Ask a Marine Scientist:
answers to Oceanography questions!
Index To Questions
 Underwater
Sounds
Q: How do we know there
is sound in the water if we can't hear it.
A: Scientists have been
able to measure sounds that humans physically cannot hear.
Some sounds in the oceans are in a frequency range that our
ears cannot hear but they can be heard by scientific equipment.
This is true for many low frequency sounds that our ears cannot
detect.
However, there are many sounds in the oceans that we humans can hear. We can
sometimes (if we are lucky) hear a humpback whale singing. We can also hear
various sounds from Beluga whales, dolphins and so forth.
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Great
Tides
Q: What area on earth has
the greatest tides? Why?
A: The area on Earth that
has the highest tides is the Bay of Fundy in New Brunswick
in Canada. This area has the highest tides because of resonance
frequencies. Basically when the tide is coming in the wave
frequencies keep piling on top of one another and the tide
rises in this method.
A really simple explanation is what happens in a bathtub. When you slosh water
around in a bathtub (provided you time it correctly) you can eventually slosh
water right out of the tub. The tides in the Bay of Fundy are similar to what
happens in the bathtub.
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Importance
of Oceanography - Received from Doug in Texas
Q: i need 3 reasons as
to why oceanography is important and 3 specific jobs i could
get if i majored in it in a university thank you
A. There are a variety of
reasons why the science of oceanography is important. I'll give
you three, since that is how many you asked for.
1. Knowledge - The
more we know about the oceans, the better we will understand
the geological and biological history and processes that operate
on Earth. Oceanography helps us to understand our place in nature
and the processes that led to the evolution of life on Earth.
2. Weather - By studying
the earth's oceans we will be better equipped to predict patterns
of water movement, heating, cooling and evaporative processes
that directly affect weather systems. A better understanding
of the oceans will enable us to forecast dangerous storms such
as tornadoes and hurricanes.
3. Sustainability -
Oceanography is probably most important simply because there
are many unanswered questions about the oceans. The oceans are
very important to people and all of the life forms that live
on the Earth. A lot of our food, water and other important resources
come directly or indirectly from the oceans. By having a better
understanding of the ocean and the things that live there, we
can learn to properly manage marine resources. Oceanography can
help us to develop sustainable management plans for the marine
organisms and products that we use on a regular basis.
There are lots of different
types of jobs related to the field of oceanography. Here are
a few:
Oceanographic Engineer -
designs and builds equipment used by oceanographers and marine
scientists
Plankton Biologist -
studies the biology of the tiny organisms that float around in
the ocean. Plankton are very important because they supply most
of the atmospheric oxygen, and form the base of many marine food
chains.
Deep Sea Biologist -
study the animals that live in the deep sea. We don't know very
much about the animals that live in the deep sea. The environment
is unique, and a better understanding of the physiology, behaviour
and ecology of the animals that live in the deep will help us
to better understand evolutionary processes and the ocean environment.
There is lots more info on
the Career Info page on
the OceanLink website. I would check there for interviews with
marine scientists and other stuff like that.
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What
Does an Oceanographer Do? - from Rachel in Illinois
Q: I'm doing a report on
oceanography. Can you tell me what the definition of oceanography
is and what specific things an oceanographer might do?
A: Oceanography is the scientific
study of the ocean. Oceanography is a huge field and some of
the areas of study include: ocean bottom geographic features
(depths, volcanoes, trenches, oceanic plateaus, fracture zones,
ridges and basins), plate tectonics, chemical composition of
the ocean water (salt content, carbon dioxide levels, density,
etc.), interaction between the ocean and the atmosphere (coriolis
effect, weather systems, hurricanes, monsoons, cyclones, El Nino,
etc.), ocean climates, ocean currents, waves, tides, chemical
cycling in the ocean, plankton and sediments, just to name a
few. I suggest you also check out the OceanLink website under
the Career Info section
you will find an interview with Dr. Louis A. Hobson, an oceanographer
at the University of Victoria.
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Ocean
Facts - Received from L.Hensley in Greeneville,
TN
Q: I am starting a new
unit on Oceanography and Marine Biology for 4th grade students
participating in a pullout program for certified intellectually
gifted students. Research mentions 4 oceans, however several
sources mention Antarctica Ocean and Southern Ocean. I asked
my students to research this issue. Are there more than 4 oceans,
are there 5?
A: There are four main oceans:
the Pacific Ocean, Atlantic Ocean, Indian Ocean, and Arctic Ocean.
The Antarctic Ocean or South Ocean is a smaller ocean that some
books do not consider an ocean. But there are always difficulties
when humans try to define boundaries on something that has no
boundaries. Altogether there are five oceans, four major oceans
and one smaller, the Antarctic Ocean.
1. Antarctic Ocean:
Numerous sources talk about the Southern Ocean and the Antarctic Ocean and
they are the same area. The Southern or Antarctic Ocean is where the three
main oceans meet (the Pacific, Atlantic and the Indian) at Antarctica (the
continent). The Antarctic Ocean can be taken to include all oceanic areas
lying south of the Antarctic Convergence, usually around latitude 55 degrees
south.
Area: 13,513,000 sq. mi. or 35,000,000 sq. km
Area that is sea ice: 8,100,000 sq. mi. or 35,000,000 sq. km
Area that is permanently frozen: 1,540,000 sq. mi. or 4,000,000 sq.km
2. Pacific Ocean:
The world's largest ocean, covering one third of the earth's surface.
Area: 64,000,000 sq. mi. or 166,000,000 sq. km
Average depth: 14,050 feet or 4,280 metres
Volume: 173,625,000 cubic mi. or 723,700,000 cubic km
Maximum depth: Mariana Trench - 36,161 feet or 11,022 metres
3. Atlantic Ocean:
This ocean is much smaller than the Pacific Ocean but has a drainage area that
is four times larger than the Pacific.
Area: 3,166,000 sq. mi. or 82,000,000 sq. km
Average depth: 10,930 feet or 3,330 metres
Volume: 77,235,000 cubic mi. or 321,930,000 cubic km
Maximum depth: South Sandwich Trench - 30,000 feet or 9144 metres
4. Indian Ocean:
The world's third largest body of water and covers about twenty percent of
the total world ocean area.
Area: 28,400,000 sq. mi. or 73,600,000 sq. km
Average depth: 12,760 feet or 3,890 metres
Volume: 70,086,000 cubic mi. or 292,131,000 sq. km
Maximum depth: Java Trench - 24,442 feet or 7,450 metres
5. Arctic Ocean:
The smallest major ocean (remember the Antarctic Ocean is not a major ocean).
The area is slightly more than one sixth that of the Indian Ocean and it
has a basin that is almost totally landlocked.
Area: 4,700,000 sq. mi. or 12,173,000 sq. km
Average depth: 3,250 feet or 990 metres
Maximum depth: Pole Abyssal Plain - 15,091 feet or 4,600 metres
Reference:
"The Rand McNally Atlas
of the Oceans" 1977, Rand McNally & Company, Chicago.
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Q:
Why is the sea salty? (Received from Caitlin in Los
Angeles)
A: Thanks for your question. We've been waiting for someone to ask just this!
The salt that is in the ocean is actually comprised of a number of different
chemicals that are dissolved in the water, and are called "ions".
Six of these ions make up 99.36% of the weight of all of the ions in sea water.
These ions are: Chloride (Cl-), Sodium (Na+), Sulfate(SO4--), magnesium(Mg++),
calcium(Ca+) and potassium (K+). You'll notice that the two most common ions,
sodium and chloride make up common table salt (NaCl) when put together.
But where did these ions come from? As the rivers move to the ocean, they dissolve
the rocks that they pass over. Although this is a slow process, the rivers
have been flowing for a very long time!. The dissolved ions in the water make
their way to the ocean. When water evaporates from the ocean and falls on land
as rain, the ions are left behind in the ocean.
Does this mean that the ocean is getting saltier and saltier? No!
It is believed that the oceans of the world are about as salty today as they
were 1.5 billion years ago.
The ions are removed from the sea in a variety of ways. Calcium is removed
by animals that deposit it in their shells. An arm of a sea can become isolated,
and through evaporation, leave all of its salt behind (an examples are the
salt flats in Utah). The most important way that the ions are removed from
seawater is that ions can become "trapped" onto fine particles that
then drift to the bottom of the ocean to become sediment. They are then not
returned or redissolved into the seawater.
Hope this answered your question!
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Salinity
of the Atlantic Ocean - Received from Anneabeth in
New Jersey.
Q: What is the salinity
of the Atlantic ocean?
A: The
salinity of the Atlantic Ocean varies according to depth and
location. The highest salinity values are found in surface waters
at 20-30 degrees north and south of the equator, where evaporation
is high and precipitation is low. These values reach a maximum
of 37.3 parts per thousand (ppt) in the Atlantic Ocean. The lowest
salinity values are found towards the poles, where evaporation
is low and freshwater inputs from melting ice and precipitation
are high. The lowest salinity in the Atlantic is approximately
34.2 ppt in surface waters. Deep ocean waters are much less variable
in salinity, since they are not subject to evaporation or direct
freshwater inputs. Below 1000 m, the salinity is between 34.5
and 35.0 ppt at all latitudes.
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Measuring
Salinity - Received from Morgan
Q: Do you have anything
on salinity testing?
A. There are many methods
to measure salinity. Here are the most common methods:
1. Salinometer: this measures
the true salinity of the water.
2. Ions: you measure the amount
of ions in the water. The ions you measure are sodium(Na) and
chloride(Cl) which are the two ions that make up sodium chloride
(NaCl), salt. Other ions that can be measured are potassium(K),
magnesium(Mg) and sometimes calcium(Ca). By measuring theses
ions' concentrations you can get the approximate salinity.
3. Conductivity: you measure
the electrical charge that passes through ions in the water.
This method is the basis for the salinometer.
4. Refractometer: this method
measures the refraction of light through a sample of water. The
change in angle of the light changes as the salinity changes.
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Why
do we have oceans? - Received from Amber
Q: Why do we have oceans?
A: The reason why we have
oceans is because we live on a planet that is largely water based.
When the earth formed, water (or ice) made up a relatively large
proportion of the matter that was present. As a result, we now
have large oceans that cover almost 70% of the planet's surface.
It is a good thing too, because all of the beautiful living creatures
on the planet would not exist without water. The water in the
oceans evaporates and the precipitation that is produced sustains
almost all of the living things on Earth.
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Ocean
Origin - Received from Aaron Carter in Australia
Q: What were the origins
of the oceans. How were they formed and what forces and reasons
are involved in this process.
A: The Earth's oceans and
atmosphere were formed from volcanic activity. During volcanic
activity water and various gases are released from molten rocks
that erupt from volcanoes. The water released from these processes
are collected to ocean basins to form oceans. The Earth is large
enough to retain water and atmospheric gases, so that it has
both oceans, freshwater and an atmosphere.
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Mid
Ocean Rift (received from Arial in ???)
Q: What do scientists believe about the rift in the Mid-Ocean Ridge
A. We're not sure what you
mean by what scientists "believe" about the rift, but
we'll try to tell you what is know. The ridge system in the world's
oceans is a series of great continuous underwater volcanic
mountain ranges that stretch for 65,000 km around the world, running through
every major ocean. If you look at a map of the world ocean floor, you'll clearly
see this ridge system. The ridges are caused by
the movement of the Earth's crust due to continental drift. As the continental
plates drift, there are spreading zones where the crust is "pulling apart".
These zones are areas of intense volcanic activity,
which creates the mountain systems. In the center of each ridge is a rift zone
or rift valley. For example, Africa and South America are slowly moving apart.
The crust is breaking and spreading in the area of the Mid-Atlantic Ridge.
In the middle of the Mid-Atlantic Ridge is a rift valley, where the spreading
is taking place. This rift valley is the site of many hydrothermal vents (see
the OceanLink answers on this topic). The rift valley of the Mid Atlantic Ridge
was first seen by people in 1973, when the submersible Archimede travelled
to the site. In 1974, the submersible Alvin joined the study.
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Continental
Shelf Marine Life (received from Norman in Houston
TX)|
Question: I am working on a school project on marine biology. Why is it that
most life exists on the continental shelf
A. The continental shelf is
a nearly flat land-border of varying width that slopes very gently
toward the deep ocean basins. Shelf widths vary from a few meters
to more than 100 kilometres. They average 65 km in width. At
their seaward edge, the continental shelf is about 130 meters
below the surface of the ocean. At this point, the continental
slope drops off steeply to the ocean floor, which may be anywhere
from 3000 to 6000 meters deep. Most life in the ocean is in the
zone that receives sunlight, also called the photic zone (50
meters to 100 meters depth). This is because most marine life
(with a few exceptions) is entirely dependent on sunlight for
photosynthesis. The continental shelves are generally shallow,
and have lots of plant and animal life. No light penetrates to
the deep ocean floor, so no plant
life can occur there. Without plant life, the animals that live there are dependent
on other sources of energy. Recently, scientists have discovered some very
interesting animals that live in very deep areas
of the ocean. (see answers on hydrothermal vent animals). This shows that although
a great deal of marine life is found in continental shelf areas, there are
organisms in the deep sea - perhaps a few that have yet to be discovered!
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The
sulphur cycle - Received from Wendy in Waterloo, Ontario
Q: Could you tell me about
the sulphur cycle and the relationship between the cycle and
marine organisms?
A: If
you've ever been to a poorly drained sandy beach or a mudflat,
you couldn't help but notice the ripe egg smell from black deposits
below the surface. These are caused by hydrogen sulphide, one
of the products of the sulfur cycle.
When organic matter settles
on the bottom, the sulphur-containing proteins are broken down
into amino acids by specialized bacteria. These bacteria release
sulphides or sulphates as by-products, which are then metabolized
by other specialized bacteria, creating the sulphur cycle. This
goes on all over the ocean, but in areas of poor drainage, these
by-products accumulate in the mud or sand. These are called anoxic
layers because they are devoid of oxygen. The only animals that
can live in anoxic sediments are those that dig a tunnel to the
surface to get fresh water.
In some special cases, like
fjords, there is an under water ridge that only allows the relatively
warm upper layer of sea water into the system. Because the water
in the bottom of the fjord in cold, the new water stays above
it and never mixes with it. Then you have a biologically rich
layer in the middle and top of the water column, and a biologically
dead anoxic zone in the lower water column (because the bottom
is all sulphurous ooze.. In this way, the sulphur cycle can be
detrimental to marine organisms, especially those that live on
the bottom or feed on bottom dwelling organisms.
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Sulphate
Transport - Received from Jacki in Cleveland, OH
Q: Do you know of any papers
or books discussing the transport of sulfates inland from the
sea? My background is in geology and I currently am employed
in the concrete industry.
A. I have never heard of sulfate
transport inland from the sea. As far as I can recall, the transport
of sulfates is predominantly in the direction from land to the
oceans. Sulfates released into the atmosphere via combustion
processes, emissions from industry dissolve in precipitation
and are subsequently carried to the oceans in runoff. The only
other sulfate (actually sulphide) sources I can think of are
hydrothermal vent gasses. These are usually localized sources
along volcanically active seabeds (i.e. the Juan de Fuca Ridge
in the Pacific). However, I believe that the transport of these
sulphides are limited to deep waters in the vicinity of the vents.
I am unaware of any transport processes that parallel the one
you have described. You may want to ask someone at the Woods
Hole Oceanographic Institute or the Institute
of Ocean Sciences in Syndey, BC. There are links to these
resources through the OceanLink website.
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Artificial
Sea Water - Received
Dec. from Erica in Indiana
Q: I need to know for a
Science Fair project how to make sea water.
A: Here is the recipe for
making artificial sea water. If you have access to these chemicals
it is quite easy.
24.72 g NaCl
0.67 g KCl
1.36 g CaCl2·2H2O
4.66 g MgCl2·6H2O
6.29 g MgSO4·7H2O
0.18 g NaHCO3
Add dH2O to make 1 L
(Note: Add salts one at a
time. Always add sodium bicarbonate last.)
Good luck with your Science
Fair project.
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Marine
Climate (received from Tommy in Virginia)
Q: Hi! I need any info bout climates in the marine biome. In Charts or graphs!
ANY MARINE BIOME!!!!!!!
A. If you check out our page
of links to other marine sites you'll see a link to a site that
gives ocean buoy data from around North America. In addition
to recent data, this site also has data going back several months
that you can download. Check it out!
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Seasonality
in the Seas - received
from Linda in Coventry, Rhode Island.
Q: Does the sea have "seasons"?
On land leaves fall in autumn. What are the signs of the seasons
in the ocean? What happens during each? Where could I find out
more about this?
A: Great question! There sure
is seasonality in the seas. The seasons result from differences
in temperature, nutrient levels, and light that change over the
year.
Nutrients: In the winter,
nutrients (particularly nitrogen and phospherous) increase in
concentration in the highest layers of the water. This happens
because of increased upwelling (the movement of nutrient-rich
water from the deep parts of the ocean to the shallower parts),
and storms, which generally increase water movement.
Light: Daylight is shorter
in the winter, and the light is less intense, so it does not
penetrate as far down into the water. The changes in light conditions
are more dramatic in latitudes further from the equator.
Temperature: Water is warmer
in the summer, and may be lower in salinity (salt concentration)
because of freshwater run-off from the land.
These factors affect ocean
life in varying ways. Primary productivity (plant-life growth)
generally goes up during the winter because of the increase in
nutrients. Some plants store these nutrients and don't start
growing until the spring when there is more light. The seasonality
of the plant life affects herbivorous animals in the ocean, which
in turn affects all animals in the ocean foodweb.
As on land, seasons ocean productivity change more dramatically in polar regions
of the earth than near the equator.
An example of the effects of ocean seasonality is the migration of large animals,
such as whales. This happens because of the change in food productivity in
different latitudes at different times.
The best way to find out more about this is to look at some books about ocean
ecology, or primary productivity. An oceanography text book will have information
about primary productivity and the seasonality of the oceans. Also, books about
large migrating animals will have some information about seasonality.
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Ocean
depth and limiting factors (received from Steven in
Mississippi)
Q. Does the ocean have a corresponding general depth to mountain height (i.e.
12,000 feet) sort of timberline in reverse? Mountain sickness and the timberline
begins at 12,000 feet due to oxygen and temperature concerns, what about in
the ocean?
A. Interesting question! I will deal with your question in two parts. First,
lets look at marine life in the ocean. Whereas timberline is related to temperature
and exposure, the major limiting factor for plants in the ocean is light. As
visible light travels through water, the wavelengths begin to be absorbed.
In the clearest of seas, red wavelengths (the shortest) will be eliminated
within a few metres of the ocean's surface, while blue and indigo may travel
to 200 metres depth or more. Plant growth is limited by the available light
and which wavelengths of light can be utilized. Many red algae for instance,
have accessory pigments that allow them to use blue wavelengths of light. Red
algae therefore, are the deepest living plants in the ocean. Planktonic plants
must remain fairly close to the ocean surface. So I suppose an equivalent "timberline
in reverse in the ocean" could be around 200m or so (this depends on the
clarity of the water). Beyond 200m, there are no plants and the animals there
either eat other animals or eat detritus (feces, dead animals, etc.) or, as
is the case with hydrothermal vent communities, have a food chain driven by
bacteria and chemosynthesis, rather than photosynthesis. Since mountain sickness
relates specifically to humans, I am assuming that you are interested in an
equivalent sort of depth for humans in the ocean. (Marine animals have a variety
of adaptations (depending on the organism) that allow them to cope with pressure
changes). As you descend in the ocean, pressure increases by one atmosphere
for every 10 metres of depth. As a diver descends, they must breath air that
is at the same pressure as the surrounding water (e.g. trying to breath air
through a hose to the surface just won't work!) The development of SCUBA (specifically
a tank with compressed air and a pressure regulator in the mouthpiece) has
allowed divers to breath air that is delivered at pressure equal to that surrounding
them.
Divers can also becomes susceptible to the effects of dissolved nitrogen. At
depth, a diver breathes pressurized air, and gases become dissolved in the
blood and tissues. If a diver surfaces too fast, the dissolved nitrogen in
the body tissues can come out of solution, forming potentially dangerous bubbles
which may block blood vessels or may cause nerve damage. Nitrogen bubbles can
also lodge in the joints, causing a painful condition know as the "bends".
The problem of nitrogen bubbles is called decompression sickness and is treated
by immediately evacuating the diver to the nearest recompression chamber. Here
the patient is subjected to the same pressure as the deepest part of the dive,
and is brought very gradually back to the surface pressure (1 atmosphere) as
the diver breathes off excess nitrogen gas.
Physiological problems with humans in the ocean can occur at almost any depth,
depending on length and depth of the dive, exertion, equipment, etc. however
30 metres is considered a reasonable depth for sport divers. Beyond this (and
even before if the dives are long), divers must undertake decompression stops
during their ascent.
Answered by Adrienne Mason
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Ocean
Depth - received from Rodney in Marion, South Carolina
Q: As far as we know, how
deep is the ocean?
A: The ocean floor has an
average depth of 4 km, or 13000 ft - but a lot of the ocean is
deeper or shallower than that. In fact, the sea floor varies
quite a bit in depth, with topographic features analogous to
mountains and valleys on land.
Right off the edge of any continent is an area of relatively shallow ocean,
called the "continental shelf". The floor depth here is no more than
150 m (500 ft) below water level.
After the shelf, the depth falls to somewhere between 3 and 5 km (10000 and
16000 ft). These are the abyssal plains, which are interrupted with hills and
mountains where sediment has built up or submarine volcanoes exist.
Far out in the middle of the oceans, there is a belt of elevated floor called
the "mid-oceanic ridge." The depth here is between 2 and 4 km (6500
and 13000 ft).
The deepest parts of the ocean are deep-sea trenches, which are elongated trenches
that run along the edge of certain continental shelves. The depth here can
be from 5 to 12 km (16000 to 40000 ft)
These formations exist because of a process called "continental drift." The
earth's crust is made up of several plates that are slowly moving around; into
and away from each other. The deep-sea trenches are areas where one plate is
sliding down underneath another. The mid-oceanic ridges are areas where plates
are moving away from each other, and hot magma (molten rock from below the
crust) is rising to replace it.
The study of sea-floor topography is called bathymetry. You can find out more
about bathymetry and continental drift in an oceanography or geology textbook.
I found this information in "Invitation to Oceanography" by Paul
Pinet, 1998.
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Depth
of the Ocean (received
from Christopher in Missouri)
Q: What is the deepest ocean? How deep is it?
A. The deepest spot in all
of the oceans is The Challenger Deep, located in the Mariana
Trench, which is located between Japan and New Guinea. This spot
is 11,035 meters deep (36204 ft or 6.89 miles), which can be
compared to the height of Mount Everest at 8848 m (29028 ft or
5.53 miles).
Early mariners used a hemp
line with a weight on it to measure depth. Later, piano wire
with a cannonball attached to one end was used. This method was
so time consuming (8-10 hours to winch the line up and down)
that by 1895, only about 7000 depth measurements throughout the
world's oceans had been made in water greater than 2000 meters.
Today, information from depth recorders using sonar, as well
as observation by submersibles has enabled us to make very detailed
maps of the ocean floor. These maps may usually be found in any
good world atlas.
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Depth
Determination before Sonar -
received from Bill in Nantucket.
Q: How were depth determination
made before the invention of sonar?
A: This is a really great
question!
Before the invention of sonar,
Early mariners made depth measurements, called "soundings",
using a hemp rope marked in equal distances (usually "fathoms" which
was the length of a person's fully outstretched hands, or 6 feet).
With a lead ball on the end, the mariners would lower the rope
until the tension in the rope changes, indicating that the lead
ball had reached the bottom. If the covered the ball with grease
before the let out the line, they could pick up sediment from
the ocean's bottom (which would stick to the grease). This would
be another indication that they had hit the bottom, as well as
a way to sample what kind of terrain is underneath them.
This method worked fine for
shallow waters, but in deeper waters it was too difficult to
tell when the ball reached the bottom, because the hemp line
was so heavy. Later, piano wire with a connonball attached to
the end was used in deep water. The greater difference in weight
between the line and the weight made it easier for mariners to
tell when they hit bottom. The whole process was still rather
difficult, however, taking 8 to ten hours for a measurement.
The invention of the echo
sounder in the 1920s was great because it allows continuous depth
measurements to be made easily and quickly as the boat moves.
An echo sounder measures the time it takes for sound a pulse
to leave the boat, reflect off the sea floor, and return to a
hydrophone.
I found this information in an oceanography text book, called "An Introduction
to the World's Oceans" by Duxbury and Duxbury, 1994.
The measurement of depth in the ocean in order to map out the ocean floor is
called "bathymetry".
Thanks for the great question!
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Pelagic
depth zones - Received from Carrie in Massachusetts.
Q: I am teaching a 4th
grade class and we are studying the layers of the ocean and
the specific animals that live within each layer. If possible
could you provide the specific depths that 10 animals live
at (preferably animals from each layer). I greatly appreciate
it.
A: It
sounds like you're primarily interested in pelagic organisms
which inhabit the water column, and not benthic organisms living
on the sea bottom. The pelagic, oceanic environment can be broken
up into at least five "layers" according to depth:
epipelagic (0-200 m), mesopelagic (200-1000 m), bathypelagic
(1000-4000 m), abyssopelagic (4000-6000 m) and hadalpelagic (6000-11000
m).
Here are some examples of
different organisms living within each depth category:
Epipelagic
1) Emiliania huxleyi -
A species of coccolithophorid phytoplankton, E. huxleyi is
present in all the oceans except the polar seas. Coccolithophorids
are covered with many calcareous plates called coccoliths. After
forming large blooms, these organisms die and accumulate in the
sediment. Coccoliths are the major constituent of the white cliffs
of Dover. For some great pictures of E. huxleyi, check
out the Ehux
web site.
2) Velella velella -
Commonly known as the by-the-wind sailor, this small jellyfish
(3 cm wide) has a sail which projects above the water surface
to catch the wind.
Mesopelagic
3) Euphausia superba -
Commonly known as krill, E. pacifica lives in the Antarctic
Ocean and is the favourite food of baleen whales and crabeater
seals. Even though krill make migrations into the epipelagic
layer at night, they are considered mesopelagic because they
reside in this zone during the day.
4) Vampyroteuthis infernalis -
The vampire squid has jet-black skin, webbing between its arms
and eyes that can appear red under some light conditions. Despite
its name and appearance, however, the vampire squid is a very
docile animal.
Bathypelagic
5) Caulophryne sp.
- Female fanfin anglerfish have a "fishing pole" with
an artificial lure projecting off the front of their head. This
lure, which contains a light organ, attracts both prey and potential
mates.
6) Eurypharynx pelecanoides -
The gulper eel has a very large gape, weak jaws, tiny eyes and
a soft body. It is thought to behave like a living net, engulfing
prey (fishes and zooplankton) by swimming over them with its
mouth open.
Abyssopelagic
7) Cyema atrum - The
snipe eel reaches depths of 5100 m.
8) Melanocetus sp.
- The blackdevils are anglerfish which have been found to depths
of 4790 m. The males are very small and exist primarily for reproduction.
In many species, they live attached to the female.
Hadalpelagic
9) Coryphaenoides sp.
- This rattail fish was found between 6380-6450 m depth, and
is characterized by a light organ on its stomach.
10) Abyssobrotula galatheae -
This species of brotula was taken at 8370 m, and is the deepest-living
fish known. It has a large mouth, tiny eyes and feeds on bottom-dwelling
animals such as worms and isopods.
Its important to remember
that the animals which live in each zone are not necessarily
confined to that certain depth. These pelagic zones are human
classifications based on depth, temperature and chemical/biological
characteristics. There are many organisms which exist in more
than one depth level, especially those that undertake migrations.
For pictures of deep-sea fishes,
see the Sea and Sky Monsters of the Deep pages.
For information about human exploration of the deep-sea, check
out the Smithsonian page How
Deep Can They Go?
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The
Colour of the oceans (received from Jonathan
in New Jersey)
Q. Can you please give me some information about why the ocean appears in different
colors in different parts of the world?
For example: What gives it a blue or green color. And is the Red Sea really
red? If so why does it appear that way?
Thanks
A. What a great question!
First, we need to talk about what colour actually is! You probably know that
white light is composed of many different colours - you can see this when you
see a rainbow. (Normal) white light is composed of many different "wavelengths",
and each separate wavelength of light is a different colour. Long wavelengths
of light are red in color, and short wavelengths are blue. When you see an
object, and notice that is a particular colour, this is because the wavelengths
of that colour are being reflected back to your eyes. For example, if you see
a red ball, the shorter, blue wavelengths of light are being absorbed ("sucked
up") by the ball, while the longer, red wavelengths of light are being
reflected ("bounced back") into your eyes. Bet you never thought
that physics and marine science were connected!!!
Now, back to the ocean. When you look into a large quantity of pure, clean
water with no animals, plants or impurities in it, the water will absorb red
wavelengths, leaving the blue and blue-green wavelengths to reflect back to
your eyes. This is a natural property of water. The result is that pure water
is not really clear - if you have a lot of it, at great depth, it will appear
to be bluish. Of course, ocean water is not always pure. In coastal areas,
there is often silt or other suspended solids in the water, especially near
rivers. This will change the colour of the ocean water in these areas depending
on the colour of the suspended solids. Also, there are often "blooms" of
microscopic algae that occur in coastal waters, especially in temperate areas
near the coast. These "blooms" are composed of billions of individual
organisms, all of the same species. Each species has a particular colour, and
the net result is ocean waters that may be reddish, brown, or even turquoise.
A so-called "red tide" is composed of billions of organisms called
dinoflagellates that actually colour the water red.
The Red Sea received its name because of dense blooms of an alga with large
amounts of red pigment. The Gulf of California has been called the Vermilion
sea for the same reason. So, the Red Sea really is red!
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Secchi
Disk - Received from Jane in Victoria, BC
Q: I recently visited Bamfield
Marine Centre and I'm currently working on a project that related
to my trip. One of the days we went out and measured the quantity
of algae in Grapplers Inlet with a circular disc that was Black
and White. I was wondering what this piece of equipment was
called. Thank You very much
A.The device you used is called
a Secchi Disk, and is used to measure light attenuation (the
amount that is penetrating to water column). You used this as
an estimate of the amount of algal growth in the photic zone
from measurements of water clarity.
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Measuring
Turbidity - Received from Mia in Philadelphia
Q: What is the name of
the instrument you measure turbidity with?
A: Turbidity is the reduction
of water clarity due to suspended or dissolved materials in the
water column. Some methods used to measure turbidity are as follows:
1. Secchi
Disk: which is a flat circle-shaped disk painted black and white
that is attached to a rope. A Secchi disk measures the depth
at which light penetrates the water column. You measure light
penetration, by dropping the disk into the water and when it
disappears from eye sight that is the depth at which only 1%
of the total light left that entered the water at the surface.
The shorter the depth the more suspended particles, the higher
the turbidity of the water is.
2. Some
fancier equipment use optics that measure light between two distances
and turbidity of the water can be determined by the amount of
light present.
3. Using
a conductivity equation is a common method for measuring turbidity.
Conductivity is the amount of electrolytes (eg. NaCl, salt) in
the water. If you measure conductivity and light you can calculate
the turbidity in the water, because the amount of light that
is not absorbed by electrolytes is absorbed by suspended particles.
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Wave
formation - Received from George in Hawai'i
Q: How do waves form by
wind power?
A: When
wind blows across calm water, it stretches it, causing wrinkles.
The surface tension pulls back on the wrinkles to try and restore
a smooth surface (like the recoil of a spring or elastic band).
These two forces cause small waves on the surface called ripples.
As these ripples make the surface of the water rough, there is
more surface area and more bumps and ridges for the wind to "grip".
This means more energy can be transferred from the wind to the
water, which makes the waves bigger. If the wind is strong enough,
large swells will eventually form.
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Wave
Names - Received from Yvonne Warren in Flemington
New Jersey
Q: What is a low wave with
a smooth crest called? What is a wave that forms a large curl
called?
A: A smooth, long-crested,
longer-period wave is called swell. Whereas when waves forms
a large curl, the waves are losing their energy and are breaking,
and these are called whitecaps.
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Tides & the
Moon - Received from Robby Vido in Denver, Colorado
Q: I want to know about
what does the moons gravitational pull effect tide pools please
explain!!
A: The tide moves in and out
twice in a 24 hour period. When the tide is low that is when
tidepools exist. Tidepools are areas, kind of like little pools
in rocks (usually) that contain ocean water and a wide variety
of marine life when the tide is low (out). The tides are controlled
by the gravitational pull of both the sun and the moon, but the
moon is the stronger force. Remember that the moon rotates around
the earth and the earth rotates around the sun. The reason for
this is that the sun's gravity is stronger than the earth's and
the earth's gravity is stronger than the moon. The moon's gravity
pulls on all parts of the earth, but it's pull is most strong
on the side it is nearest to. The ocean is pulled out
slightly by the moon's gravity on the side of the earth that
the moon is closest to at that time. If you were to look at the
earth from space, there would be a bulge sticking out of the
earth on the side that the moon is on. There is also a bulge
on the opposite side that the moon is at and this is because
of the interaction between the earth and the moon creates another,
equal sized bulge on the other side of the earth. These bulges
are the earth's ocean being pulled towards the moon because of
moon's gravity. The bulges are also where the tides are the highest
and where the bulges are absent, that is where the tides are
lowest. As the moon changes position, the bulges of the earth's
ocean also moves along with with the moon. - see OceanLink's tides page!
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When
are tides the highest? (received from Scott at UBC)
Q: On what days of the year are the tides highest in this region?
We're assuming by your e-mail address that you're from Vancouver.
In general terms, there are two very high tide sequences per month - one during
full moon and one during new moon. These are the times when the sun, moon and
earth are aligned, and since the sun has an effect on the tides (46% of those
associated with the moon), the tides are highest when both moon and sun are
contributing to the tide. Tides during these periods are known as spring
tides. Note that spring tides do not necessarily have to happen only in
the spring months! They actually happen twice per month. The times when the
moon is located at right angles to the sun and earth produce low amplitude
tides known as neap tides.
In addition, the moon's orbit is not perfectly circular - it is elliptical.
This means that there are times when the moon is closer to the earth (perigee)
and further away from the earth (apogee). When a spring tide coincides with
a time when the moon at perigee, very high and low tides occur. In the Vancouver
region, this occurred around January 20-22, 1996, (16.4 feet high tide) and
will occur again around Dec 12-14, 1996 (16.3 feet high tide).
If you are interested in accurate tidal predictions, you should purchase a
copy of the Canadian Tide and Current Tables 1996, available at many bookstores
(probably at the UBC bookstore!).
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Outgoing
Tide Term (received from Michael in New York)
Q: What is the is the term used for when the tide goes out.
A. This is a pretty straightforward
question!. An oceanographer or marine biologist would say that
the tide was ebbing.
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Coriolis
Effect
Q: Can you explain the
Coriolis Effect?
A: The rotation of the earth
profoundly effects winds and currents. Humans do not experience
the effects of the earth's rotation because we are bound to the
earth's surface, whereas winds or currents move freely and are
not bound to the surface of the earth. Wind and currents are
deflected to the right of the motion (earth's rotation) in the
Northern Hemisphere and to the left in the Southern Hemisphere.
This deflection occurs because the wind and currents are on a
rotating surface. This effect is called the Coriolis effect.
If you are still confused, that's okay it's a confusing concept.
Let me example using another explain. If you are standing in
the centre of a giant turntable, that is NOT moving and you through
a snowball at the a target attached to the side of the turntable,
the snowball will follow a straight line and hit the target.
However, let's rotate the turntable and attached target counter-clockwise.
So now you are standing the centre of turntable that is rotating
counterclock-wise, like how it would be if you were standing
on the North Pole. Now if you throw the snowball at a target
directly in front of you it will not hit the target but will
be apparently deflected to the right. The snowball actually travelled
in a straight line, but because the target moved when the snowball
was is flight it appears to be deflected to the right. To imagine
being on the South Pole, merely rotate the turntable clockwise
and if you through a snowball now, the apparent deflection would
be to the left.
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Bermuda
Triangle - Received from Zac in Ohio
Q: What is the Bermuda
Triangle?
A: The Bermuda Triangle is
an area located in the North Atlantic Ocean, near the Gulf Stream,
where more than 50 boats and 20 airplanes have disappeared. It
is a triangular shaped area located roughly between latitude,
25 to 40 degrees north and longitude, 55 to 85 degrees west and
covers around 3,900,000 square kilometres (1,500,000 square miles).
Since the mid-19th century records of many unexplained occurrences
have been reported. Many ships have been found abandoned for
no apparent reason and others have sent distress signals and
were never heard from again. However, many planes and boats travel
through this area and nothing out the ordinary occurs. There
are various theories that attempt to explain the occurrences
in the Bermuda Triangle. One theory is that waves may interact
with currents, winds and other waves to form rogue waves. Rogue
waves can be enormous enough to break up and sink large ships.
But, no theory has been agreed upon, and perhaps more than one
theory applies to the Bermuda Triangle.
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Atoll
Formation - Received from Quynh Son in Phoenix,
Arizona
Q: How do you describe
the formation of an Atoll?
A: An atoll is a modified
ring-shaped reef that rise out of very deep water, far from land
and enclose a lagoon in the centre. Atolls are found mainly in
the Indo-Pacific area. There are many theories as to how atolls
form, but one theory stands out above the rest: the subsidence
or compensation theory.
The subsidence or compensation
theory was first described by Charles Darwin after his five year
journey on the Beagle (a boat). The theory goes that fringing
reefs (a reef near a land mass) grow on the shores of newly formed
volcanic islands. Volcanic islands are islands that were pushed
to surface from deep water. These islands often begin to sink
(subside), and if the sinking is not too fast, reef growth can
keep up with the sinking, forming next a barrier reef and finally
an atoll when island finally disappears under the ocean surface.
When the island disappears corals will continue to grow and keep
the reef at the surface. On the inside (remember atolls have
a central lagoon), where the island used to be, quiet water conditions
and high levels of sediments now exist there. These conditions
in the centre prevent fast coral growth and that is how the lagoon
is formed.
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Green
Flash
Q: What is "green
flash"?
A: I found some
info on green flashes! I hope it's not too late. Here's a great
site that you should check out: http://mintaka.sdsu.edu/GF/
It has links to photos, descriptions and explanations on all sorts of webpages.
Here's a quick description, but definitely check out that site:
Green flashes are real (not illusory) phenomena seen at sunrise and sunset,
when some part of the Sun suddenly changes colour (at sunset, from red or orange
to green or blue). The word "flash" refers to the sudden appearance
and brief duration of this green colour, which usually lasts only a second
or two at moderate latitudes.
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Ocean
Currents - received
from Samantha Day in Hornell, New York.
Q: How do ocean currents form
in the ocean? I am working on a school project and need help
with this question?
A: The water in the ocean
is always in motion.
It circulates around the world being pushed by powerful currents
like the Gulf Stream as well as small eddies. The large currents
are ultimately driven by the sun's energy. As water is heated
and cooled, and evaporation and freshwater input levels (from
rivers) fluctuate, the density of water will change. Warm, salty
water is less dense and floats on top of less salty, colder water.
This layering of the ocean will create a global ocean "conveyor
belt". Deep water moves in one direction and warm surface
currents move in the opposite direction and water is circulated
around the globe in this way.
For a really great description
of ocean currents check out this site at the Ocean Planet website
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Biggest
Ocean- received from Kalusa in South Carolina
Q: What is the biggest ocean?
A: The world's biggest ocean
is the Pacific Ocean. The Pacific has a larger surface area ,
a larger volume and a greater average depth than either the Atlantic
or the Indian Oceans. At the surface, the Pacific has an area
of 179 700 000 km2 and a volume of 723 700 000 km3,
with an average depth of 4028 m.
This info came from:
Introduction to the World's Oceans by Duxbury and Duxbury.
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First
Ocean Map - received
from Amanda in Florida
Q: Do you know who was the
first person to draw an ocean map?
A: This is not an easy question
to answer... Many people attempted to map the oceans, but their
attempts weren't truly accurate, and many of the historical maps
have been lost. Here are some important early oceanographers:
-the Astronomer Pytheas (4th century BCE): map of Atlantic ocean
-Ptolemy: mapped the Indian ocean as an enclosed sea
-Columbus, Vasco de Gama, and Magellan (1492-1522): great geographical discoveries
of oceans and continents
-Magellan mapped some of the ocean floor
-James Cook: discovered the continent of Australia, and many Pacific islands,
clarified inaccuracies in previous mappings
You can find more in depth descriptions of explorations and discoveries in
many books on Early Oceanography, or Historical Oceanography. One that I found
particularly interesting is called "Founders of Oceanography" by
Sir William Herdman written in 1923.
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Deepest
water temperature and salinity -
received from Erin in Clarksville, Tn.
Q: Whar is the relative temperature
and salinity at the deepest part of the ocean?
A: The deepest part of the
ocean is called the Challenger Deep, part of the Mariana Trench,
located southeast of Japan. This trench reaches a depth of 11035
m (36204 ft), which can be compared to the height of Mount Everest
at 8848 m (29028 ft). The temperature in the Mariana trench ranges
from 1.2-1.6 degrees Celsius and the salinity is around 36ppt
(parts per thousand).
What is amazing about the Challenger Deep is that people have only ever gone
down to 10900m. WOW!
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Volume
of the oceans -
received on from Stephen in Benicia
Q: What is the volume of
the oceans?
A: The volume of the oceans
put together is 1 370 300 000 km3. That is a whole
lot of water!
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Searching
the Ocean - received
on from Kayla in Wisconsin
Q: How do you search the
ocean?
A: That's an interesting
question. I guess it depends on what you are searching the
ocean for. If you are looking for surface dwelling creatures
such as whales the fastest way to survey the ocean is aerially.
Reserachers will often conduct aerial transect surveys to count
whale populations. This is when the researcher is in a helicopter
or small plane and they fly in straight lines a set distance
apart and observe what they see directly below them. Transect
surveys can also be done in boats, only they look to either
side of the straight line the boat travels. Transects are a
good way to save time because it would take you forever to
look at every single place in the ocean, it is simply too big.
If you are looking for fish or underwater creatures, you would
probably use radar or sonar from a boat and then scuba diving
once you've narrowed your search to a particular area. There
is also the possibility of using submarines or remote submersibles
to look for things in the ocean. If you are looking for underwater
geograhical features or sunken ships, you would probably use
sonar and then submersibles. New technology such as side scan
sonar helps in underwater detection too (this is called Bathymetrics:
surveying the seafloor).
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Settling
an Ocean bet -
recieved from Lisa in Arizona
Q: My friends and I have
a bet going... A few of us remember being taught that there
were five oceans, but others say there are only four. Looking
at atlases and in textbooks I realized that my other friends
were right and there are only four. Is it possible that there
USED to be five oceans and for some reason one got re-classified
or got grouped with another ocean? Is there a reason so many
people seem to think there are five oceans?
A: The terms and geographic
boundaries used in modern Oceanography are always up for personal
interpretation. The five oceans I assume you are referring
to are;
the Pacific, Atlantic, Indian, Arctic and Antarctic. A while back, there has
been a move in oceanography to consider the Antarctic Ocean just offshoots
of the Southern Pacific, Atlantic and Indian Oceans. Likewise, there are some
textbooks that will only refer to 3 oceans because they consider the Arctic
as an extension of the North Atlantic. So, basically where you want to draw
the lines between the oceans is up to you. It is hard to draw straight lines
in so much water and they are all connected anyway!
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Water
Pressure - received
from Micheal in Illinois
Q: Why is there so much
pressure in water?
A: The pressure that occurs
in water is actually the result of the mass of water. "Pressure" is
a term that is used to relate the mass of something to the
effect that it has on something else. In the case of water,
the mass of the water has an effect on the organisms that live
in it. Imagine for a moment that you are going to go swimming
in a pool. At the surface of the pool, before you get in, you
don't feel any pressure from the water, because you're body
doesn't feel any of the water's mass. If you get in and dunk
your head one meter below, your ears might pop because you
feel the mass of the water above your head. This is pressure.
If you then decide to go 2 meters below water, you have twice
as much water (and therefore twice the mass) above your head
as you had when you were only one meter below. You will also
feel more pressure. If you go 10 meters below water, or more,
your body will feel all the mass above you in the form of pressure.
The reason that this is a concern in water and in organisms
that live in water is that this pressure affects the gases
in our bodies, such as that in our lungs and in our ears. When
the pressure at large depths becomes too great, our bodies
have a difficult time adjusting to the change.
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Ocean
mapping - received
on from Lance in Texas
Q: I'm doing a project in
school on ocean mapping. I would like any info. that you can
give me.
A: Techniques for mapping
the ocean floor have changed quite a bit over the years. In the
late 1800's, oceanographers dangled weighted lines over the edge
of the boat, in order to determine how deep the water was. In
the 1920's, scientists learned to used echo sounders to map the
ocean floor. Pulses of sound were sent into the ocean, and then
the reflected signals were picked up by boats or submarines.
The size (diameter) of the reflected echo relates to the depth
of the ocean in that area. By the 1950's, the sounders were accurate
to within 2m, and by the 1960's there was enough data collected
to make a topographic map of the ocean floor. In the 1990's,
the use of SONAR (SOund NAvigation Ranging) became common for
mapping. A echo sounder is towed behind the vessel and sounds
out narrow sound waves, which reflect off of objects in the water.
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Hot
water volcanoes -
received on from Diane in Minnesota
Q: I am looking for information
about hot-water holes or volcanoes.
A: This question first requires
a little bit of background:
The Earth is divided into three layers: the crust (6-70km deep), the mantle,
and the core. The crust is divided into 12 different plates (like a giant jig-saw
puzzle!). As you go deep into the Earth, the temperature starts to increase.
As a result, the mantle is actually fluid, and flows underneath the Earth's
crust. As the mantle moves, the plates move with it. Where the plates are formed,
a ridge is created (Mid Atlantic Ridge) and where the plates collide, one plate
slides under another. The deepest spot in the ocean, the Mariana Trench, is
11km deep and occurs where the Pacific and Eurasia plates collide.
In the late 1970's a deep ocean submersible, called the Alvin, descended to
the Mid Atlantic Ridge. Scientists were amazed to find a series of underwater
volcanoes spewing hot water. These "smoking chimneys" emmitted high
concentrations of various metals and dissolved sulphide. Surrounding these
vents were diverse communities of tube worms, crustaceans, bacteria and fish.
The first hydrothermal vent community was discovered!
If you are interested in finding out more, try doing a web search using "hydrothermal
vents". Here is a couple of sites to get you started:
http://www.pmel.noaa.gov/vents/
Dive and Discover's Hydrothermal Vent page - see cool photos of vent animals!
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The
coldest spot - received
from Cassidy in Idaho
Q: How cold is it in the coldest
spot? Where is it?
A: In the ocean, temperature
decreases with increased depth. This is because light has a difficult
time penetrating the water. At the deepest places in the ocean,
temperatures reach near freezing (1.2-1.6oC).
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Tidal
errosion - received
on from Michael in England
Q: I need to find out about
coastal defenses to stop buildings falling into the sea due to
tidal erosion.
A: Coastal errosion can occur
for many reasons. Some natural forms of errosion occur due to
wave action and rising water levels (due to global warming, so
maybe it's not really natural!). Humans also contribute quite
often to errosion due to the building of different structures
such as dams (prevents sedimentation from travelling down a river),
building close to the coast, removing trees, building groins,
jetties, and breakwaters (designed to form protected bays and
to reduce wave action and errosion, but often end up causing
errosion further down the coast by preventing the movement of
sediment). Statistics state that 40% of American shores are receiving
less sedimentation than they lose. Errosion problems are very
difficult to fix, and very costly. Some solutions are transporting
sediment from other regions, or shunting sediment from one side
of a breakwater to the coast on the other side. Unfortunately,
I am not an engineer and I am not familiar with specific building
structures used to prevent errosion. I suggest contacting an
engineering department at your local university to see if someone
there can help you further. Here are a couple of websites that
maybe useful as well:
Centre
for Coastal Studies, University of California, San Diego
USGS
Coastal and Marine Geology Program
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Miscellaneous
cool marine facts -
received from Ranger Rick Magazine
Q: A. About how many gallons
of water can a pelican scoop up in its bill?
B. How many minutes can a sperm whale hold its breath underwater?
C. How many eggs can an ocean sunfish lay at one time?
D. How many bones are in a shark's body?
E. About how many suckers does a common octopus have?
F. About how many miles per hour can a sailfish swim?
G. How many inches long is an adult pygmy shark?
A: A. 17 pints (2.55 gallons)
B. 90 minutes
C. 300 million eggs - a world record!
D. 0 - a shark's skeleton is made of cartilege!
E. 8 arms, with 240 suckers on each arm = 1920 suckers
F. 68.18 mph
G. Between 7-10"
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Varying
Ocean Color
Q: Why is the ocean color
different from Florida to Virginia? My 11 year old nephew wants
to know.
A: Your nephew sounds very
inquisitive. From the information i gathered the different ocean
colors are a result of different levels of a tiny organism called
phytoplankton. Sea color where there are lots of phytoplankton
will be a greenish/blue while sea color in areas of lower phtyoplankton
density will be dark blue nearly black. Its pretty amazing that
an organism the size of a phtyoplankton (you need a microscope
to see them) can change the sea color. A second way for oceanic
color change to occur is related to sand color. An shallower
ocean with a whitish sand bottom will appear a lighter blue than
one with a darker sand bottom.
Thanks for the great question.
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Dissolved
Substances in Seawater
Q: Why can you find traces
of all naturally occurring substances in seawater and why do
these concentrations differ from rivers to the ocean?
A: To answer your first question
water can dissolve or be a transport medium to virtually any
dissolved substance on the planet. The dissolved substances eventually
reach the ocean. The industrial processes allow for much more
dissolved substances to reach the ocean such as heavy metals
metals (Eg mercury) and so forth. The ocean is also a dumping
ground for potentially thousands of man-made chemicals as well.
To answer your second question concentrations of dissolved substances are higher
in a river than they are in the ocean. When dissolved substances in a river
meet the ocean they are diffused into a much larger body of water this lowering
the concentration of the substance. A simple explanation is to take a glass
of salt water and pour it into a full bathtub. The bathtub water has the same
amount of saltwater that was in the glass but its over a larger area thus lowering
the concentration of salt.
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Ocean
Color Variation
Q: Why
are the tropical oceans a lighter blue color while the temperate
oceans are a much darker blue?
A: From the information i gathered
the different ocean colors are a result of different levels of
a tiny organism called phytoplankton. Sea color where there are
lots of phytoplankton will be a greenish/blue while sea color
in areas of lower phtyoplankton density will be dark blue nearly
black. Its pretty amazing that an organism the size of a phtyoplankton
(you need a microscope to see them) can change the sea color.
The second way that the ocean can have a different color is dependent on the
color of the sand on the ocean floor. This is only for areas that are relatively
shallow however. If in a shallow area the bottom has white sand the ocean color
will be a light blue to a pale blue green.
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Oeaanic
Gas Hydrates
Q: What exactly are oceanic gas hydrates
and much reserves are there in the world? I heard that the BBC
(British Broadcasting Company) stated that has hydrates represent
80000 times the existing natural gas reserves.
A: I did not have a clue that these
deposits of hydrates existed at all. Gas hydrates are balls of
frozen methane on the ocean floor. They occur at very deep depths.
I am pretty sure that the BBC was being truthful when they stated
that hydrates could represent 80000 times the natural gas reserves.
The United States geological survey estimates that the hydrates
off the coast of North Carolina alone represent 350 times the
total use of energy in the U.S. in a given year. This represents
an incredible source of energy. However its very expensive and
dangerous to extract them from the ocean floor. It may be possible
later in this century and into the next one to extract these
reserves but it will not occur until we have exhausted present
reserves or cost of present extraction is to high. There are
also existing large oil reserves that we can extract such as
the tar sands and so forth.
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Scuba
Equipment
Q: Is there Scuba diving equipment
for overweight people?
A: Most scuba diving equipment
stores will sell custom fitted scuba gear. The only downfall
of custom fitted gear is that it will cost more. However it will
be worth it in the long run if it fits better.
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Different
Beach Types
Q: Whe are beaches different in some
parts of the world?
A: A lot of the time the beach type
is determined by materials that are readily available for beach
formation. In this way a very rocky shore may have a rocky beach.
If the near beach materials are sandy the beach will likely be
sandy as well. An example is beach development where beaches
are formed by the weathering of valcanic lava flows. These beaches
usually have very black sand. In other cases longshore drift
of sand materials can create sandy beaches. In areas where longshore
drift is altered by development (such as harbor development)
the beaches can be altered to the point where a new sandy beach
may develop in place of an older one.
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Different
Types of Sediments
Q: What are the different types of
sediments on the ocean floor?
A: There are five different types of
major sediment groupings. I will go over each of then in turn.
1. Terrigenous or land based sediments. These sediments are from the weathering
and erosion of land based rocks and minerals.
2. Biogenic sediments. These sediments are from the decay of things such as
animal skeletons, shellfish shells and animal teeth.
3. Cosmogenous sediments. These sediments are from debris from outer space
and the rarest of all Earth's sediments.
4. Hydrogenous sediments. These sediments are from chemical and biochemical
reactions on the ocean floor. An example is manganese nodules on the ocean
floor.
5. Volcanogenic Sediments. These sediments are from volcanic ash fallout and
so forth.
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Undersea
Diamond Mining
Q: Since there is vast amounts
of oil reserves in the ocean basins I was wondering if there
were diamond reserves as well. Is it possible for undersea diamond
mining to occur if there are diamonds on the ocean floor?
A: I have done some research
and was surprised with what I found. Diamond mining is actually
taking place right now in the oceans along the African Coast
(namely around Namibia) to depths of around 600-700 feet. These
diamonds appear to have been deposited thousands of years before.
According to an article that I read the technology is improving
rapidly and there will be some expansion in the near future.
further information indicated that this type of undersea mining
has been going on since the 1960's but a lack of sophisticated
technology made the work costly and difficult to manage. If you
can find diamonds in the ocean it makes you wonder what else
you can get from down there doesn't it?
Hope I answered the question. This news story will give further information regarding
minerals on the ocean floor.
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Difference
Between Sea and Ocean
Q: What is the difference
between a Sea and an Ocean and why the distinction?
A: Seas are just extensions
of an ocean. For the most part seas are indentations of the larger
ocean body into a continent. Seas can be partially or totally
landlocked. An example of a large sea is the Mediterranean which
is an extention of the Atlantic Ocean. The Mediterranean is fairly
landlocked with major choke points at the Straits of Gibraltar
(entrace off the coast of Spain) and the Dardanelles (exit to
the Black Sea). Sometimes seas can be totally landlocked within
a continent such as the Caspian Sea in the middle of the old
Soviet Union. Landlocked seas have salt-water. The worlds largest
lakes are not seas because they have freshwater instead of saltwater.
A sea becomes an ocean when its not confined by the land masses. For example
when the Mediterranean exits into open water it becomes the Atlantic Ocean.
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Ocean
Maps Getting More Accurate?
Q: Why does an oceanographer's
map of the ocean floor get more accurate as more sonar reading
are taken?
A: Well there a few reasons
why maps of the ocean floor keep getting better. First off sonar
keeps improving and scientists can get a more accurate reading
of the ocean bottom. Secondly many of the older maps were made
with older sonar systems that were not as accurate as todays.
In some areas there may not even be accurate sonar data at all.
Also the ocean bottom can change in an area over time with new
sediments added, sediments that shift from ocean currents or
underwater earthquakes and so forth. As time progresses however
the date just keeps getting better. The unfortunate part of it
all is that getting sonar data is expensive so updating charts
can take a long time to occur.
Quantum
Metre
Q: What is a quatum meter?
What is a Salinometer?
A: A quantum meter is designed
to analyze PAR (Photosynthetically Available Radiation). Basically
the quantum meter analyzes the amount of light energy that a
plant can use to create usable energy. The salinometer is an
instrument (on the principle of a float) for measuring the degree
of salinity or the concentration of the brine or seawater.
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