OCEANOGRAPHY

Oceanograph
y
 Is a composite science
that draws on the methods
and knowledge of biology,
chemistry, physics, and
geology to study all
aspects of the world
ocean.

The Vast World
Ocean
The world ocean covers 71 percent of
the earth’s surface, or about 361
million sq km (140 million sq mi).
Its average depth is 5,000 m (16,000
ft), and its total volume is about
1,347,000,000 cu km (322,300,000 cu
mi).

Size: How big is the Pacific Ocean?
With a surface of
169,479,000sqkm/65,436,200sqmiles it provides
almost half of the Earth’s water area. Did you know
that the size of the Pacific Ocean is bigger than the
total size of the landmass of all the continents
together?
Depth: How deep is the Pacific Ocean?
 The average depth is about 3,800 m. The
Challenger Deep in the Marina Trench, which is
located to the West of the Philippines and north of
New Guinea, is the deepest point in the Pacific
Ocean with 10,920m/35,827ft.

There are many islands in the
Atlantic Oceans, among the most
well-known are:
•The Bahamas
•Canary Islands (Spain)
•Azores (Portugal)
•Cap Verde Islands
•Greenland, which not only is the
largest island in the Atlantic Ocean,
but also on earth.

Atlantic Ocean Islands: The
Bahamas

 Size: How big is the Atlantic Ocean?
The Atlantic is the world’s second largest ocean
and covers 25% of the Earth’s surface, after the
Pacific Ocean. In size the Atlantic Ocean is
comparable with roughly 6.5 times the size of
the USA.
 Depth: How deep is the Atlantic Ocean?
The greatest depth is the Milwaukee Deep in
Puerto Rico: 8,605 metres. The average depth
is about 3,339 metres (10,955 ft

There are many islands in the
Indian Oceans, among the most
well-known are:
•Mauritius
•Reunion
•Seychelles
•Madagascar
•The Comores (Spain)
•Maldives (Portugal)
•Sri Lanka, formerly known as
Ceylon

 Size: How big is the Indian Ocean?
The Indian Ocean is the world’s third largest
ocean and covers 20% of the Earth’s surface,
after the Pacific and the Atlantic Oceans. In
size the Indian Ocean is comparable with
roughly 5.5 times the size of the USA.
 Depth: How deep is the Indian Ocean?
The lowest point is in the Java Trench which
is about 7,258 metres (23,812ft.) deep. The
average depth is about 3,890 metres (12,762
ft.).

 The Arctic Ocean (also known as the Northern
Ocean), located in the Northern Hemisphere
and mostly in the Arctic north polar region, is
the smallest and shallowest of the world's five
major oceanic divisions.
 Antarctica is colder than the Arctic. The
lowest temperature recorded there was –
89.2C (–90.4F)
 The Arctic Ocean covers 5.4 million square
miles, which is more than the area of Europe.

Seawater is a complex solution of salts,
consisting of about 3.5 percent (by
weight) dissolved mineral substances.
If all of the water were evaporated from
the oceans, a layer of salt approaching
60 meters (200 feet) thick would cover
the entire ocean floor.

Salinity and Its
Variation
What is Salinity?
 is the measure of all the salts dissolved in
water.
usually measured in parts per thousand (ppt
or ).
The average ocean salinity is 35ppt and the
average river water salinity is 0.5ppt or less.
This means that in every kilogram (1000 grams)
of seawater, 35 grams are salt

MIX:
Sodium chloride (NaCI) 23.48 grams
Magnesium chloride (MgCI ) 4.98
Sodium sulphate (Na SO ) 3.92
Calcium chloride (CaCI ) 1.10
Potassium chloride (KCI) 0.66
Sodium bicarbonate (NaHCO ) 0.192
Potassium bromide (KBr) 0.096
2
2 4
2
3
Hydrogen borate (H BO )
Strontium chloride (SRCI )
Sodium fluoride (NaF)
3 3
2
0.026
0.024
0.003
Recipe for artificial
seawater
Add:
Water (H O) to form 1000 grams of2

 Chemical weathering of rocks on the
continents is one of the source.
 The second major source of elements
found in the ocean water is Earth’s interior.
 Outgassing- (sometimes called offgassing,
particularly when in reference to indoor air
quality) is the release of a gas that was
dissolved, trapped, frozen or absorbed in
some material

The Ocean’s
Layered
Structure

1. Photic zone- In this layer, there is more
interaction with the surface. Also water
is being constantly evaporated, and its
where there is most ocean life.
2. Pycnocline- In this layer is where the
thermocline is and where density drops
rapidly with depth. This is a thin layer
where the two other layers interact.
3 major ocean layers:

3. Deep layer - In this layer the water is
cold and dense. There is the least
amount of life there too.

 From Dec. 1872 to May 1876, the Challenger
expedition made the first, and perhaps still
most comprehensive, study of the global
ocean ever attempted by one agency.
 The 11,000- kilometre (68,000 mile) trip took
the ship and its crew of scientists to every
ocean except the Arctic.

Oceanographers studying the topography
of the ocean floor have delineated 3 major
units:
1. Continental Margin
2. Deep-ocean Basins
3. Mid-ocean Ridges

2 main types of continental
margin:
Active
Passive

Continental Shelf-
is a gently sloping submerged extending
from the shoreline toward the deep-ocean
basin
On the average, the continental shelf is
about 80 kilometres (50 miles) wide and
130 meters (423 feet) deep at its seaward
edge.

Continental slope- a relatively steep structure (as
compared with the shelf) that marks the boundary
between continental crust and oceanic crust.
Continental Rise- the slope drops to about one-third
degree, or about 6 meters per kilometre.
Consists of a thick accumulation of sediment that moved
downslope from the continental shelf to the deep-ocean
floor

Located on either side of the mid-ocean
ridge is the ocean basin.
It is made up of low hills and flat plains.
This is the deepest part of the ocean floor.

Deep-ocean Trenches- are long, relatively narrow
features that form the deepest parts of the ocean.
The Mariana
Trench or Marianas
Trench is the
deepest part of the
world's oceans. It is
located in the
western Pacific
Ocean, to the east
of the Mariana
Islands.

Challenger Deep
The Mariana Trench in the Pacific Ocean is the lowest point on Earth. Its
deepest part, called the Challenger Deep, is almost 7 miles (11
kilometers) below the ocean surface. The submarine vessel shown here,
named the Trieste, became the first vessel to reach the bottom of the

Abyssal plain- are incredibly flat features; in fact,
these regions are likely the most level places on
Earth
Seamounts- is a mountain rising from the ocean
seafloor that does not reach to the water's
surface (sea level), and thus is not an island.

Mid-ocean ridge
On the bottom of the ocean, there is a central
ridge, or mountain range, that divides the ocean
floor into two parts.
These underwater volcanic mountains are
known as the mid-ocean ridge.

Marine Life
Zones and
Habitats

Life Zone Subdivision characteristics
based on the available light
Photic has light
Euphotic has enough
for photosynthesis
Aphotic no light
based on distance from shore
Intertidal bet. tidelines,
waves hit shore
Neritic above continental
shelf, rich in biodiversity
Oceanic open ocean,
beyond shelf break

based on depth
Pelagic all water above ocean
floor, organisms swim
or float
Benthic bottom of ocean,
organisms attach to,
or crawl on seafloor
Abyssal deep-sea bottom, dark,
cold, high pressure

OCEANOGRAPHY

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