
subject to the properties of the sea water that surrounds them. Many
features common to these plants and animals are the results of adaptations to
the watery medium and its movements. Introduction
To the Oceans Its necessary therefore, to examine the
physical and chemical conditions of seawater and aspects of its motion
(oceanography) and look at the environment where the organisms live.
Introduction
To the Oceans Hydrologic (Water) Cycle Introduction
To the Oceans Where is all the Water? Introduction
To the Oceans Ocean Basins
Introduction To the Oceans Ocean Basins Introduction
To the Oceans The mean depth is 4km (2.5 miles)and its
interconnected from the Arctic to Antarctic. Seawater flows freely among the basins
transporting dissolved materials, heat and marine organisms. Seawater mixes from basin to basin/per 1000
years but regional characteristics of the seawater do exist. Introduction
To the Oceans The major basins are the Pacific, Atlantic,
Indian, Arctic, Southern ocean and the boundaries are artificially defined.
Introduction
To the Oceans Seawater mix
Movement of water moderates world climate by distributing heat from
equatorial water to the poles. Warm
currents flow toward the poles from the equator (Gulf Stream) heating northern
latitudes. Cold water from the Arctic
and Antarctic basins flow beneath the oceans surface toward the
tropics...cooler water near the equator. Introduction
To the Oceans SEA LEVEL
The sea level has undergone dramatic changes. 15000 years ago 120m below
present level. As it fell portions of
the continental shelf were exposed changing position of coastline. Ice age/Wisconsin glacial period, the ocean
water froze into glaciers. Introduction
To the Oceans SEA LEVEL
Introduction
To the Oceans It is still rising. The rise slowed 3000 years ago and has only
risen 10m since. CO2 is warming the Earth and the ice could
melt and flood low lying areas in the next 1000 years.. Green
House effect.
Introduction
To the Oceans The Ocean Floor Prior to the 1920's, they used weighted rope
to probe depths. 1920's the echo
sounder (SONAR-(sound navigation and ranging) which analyzed sound waves which
bounced off the oceans bottom and returned to the ship. The Meteror (1925-7)
did the 1st ocean survey with sonar.
Introduction
To the Oceans Common topographical features of the oceans
include: Continental margin and deep sea as the major divisions. Continental Margin Continental
shelf-underwater extension of the continental land mass.
8% of
the total surface area of the world ocean, yet its one of the most productive
parts of the ocean.
It gradually drops down
to the 100-200m depth. Introduction
To the Oceans Formation of Continental Shelf
Introduction
To the Oceans Continental slope begins where continental shelf
plunges down.
As the steepness decreases, this zone is
called the continental rise. Introduction
To the Oceans Locations of Continental Shelfs Introduction
To the Oceans Soft sediment of the shelf exposed to
erosion from rivers and then the glaciers started to melt, excess water cut
canyons into the shelf.
Ocean refilled,
flooding shelf and forming underwater canyons.
The rise slowed 3000 years ago and has only
risen 10m since.
Introduction
To the Oceans Underwater canyons occur in the margins which
resulted from when the ocean level was
lower with rivers flowing over them eroding the soft sediments making deep
gouges. Underwater landslides along the sides of the
canyons make the canyon bigger Introduction
To the Oceans
Introduction
To the Oceans Types of Reefs
Fringing-along the land Barrier-a
lagoon between the land and reef Atoll-a
reef around a lagoon (formally an island since eroded. Introduction
To the Oceans Types of Reefs
Introduction To the Oceans
Trench Formation Converge: one plate dives under another,
crumples and forms trenches...
Introduction
To the Oceans T
urbidity Currents Avalanche-like
sediment movements caused when turbulence mixes sediments into water above a
sloping bottom. Since this
sediment-filled water is now denser than the surrounding water, thick, muddy
water can run down the slope
at speeds up to 17mph. These
currents may have been responsible for enlarging submarine canyons Introduction
To the Oceans Turbidity Currents
PLATE TECTONICS There are 8 major plates, up to 100 miles
thick and move slowly.
They know the direction
and speed so can figure out what the continent was like before it moved.
The Atlantic has been
growing for 150 mil years. The theory of
continental drift or plate tectonics was only established in the 1960's. 200 million years ago, Pangaea fractured and
started moving apart 180 mil. yrs
ago.
Plates
PLATE TECTONICS ALFRED WEGENER
(1880-1930) German climatologist and geophysicist who, in 1915, published as
expanded version of his 1912 book The
Origin of Continents and Oceans. This work was one of the first to
suggest continental drift and plate tectonics.
PLATE TECTONICS He suggested that a supercontinent he
called Pangaea had existed in the past, broke up starting 200 million
years ago, and that the pieces ``drifted'' to their present positions. He cited
the fit of South America and Africa, ancient climate similarities, fossil
evidence (such as the fern Glossopteris and mesosaurus),
and similarity of rock structures. PLATE TECTONICS
The force that moves the plates over
the semi-solid layer of the upper mantle /asthenosphere
is the convection currents
(large temp. difference between the mantle and crust) and moves
plates either 1. apart, 2. together or 3. laterally. Surtsey, Iceland;63.30 N 20.62 W;170 m elevation
This photo, taken on November 30, 1963, shows the sixteen-day-old cone which
became the Island of Surtsey, off the southern coast
of Iceland. Born from the sea, it has provided scientists a laboratory to
observe how plants and animals establish themselves in new territory. The
eruption began 130 m below sea level, where it proceeded quietly until the
height of the volcano approached the sea surface. Then the explosive activity
could no longer be quenched by the sea. A black column of volcanic ash announced
the island's birth on November 14, 1963. Jets of dense black ash shot skyward
and the towering eruption cloud rose to a height of 9 km. By April of 1965, ash
had blocked sea water from the crater area. Lava flows became prominent,
forming a hard cap of solid rocks over the lower slopes of Surtsey.
This prevented the waves from washing away the island. The three and one-half
year eruption was over in June 1967. Photo credit: Howell Williams PLATE TECTONICS
1. apart new material rise as magna /molten
rock filling spaces (rifts form mid ocean ridge. evidence 1965
research vessel Eltanin did magnetic studies
1969 Glomar Challenger did cores from
Pacific-Antarctic ridge
1977 Project Famous used submersibles
PLATE TECTONICS
2.
Converge one plate dives under
another, crumples and forms trenches...usually but not always (mountains) the
area is called a subduction zone Island arcs formed/volcanos/
from turbulence from the melting of the descending plate. PLATE
TECTONICS
3.
Lateral-sideswipe and cause earthquakes volcanoes and deformations
PLATE TECTONICS
Hydrothermal
vents...water percolates into fissures around the rift valley, sinks and heats
to 320'C in fissures (pressure). The heated water dissolves metals and it rises
to the seafloor surface,openings flow through the
hydrothermal vents, mix with cold water, minerals settle to bottom forming
deposits. Robert Ballard witnessed milky
bluish clouds spewing in a Pacific rift zone.
Global Hotspots
Pacific
Plate Motion Moves
W/NW at approx. 5-10 cm per year
Currently being subducted beneath the N. American and Eurasian plates
(Aleutian Trench)
Moves over stationary
hot spot in Earth’s mantle Hot
Spot Theory 1963-
Proposed by J. Tuzo Wilson Evidence:
Oldest Volcanic rocks of Kauai (most NW island) are dated at 5.5 million
years old and greatly eroded.
Oldest rocks of the Big Island are approx. 0.7 million years
old.
Hot Spot:
magma from within the Earth’s mantle pushes up the Earth’s crust resulting in
the formation of an undersea volcano.
The Next
Generation: Loihi Located off the
Southwest coast of Hawaii Currently,
6000 ft above the sea floor (about 1km from the surface) Predicted to
poke through surface in about 1 million years. So, don’t make vacation plans
just yet! Caribbean
Tectonics Puerto
Rican
Tectonics and Seismic Hazard
Puerto Rican
Tectonics and Seismic Hazard
. Seawater
Chemistry
1.Q. Does the saltiness
of seawater vary? Q. What makes
seawater salty? 2.Q. Where does the salt come
from? Q. Is the ocean getting
saltier? 3.Q. Do the components of
seawater all behave similarly? 4.Q. How
variable is the composition of salts in seawater? 5.Q. Which gases are dissolved in seawater? 6.Q. What role do the gases play in sustaining life in the
ocean? 7.Q. Can the salt be removed
from seawater?
Water Chemistry Information
Pressure Air is .1% as dense as water and the ocean
pressure is directly proportional to its depth and acts in all directions
within the water 6/3/2002 Pressure
The atmospheric pressure is 1kg/cm2 (14.7lbs/sq in)= 1 ATM. An increase
of 1 atm for each 33' or 10m and at 30m (100') the
pressure is 4atm (1atm/10m + 1atm for air). Mariana trench 11,034m (36192')= 1000atm.
Pressure This is
known as hydrostatic pressure and because of it, many organisms restricted to
particular level or depth and those that can go to all areas have evolved
adaptations to compensate for the change.
Density
Salt water is 800x
greater in density than air (supports big organisms). The
density is affected by temperature. As water cools, Density
1. water molecules
move closer, increasing density..
2. 4'C max density (1g/cm3)
3. cooler
decreases density..ice= .92g/cm3 and is less dense so
it floats.
Temperature: Water has
a high heat capacity...ability to resist rapid temperature changes and is
transferred by convection. Temperature: Temperature is the most important physical
factor in the marine environment limiting the distribution of ocean life by
effecting density, salinity, gas concentration in oceans.
Temperature: There is
minimum vertical mixing because warm water (on top) can't replace cold water. The thermocline is
a narrow zone between warm surface water and cold bottom water. Temperature effects ectotherms and endotherms.
Temperature 2 It also affects the density as does
salinity so both salinity and temperature must be considered to work out
density, salinity and oxygen level.
Variation of -2 (28) to +30 (86).
Temperature 2 Satellites are now used to monitor water
temperatures
Agulhas Current Gases
Gases enter the ocean by diffusion
from the atmosphere until it reaches saturation level...different for each gas.
Oxygen
O2 makes up 21% of the
atmosphere but in the coldest oceans its less than 1%
to as much as 9%.
Oxygen O2 comes from photosynthesis in the
ocean and this diffuses into the air because water can only hold small amounts
of O2.
The ocean provides 50%
of atmosphere O2. Gases
The most important are O, CO2 and N. Dissolved O2 = aerobic (use O2) and none=
anaerobic... used for respiration and
corrosion. Oxygen Turbulence increases the amount of O2
that can dissolve in water. Dissolved O2
declines rapidly as depth increases...why?? Zones At the depth where photosynthesis=rate
of respiration its the compensation depth.
At the surface as
O2 is used, its replaced quickly by photosynthesis and
as it deepens, respiration becomes greater than photosynthesis.
Light Used for photosynthesis by plants with
chlorophyll. Much is reflected back to
atmosphere and as wave action increases, more is reflected. Light Lots are absorbed by water but 65% of
all light is absorbed within the 1st meter and only 1% gets to 100m. Light Absorption Certain wave lengths are absorbed..blue goes far down and this is vital to photosynthesis as
most autotrophs use red and blue light.
Zones
The sunlit area is the photic
zone where 70% of worlds photosynthesis.
Lower area (not sunlit) is the aphotic
zone =90% of the ocean Photic
zone ranges from 1m in estuaries to 100m in open ocean and depends on
turbidity.
Turbidity increases along the coast as suspended solids
increase.
This causes a shift of
balance because where blue is the predominant absorbed light in crystal clear
water, suspended solids enable wavelengths of green to penetrate deeper than
blue in coastal waters. The highly
productive water of the coast is greenish and estuaries are brownish. The compensation depth is shallower in
coastal waters and below this the autotrophs can't
get enough light for photosynthesis to meet the energy requirements.
Salinity Salinity
is expressed as concentration of ions in a liter of water or # of grams of
dissolved solids in 1000g of seawater. Solvent Water is a
solvent for most substances especially salts.
The characteristics of seawater
are due to the nature of pure water and the materials dissolved in it. Solvent
The solids in seawater come from two
sources, the chemical weathering of rocks washed to the sea by the rivers and
the earth's interior through hydrothermal vents.
Seawater Composition
Water...the wonderful stuff held
together by hydrogen bonds which causes ice to melt at 0 instead of -90.
It causes the absorption of lots of heat to melt ice and same
to evaporate water...cooling.
Seawater Composition
It allows water to hold heat...heat
capacity and the amount of heat needed to change water temperatures help for
cooling of the earth Components
of Sea Water Major components of
seawater vary slightly.
Two processes add salts to the ocean--river
discharge and water circulations through hydrothermal vents (hotsprings). Components
of Sea Water All
ocean water cycles through these vents every 8-12 million years. These work together making seawater, with the
springs adding and removing chemicals.
Salinity Seawater 1000g samples have 34.7g of dissolved
matter so salinity is expressed as 34.7 ppt (0/000)
or 3.47 % . The remaining 96.5% is pure water.
Salinity Today
they can measure electrical conductivity in conjunction with temperature of
water sample.. conductivity
is proportional to salinity
Salinity Also
even though organisms may be exposed to changes in salinity...rivers rain etc,
they don't have to deal with changes in ratios of the various ions dissolved in
the seawater..
Salinity Although
constant, the concentration can change with addition or removal of water. Different in local areas depending on rate of
evaporation/precipitation and volume of fresh water dumped. Salinity
[red sea=40, Mediterranean=38 lack of rain
fall and high evaporation. Black Sea=18 Baltic Sea=8..low
evaporation and high runoff.]
Salinity Body of Water Grams (per
Liter) Ounces(per Quart) Distilled 0 0 Baltic
Sea 7.1 0.2 Black Sea 18.2
0.6 The Oceans 35.4 1.2 Red Sea 40.5 1.4
Great Salt Lake 172 5.7 The Dead Sea 293 9.8 More
Terms Euryhaline=organism
can tolerate large salinities and fluctuation.
Stenohaline can't tolerate large salinity
changes. Vertical change surface layer
mixed..uniform beneath the halocine
layer … large salinity changes above..The salinity changes with depth. Link to aquariums
Review
Questions Online
Review
Answers for 1st Review
Review
Even Answers
Mar sci
ocean floor/tect/chem. Notes EVEN Ans.
2.
Remotely-Operated Vehicles (ROVs) used for deep-sea work have the advantage of
being _safer than are people-carrying vehicles.
4. A flat-topped seamount is called a: guyot
6If the ocean evaporated, Earth's most obvious feature would be:mid-ocean ridge
.8 The deepest places on Earth are: trench
10Transform faults are fractures along which lithospheric plates move: transversely—side to side
12Ice is_less--dense than water
14In addition to mixing in from the air, oxygen enters seawater:
Photosynthesis
16The average salinity of the world's oceans is about (%o = parts
per thousand) 35ppt
18. In iron deficient regions,
adding iron to the oceans
might reduce global warming by: increasing photosynthesis and using up co2
20.
What is the use of RADAR. LORAN, and GPS?navigation
22.
What types of reefs form around islands?fringing,barrier, atolls
24.
How was the sea level different 15,000 years ago? Lower Why?Last ice age
26.
What evidence led to the acceptance of the theory of plate
tectonics/sea-floor spreading?magnetic/cores/sight
28.
What is a hydrothermal vent? Hot water returning to ocean floor Of what
importance are they?salts
30.
What is compensation depth?photo=resp
32.How does
hydrogen bonding increase waters ability to moderate ocean temperature?energy
must break bonds before temperature changes
Mar sci ocean floor/tect/chem. ODD ans
1. The crust under a continental shelf is
composed of:granite
3. Continental shelves are
primarily shaped when: sea level rises
5 A continental rise is made of sediment
primarily from:run-fall
off from the c/s
7. The superheated water associated with hydrothermal vents is moved by:convection
9Submarine canyons are most
often found on: continental shelf
11Hydrogen bonds are:weak
13Which atom(s)
in a water molecule usually have
a slight positive charge? H
15The major pH-buffering agents in the ocean are:carbonates
17 Is nitrogen is present in a higher percentage than oxygen or carbon dioxide yes
19. How is longititude
and latitude measured? degrees
21. Describe/name the features of the ocean
floor?
23. Why do trenches form?subduction zones
25. What force moves the plates?convection currents
27. What is a hot spot?
Magna burns through plates
29. The most important
physical factor limiting the distribution of ocean life is temperature
31. What are the sources of
salts in the sea?river
run-off---hydro vents