After attending this lesson, the learner should be able to comprehend about the geographic setting of the Pacific ocean, its dimension, associated water masses, morphological features of the ocean floor, very significant conditions of the ocean, sediments, marine life, marine pollution and other hazards. In addition the user should be able to understand, the importance of the Pacific in the context of global activities including the historical oceanographic explorations.

1. Topic of the lesson
The Pacific
Ocean
By
Prof. A. Balasubramanian
Centre for Advanced Studies in Earth Science
University of Mysore, India

2. 1. Introduction
2. Historical explorations
3. Crustal plates
4. Profile of the ocean floor
5. Sedimentation
6. Water masses and
Temperature
7. Climate
8. Ecological zones
9. Economic mineral
resources
10. Marine pollution
Table of Contents

3.  After attending this lesson, the learner should be
able to comprehend about the geographic setting
of the Pacific ocean, its dimension, associated
water masses, morphological features of the
ocean floor, very significant conditions of the
ocean, sediments, marine life, marine pollution
and other hazards. In addition the user should be
able to understand, the importance of the Pacific
in the context of global activities including the
historical oceanographic explorations.
The Objectives

4.  The world’s oceanic water masses occupy about
97 per cent of the hydrosphere. The remaining
three percent, is frozen in the form of icecaps
and distributed in the lakes, rivers, subsurface
aquifer, and as water vapour. The seas and
oceans cover about 70% of the surface of the
Earth, which is equal to 361.1 million sq.km in
area.
Introduction

5.  Oceanic water masses are fully connected and
interlinked with each other. If we physically look
at these, there is only one water mass existing in
the world.
 The presence of various continents, divide the
world’s water mass into five major oceans.
They are, the Pacific Ocean, the Atlantic Ocean,
the Indian Ocean, the Arctic ocean and the
Antarctic ocean.
One water body as a whole

6.  Each one of these large oceans, include many
smaller water bodies as seas, gulfs, or bays and
straits.
 Among these, the Pacific Ocean is the largest
and the deepest ocean in the world.
Understanding of the oceanography of the
Pacific, is an interesting topic.
Water Tentacles

7.  The term “Pacific”, is derived from the Latin term
"Mare Pacificum", which means "peaceful sea".
 Geographically, the Pacific Ocean alone covers
about 32% of the Earth's surface.
 The surface area of the Pacific ocean is greater
than that of all land areas put together.
Geographic Setting
(…Contd)

8.  The Pacific extends from the Arctic of the north
pole to the Antarctic regions of the south pole.
 This ocean is bounded by the North and South
America on the east. It is bounded by Asia,
Japan, Australia and the new Zealand on the
west.
 The Pacific Ocean is known for its enormous
biological resources and geological features.
Geographic Setting

9.  The Pacific ocean is linked with the other water masses
through straits and passages.
a) It is linked with the Arctic Ocean through the Bering
Strait.
b) It is linked with the Atlantic Ocean through the Drake
Passage at the southern end of South America, Straits of
Magellan, and finally, through the Panama Canal.
c) The Pacific Ocean is linked with the Indian Ocean
through the passages like Malay Archipelago, Torres
strait existing between Australia and Papua New Guinea.
Links with other water masses

10.  The Pacific is a very vast ocean, covering
individually, about 165 million sq.km.
 Along with its other marginal seas, the it covers
an area of about 180 million square kilometers.
 Its maximum length along the north–south
direction is about 14,500 km.
 Its maximum width along the east-west
direction, is about 17,700 km.
Dimension
(…Contd)

11.  That is seen between the Isthmus of Panama and
the Malay Peninsula.
 It extends approximately 15,500 kilometres from
the Bering Sea, in the North pole, to the southern
tip of the globe. The Pacific has its greatest, east-
west width, at about 5 degree North latitude.
 It stretches for about 19,800 kilometres from
Indonesia to the coast of Colombia and Peru.
 This distance itself, is halfway across the world.
Dimension

12.  The equator subdivides the Pacific ocean into the
North Pacific Ocean and South Pacific Ocean.
 The Pacific ocean is a historically significant part in
the world. The Pacific plays its role in classifying
the World Time Zones.
 The 180 degree Meridian passes through the
Pacific. It is called as the international date line. It
is where each day begins.
The Equator and International Date Line

13.  The Pacific Ocean is the deepest ocean, in the world.
The mean depth is 4280 m.
 Its greatest depth, lies within the Mariana Trench and
the Japan Trenches.
 These two are the world ‘s deepest trenches, reaching
a depth of more than 10 km.
3 Depth
(…Contd)

14.  The Mariana Trench lies in the western North
Pacific ocean with a depth of 10,911 metres below
sea level.
 The deepest parts of the Pacific are also very
closer to the shores of land masses.
 They include the Japan and Kuril trenches, which
border the island chains of the Western Pacific.
3 Depth

15.  The water tentacles of the pacific are called as
oceanic arms. The principal arms of the Pacific
Ocean are
a) the Bering Sea in the north
b) the Gulf of California in the east
c) the Ross Sea in the south; and
d) the Sea of Okhotsk, the Sea of Japan, and the
Yellow sea, East China sea, South China sea,
Philippine sea, Coral sea, and Tasman sea in the
west.
Principal Arms

16.  The total volume of all oceanic waters, in the
globe, is about 1370 million cubic kilometers.
Out of which, the volume of water existing in the
pacific Ocean is about 714.410 million cubic.km.
 This is about 53% of the total volume of water of
all the oceans put together. Much of the
freshwater to the Pacific also comes from a few
large rivers like the Columbia of North America
and the Huang He, Chang (Yangtze) of China.
Volume of water

17.  About 3000 years ago, seafarers started their
voyages in the oceanic world.
 The famous and remarkable ancient
explorations were started by the Greeks,
Chinese, Europeans, Romans, Asians, the
British and the Portuguese.
 The Portuguese explorer, Ferdinand Magellan,
named this great oceanic water mass, as the
Pacific Ocean.
Historical Explorations

18.  The Ocean Explorations had several reasons to the study
of the Pacific Ocean, in depth.
 The early migrants have crossed the long distances of the
open Pacific ocean, using primitive boats.
 The islands of the south and west Pacific, were populated
by migrants. Most of them were from the Asia.
 The European travellers, including Marco Polo, had
reported an ocean off Asia, in the late 15th century. Some
trading ships had also sailed around Africa to the western
rim of the Pacific, during this time.
Explorations and Migrations

19.  The true recognition of the Pacific, as a distinct
ocean, from that of the Atlantic Ocean, came after
Balboa's sighting of its eastern shore, during the
year 1513.
 Magellan's crossing of the Philippines, during the
year 1520-21, initiated a series of explorations.
 The notable ones were, the explorations of Drake,
Tasman, Dampier, Cook, Bering, and Vancouver.
Sixteenth Century Explorations
(…Contd)

20.  These went upto the end of the 18th century.
 All these explorations had mainly disclosed the
nature of the coastline and the major islands of
the Pacific to the other parts of world.
 In the 16th century, the supremacy in the Pacific
region was shared by both Spain and Portugal.
Sixteenth Century Explorations

21.  The English and the Dutch have established
the footholds in the Pacific, during the 17th
century.
 The France and Russia have done some
expeditions during the 18th century.
 The people of Germany, Japan, and the United
States have done their works during the 19th
century.
After Seventeenth Century
(…Contd)

22.  The Pacific Ocean has its own history in the
history of the world.
 It is because of these world famous voyages
and explorations of Pacific Islanders, it was
possible to acquire all practical knowledge
about oceanography, over these years.
After Seventeenth Century

23.  The 1494, the Line of Demarcation was done to
establish the boundary between the Atlantic and
Pacific Oceans.
 The Portuguese and the Spanish together
explored the vastness of the Pacific Ocean over
a period of time.
 In 1520, Ferdinand Magellan conducted an
expedition with three ships .
Ferdinand Magellan
(…Contd)

24.  They sailed out of the stormy passage of the
strait at the southern tip of South America into
the Pacific Ocean.
 It was Magellan who named the Pacific as a
peaceful, calm, quiet ocean. Magellan's
voyages were followed by several voyages
from the western coasts.
Ferdinand Magellan

25.  The Dutch Explorations are also very notable
ones. Dutch explorers looked mainly for profit in
the Pacific ocean for its trade.
 The British also did notable Explorations of the
Pacific. In 1765, Byron sailed into the Pacific
Ocean and declared that two northern islands
were belonging to the British.
Other explorers
(…Contd)

26.  They are the Tuamotu Islands and Pukapuka
in the northern Cook Islands.
 In 1768, Captain James Cook (1728–1779)
sailed on his first voyage to the Pacific.
 Cook proved that the two islands of New
Zealand were definitely not part of some larger
southern continent. They are independent.
Other explorers

27.  The people of the ancient explorations, gave the
details of the major oceanic currents, prevailing
wind patterns, and the other features of the
Pacific. It was due to these voyagers, we could
get the details of
a) equatorial counter current,
b) the great northern whirl,
c) the great southern whirl, and
d) forecasting of all wind seasons.
Inputs from the Explorations

28.  According to the theory of plate tectonics, the
earth's outer shell consists of huge rigid plates.
 The plates are of two types as oceanic plates
and continental plates.
 Although continental plates are located under the
continents, they usually extend into the ocean as
well.
Crustal plates
(…Contd)

29.  Only small continental plates, like the Turkish-Aegean
Plate, do not extend into the ocean.
 Oceanic plates are located under the oceans. There are
three major oceanic plates.
 The smallest of the three, the Cocos plate, is located
west of central America.
 The largest plate is the Pacific plate. It spans over most
of the Pacific ocean.
 The third one is the Nazca plate. It is located west of
South America.
Crustal plates

30.  The plates were initially together. The Plates move
away from one another along the divergent plate
boundaries.
 At the same time they must move toward one another
along the convergent plate boundaries, elsewhere.
 As the plates move, they carry the ocean floor and the
continents with them.
 The relative movement of two neighbouring plates is
generally about 1 to 10 centimetres a year.
Plate tectonics
(…Contd)

31.  When two plates collide each other, one plate
may pile up against the other.
 This created the underwater mountains.
Sometimes, one plate may be drawn down into
the mantle under another plate.
 Such action produces deep oceanic trenches
and generate volcanic eruptions.
 Earthquakes may also occur near these plate
boundaries.
Plate tectonics

32.  Different movements of the plates have different
effects on the ocean bottom.
 Sea-floor spreading--and the formation of new
sea floors--occur where the plates move apart.
 The mid-ocean ridges also mark the existence of
such zones.
Impacts
(…Contd)

33.  The Pacific Ocean is currently shrinking due to
the theory of plate tectonics.
 It shrinks by roughly an inch per year (2–3 cm/yr)
on 3 sides.
 It amounts to an average of 0.5 square km a
year, the ocean is shrinking.
Impacts

34.  The ocean floor is a region of spectacular
morphology and contrasting relief features.
 Beneath the sea there are broad plains, towering
mountain chains, undersea volcanoes, deep
trenches and valleys.
 The morphology of the pacific consists of a vast
continental shelf, continental slope and a deep
ocean basin.
Profile of the ocean floor

35.  The continental shelf is the submerged land at the
edge of the continents.
 It begins at the shoreline and gently slopes
underwater to an average depth of about 120 to 130
metres.
 The width of the continental shelf averages 75
kilometres.
 The edge of the continental shelf occurs extends to
a depth of 20 to 550 m, averaging 130 m.
Continental shelf
(…Contd)

36.  The continental shelves of the Pacific, consist of
huge deposits of sand, mud, and gravels.
 There is a vast thicknesses of consolidated
sedimentary rocks, overlying crystalline rocks.
 The edge of the shelf is called as the shelf break.
 It is characterised by an abrupt increase in the
slope to an average of about 4 degrees.
Continental shelf

37.  The Continental shelf is followed by the
Continental Slope.
 The slope is much steeper than the shelf and
plunges to a depth of about 3.6 kilometres.
 The Continental slope forms the sides of the
continents. The width ranges from 20 to 100
kilometres.
 In many places, deep underwater canyons gash
the slope.
Continental slope
(…Contd)

38.  One of the most surprising findings of the early
oceanographers was that the deepest parts of
the oceans are not at the centers.
 They are quite close to the margins of continents,
particularly in the Pacific Ocean.
 The continental slope of the Pacific is very close
to the coastlines, in almost the all surrounding
countries of the Pacific.
Continental slope

39.  A lot of Submarine canyons are found cutting
across the shelf and slope.
 They are often extending from the mouths of the
terrestrial rivers.
 The valleys may be 12m deep. The maximum
depth may go up to 300m.
Submarine canyons
(…Contd)

40. The following are the notable submarine canyons of
the Pacific Ocean:
1. Bering Canyon
2. Monterey Canyon
3. Navarin Canyon
4. Pribilof Canyon
5. Scripps Canyon and
6. Zhemchug Canyon.
Submarine canyons

41.  The deep ocean floor begins at the seaward
edge of the continental slope and rise.
 Deep-sea peaks, valleys, and plains lie beyond
the continental margin.
 The thickness of Sediments, in the oceans,
averages about 450 metres.
 The sediment cover in the Pacific ocean basin
ranges from 300 to 600 metres.
Deep ocean floor
(…Contd)

42.  The deep-sea sediments can reveal much about the
earth’s history of the last 200 million years.
 They show the evidences for various processes,
including seafloor spreading, the history of ocean
life, the behaviour of Earth’s magnetic field, the
changes in the oceanic currents and paleoclimate.
 The ocean basins are transient features
over geologic time, changing shape and depth while
the process of plate tectonics occurs.
Deep ocean floor

43.  An abyssal plain is an underwater plain on the
deep ocean floor. It is usually found at depths
from 3,000 meters to 6,000 meters.
 The abyssal plains are among the flattest,
smoothest and least explored regions on Earth.
 The abyssal plains occupy a significant portion of
the deep ocean basin.
Abyssal plains/hills
(…Contd)

44.  The abyssal plains cover nearly 75% of the
Pacific ocean floors.
 They are formed by the deposition of fine
sediment carried by turbidity currents.
 These sediments have covered and smoothed
out the irregularities in the morphology of the
ocean floor.
(…Contd)
Abyssal plains/hills

45.  The flatness of these plains is due to the result of
the accumulation of a blanket of sediments, up to
5 kilometers in thickness.
 These overlie the basaltic rocks of the oceanic
crust.
 The thick sediment deposits extend up to a
distance of about 1,000 kilometres inside the sea
from the slope.
Abyssal plains/hills

46.  The Pacific is the oldest of the existing ocean
basins.
 Its oldest rocks have been dated at about 200
million years.
 The Pacific basin is referred to as the “Ring of
Fire” due to intense earthquake and volcanic
activity occurring near areas of tectonic plate
subduction.
Ring of Fire

47.  The Mid-Ocean Ridges form a chief feature of
the deep ocean basin.
 The ridges consist of a chain of mountains that
runs about 60,000 kilometres through the three
major oceans.
 Scientists discovered the mountain chain
independently in each ocean and gave it different
names, including Mid-Atlantic Ridge, East Pacific
Rise, and Mid-Indian Ridge. (…Contd)
Mid Ocean Ridges

48.  Most mountains of the Mid-Ocean Ridges stand
about 1,500 metres above the sea floor.
 Deep valleys cut across the ridges in many
places, producing a rugged, fractured surface.
 Frequent volcanic activity occurs along such
central valleys.
Mid Ocean Ridges

49.  The East Pacific Rise is a mid-ocean ridge.
 It extends from the Gulf of California to a point
west of the southern tip of South America.
 It rises to an elevation of 2,130 meters above the
ocean floor.
 Along the East Pacific Rise, molten rocky magma
upwells from Earth's mantle , adding crust to the
plates on each side of the rise.
The Pacific Rises

50.  An Ocean Trench is a long, deep depression in
the ocean floor. These trenches are one of the
most striking features of the Pacific floor.
 Deep-sea trenches generally lie seaward of and
parallel to the island arcs or mountain ranges of
the continental margins.
(…Contd)
Deep Ocean Trenches

51.  Trenches virtually encircle the rim of the Pacific
basin.
 The trenches have lengths of thousands of
kilometres, They are generally of hundreds of
kilometers in width.
 They extend up to 3 to 4 km deeper, as valleys,
within the surrounding ocean floor.
Deep Ocean Trenches

52. 1) Mariana Trench
2) Tonga Trench
3) Phillipine Trench
4) Kuril-Kamchatka Trench
5) Kermadec Trench
6) Izu-Ogasawara Trench
7) Japan Trench
8) Yap Trench
9) Peru-Chile Trench
10) Aleutian Trench
11) Middle America Trench
12) Puysegur Trench
13) Vityaz Trench and
14) Ryukyu Trench.
Trenches of the Pacific Ocean
The notable trenches of the Pacific Ocean are:

53.  A seamount is an underwater mountain, rising from
the ocean seafloor. It does not reach to the oceanic
water's surface or sea level. They do not form
islands.
 These are typically formed from extinct
volcanoes that rise abruptly and are usually found
rising from the seafloor to an elevation of 1,000 to
4,000 metres.
 The smaller submarine volcanoes are called sea
knolls. (…Contd)
Seamounts

54.  The Pacific Ocean contains several long seamount
chains.
 They are formed by hotspot volcanism. These
include the two major seamount chains as, the
Hawaiian – Emperor seamount chain and the
Louisville seamount chain.
 Bathymetric Profiles from the Pacific, have shown
that there are about 10,000 seamounts existing
with more than 1 Km elevation.
Seamounts

55.  The flat-topped seamounts are called as Guyots.
 They are named after Arnold Henri Guyot (1807-1884),
the Swiss-born American geologist and geographer.
 Guyots are isolated submarine volcanic mountains with
a flat summit of more than 200 metres below the sea
surface.
 The flat tops may have diameters greater than 10 km.
 Guyots are most abundant In the Pacific Ocean.
 Their summits lie 1,000 to 2,000 metres, below sea
level.
Guyots

56.  An iceberg is a large piece of frozen ice that
has broken off from a glacier or an ice
shelf and is floating freely in open water.
 Icebergs generally range from 1 to 75 metres
above sea level and weigh 100,000 to
200,000 metric tons.
Icebergs
(…Contd)

57.  The term "iceberg" most likely got originated
from the Dutch term "ijsberg", which means
ice mountain.
 There are very few such features in the
Pacific as they are mostly in the north and
pacific nearer to the poles.
Icebergs

58.  There are active volcanoes in every part of the world.
There are about 1,500 active volcanoes, many of
them are located in the Pacific Ocean.
 The Pacific rim's "Ring of Fire" is an arc around
the Pacific Ocean where there are 400 and more
volcanoes.
 The Ring of Fire is composed over 75% of the world's
active and dormant volcanoes. The ring is about
40,000km long.
Active volcanoes

59.  The Pacific contains about 25,000 islands.
Many of them are concentrated in the south
and west. It is more than the total number in
the rest of the world's oceans combined.
 The majority of these islands are found south
of the equator.
Islands or Island arcs
(…Contd)

60.  Most of the Pacific Islands lying south of the Tropic
of Cancer are collectively referred to as Oceania.
In the south-western corner of the Pacific lie the
islands of Melanesia, dominated by New Guinea.
 Other important island groups of Melanesia include
the Bismarck Archipelago, Fiji, New Caledonia, the
Solomon Islands and Vanuatu.
Islands or Island arcs

61.  Islands in the Pacific Ocean are of four basic types
as, continental islands, high islands, coral reefs, and
uplifted coral platforms.
 Continental islands lie outside the Andesite line and
include New Guinea, the islands of New Zealand,
and the Philippines. Some of these islands are
structurally associated with nearby continents.
Types of Islands
(…Contd)

62.  High islands are of volcanic in origin, and may contain
active volcanoes. Among these are Bougainville,
Hawaii, and the Solomon Islands.
 The third and fourth types of islands are both
originated due to coral-growth.
 Coral reefs are low-lying underwater structures that
have built up on the basaltic lava flows of the ocean's
surfaces. One of the most dramatic is the Great Barrier
Reef off the northeastern Australia.
Types of Islands

63. The distribution of sediments in the oceans is
controlled by five primary factors:
 Age of the underlying crust
 Tectonic history of the ocean crust
 Structural trends in basement
 Nature and location of sediment source, and
 Nature of the sedimentary processes
delivering sediments to the basins.
Sedimentation

64.  The volume of the Pacific Ocean is
approximately 622 million cubic km.
 Water temperatures in the Pacific vary from
freezing in the pole-ward areas to about 30 °C
(86 °F) near the equator.
 Salinity also varies with reference to latitudes.
(…Contd)
Water masses and Temperature

65.  The water near the equator is less salty than that
one found in the mid-latitudes because of
abundant equatorial precipitation throughout the
year.
 Because the vast majority of the world ocean's
volume, the mean temperature of seawater is
low.
(…Contd)
Water masses and Temperature

66.  About 75% of the ocean's volume has a
temperature from 0° – 5°C .
 The same percentage falls within a salinity range
between 34–35 ppt.
 The Surface temperatures can range from below
freezing point near the poles to 35°C in restricted
tropical seas, while the salinity can vary from 10 to
41 ppt.
 The western tropical Pacific has the warmest
surface waters.
Water masses and Temperature

67.  The salinity of sea water, denoted by the symbol
O/OO, is defined as the number of grams of
salts contained in 1000 grams of sea water.
 Sea water is about a 3.49% salt solution. The
more saline, the denser the seawater.
 As the range of salt concentration in the ocean
varies from about 3.2 to 3.8%, oceanographers
refer to salt content as 'salinity'.
Salinity
(…Contd)

68.  Three major factors influence salinity (salt
concentration) in Pacific Ocean waters. They are
precipitation, evaporation and winds.
 Around the equator, where there is large amounts
of rainfall, the surface water salinity rarely exceeds
34 parts per thousand.
 The lowest salinity in water occurs in the extreme
northern regions of the Pacific, near the Bering Sea.
Here, the salt concentrations are often less than 32
parts per thousand.
Salinity

69.  Ocean water gets more dense as temperature
goes down. So, the colder the water, the more
dense it is.
 Increasing salinity also increases the density of
sea water. The density of ocean water is rarely
measured directly.
 The measured density values are on the
average to ±4.3 × 10−6 g cm−3.
Density
(…Contd)

70.  The density of water in the Pacific were found to be
a) ±3.8 to ± 3.0 × 10−6 g cm−3 from 0 to 490m depth
zones,
b) 12.5 ±4.2 × 10−6g cm−3 from 490 to 1000 m depth
zones and
c) 17.6 ± 2.6 × 10−6g cm−3 from 1000 to 5834 m
depth zones. In the deep waters, the measured
values of density are equal to 6 × 10−6 g cm−3 .
Density

71.  The Climate of the Pacific is greatly influenced by
the following:
 planetary air pressure systems
 trade winds and westerly winds
 tropical cyclones (hurricanes & typhoons)
 continental influences and the
 monsoonal - a rainy season.
Climate of the Pacific

72.  The planetary air pressure systems and resultant
wind patterns exhibit remarkable uniformity in the
climate of the south and the east.
 The trade winds and westerly winds are well-
developed patterns, modified by seasonal
fluctuations.
 Tropical cyclones (hurricanes) may form south of
Mexico from June to October and affect Mexico
and Central America.
Effects on Climate
(…Contd)

73.  The continental influences cause climatic uniformity to
be much less pronounced in the eastern and western
regions at the same latitude in the North Pacific
Ocean.
 The western Pacific is monsoonal with a rainy
season occurring during the summer months, when
moisture-laden winds blow from the ocean over the
land.
 The tropical cyclones (typhoons) may strike southeast
and east Asia from May to December.
Effects on Climate

74.  The waters of the pacific ocean move constantly.
Two types of circulation create the currents in the ocean.
 They are:
(1) wind-driven circulation and
(2) thermohaline circulation.
 Wind-driven circulation results from the wind blowing on
the ocean surface. Wind-driven currents move in
enormous circular patterns called gyres.
Water circulation and Ocean Currents

75.  The surface circulation of the oceans is
intimately tied to the prevailing wind circulation
of the atmosphere.
 Major circulation of water in these gyres is
clockwise in the Northern Hemisphere and
counter-clockwise in the Southern Hemisphere.
Surface Circulation
(…Contd)

76.  The circulation of ocean waters is vitally
important in dispersing heat energy around the
globe.
 In general, heat flows toward the poles in the
surface currents, while the displaced cold water
flows toward the equator in deeper ocean
layers.
Surface Circulation

77.  Thermohaline circulation refers to the
deepwater circulation of the oceans.
 It is primarily caused by differences in density
between the waters of different regions.
Thermohaline Circulation

78.  There are two major wind systems driving the
waters of the Pacific Ocean. They are the
westerlies and the trade winds.
 The Westerlies lie about 40−50° latitude in both
the hemispheres.
 They are called as the “roaring forties” and the
trade winds come from the east which dominate
in the region between 20°N and 20°S.
Wind systems

79.  Huge whirls, formed by the major ocean currents, are
found roughly north and south of the equator.
The chief currents of the North Pacific, beginning at the
equator, are the North Equatorial Current, Kuroshio
(Japan Current), North Pacific Current, or Drift, and
California Current.
 The south equatorial current and the Antarctic
circumpolar current, both are belonging to the South
pacific currents.
Oceanic currents

80.  Scientists have discovered waves that rise up to
be taller than some sky scrapers.
 The ocean waves, which are also known as
internal waves, form at the boundary between two
layers of water with different densities in a deep
ocean trench in the South Pacific Ocean.
 The highest waves are found to be as much as
15 to 20 m.
Ocean waves

81.  The first appearance of life on the earth is thought to
have occurred in the oceans, in about 2 or 3 billion
years ago.
 Biological oceanography is an important aspect of all
oceans.
 The modern marine environment of oceanic waters, is
divided into two major realms as the benthic realm
and the pelagic realm.
 These are classified based upon the ecological
characteristics and marine life associated with them.
Ecological zones
(…Contd)

82.  The Pacific ocean has an incredible variety of living
things.
 These marine life ranges in size from microscopic
one-celled organisms to the blue whale, which may
measure up to 30 metres long.
 They are divided into three groups as the plankton,
nekton, and the benthos.
Ecological zones

83.  The benthic realm refers to the floor of the oceans,
extending from the high tide line to the greatest
ocean depths.
 The organisms that live in or on the bottom are called
benthos.
 The benthic realm is subdivided on the basis of depth
into the littoral zone, which extends from high tide to
a depth of about 200 m, and the deep-sea realm.
The Benthic Realm
(…Contd)

84.  The benthic life forms are both sessile (attached) and
motile (mobile). Some benthonic life forms live by
predation.
 Many others live on the organic matter from the water.
Some others scavenge the bottom for organic debris
that are available inside.
 Benthonic plants can live only in the euphotic zone,
the uppermost 100–200 m of the ocean, where
sunlight penetrates.
 Benthonic animals that live below the euphotic zone.
The Benthic Realm

85.  The pelagic realm consists of all of the ocean water
covering the benthic realm.
 It is divided horizontally into two zones as neritic
(fertile near-shore) province and the oceanic
province.
 Vertically it is divided into the euphotic, or photic,
zone and the aphotic (without sunlight) zone.
The Pelagic Realm
(…Contd)

86.  Drifting, free-floating organisms, called plankton,
and organisms with poor mobile ability populate
the euphotic zone. Most plankton are microscopic
or near-microscopic in size.
 Heterotrophic plankton (zooplankton) are also
floating animals and protozoans of the sea, rely on
the phytoplankton as food sources.
(…Contd)
The Pelagic Realm

87.  Foraminifera and radiolaria are the dominant
protozoan.
 Many juvenile forms of swimmers (such as
shrimp) or bottom dwellers (such as barnacles)
pass through a planktonic phase.
 Marine organisms capable of self-locomotion are
called nektonic life forms. Fish, squid, and
whales are examples of marine nekton.
The Pelagic Realm

88.  The ocean is home to countless numbers of plants
and animals.
 Most of the Ocean's plant life requires sunlight,
many ocean plants float on the surface of ocean
waters or live on the ocean floor in shallow water.
 These plants provide food, protection and habitats
for many marine animals. Some plants are also
sources of vitamins and minerals for people.
Marine fauna

89.  Fish are the most important animals of the nekton.
About 13,300 kinds of fish live in the ocean.
 Squids are free-swimming molluscs (animals with
soft, boneless bodies) that have 10 arms.
 Nektonic mammals include dugongs, manatees,
porpoises, and whales, all of which remain in the
ocean all their lives.
Marine Life in the Pacific Ocean
(…Contd)

90.  Other marine mammals, such as sea lions, sea
otters, seals, and walruses, spend time on land.
 The Pacific's greatest asset is its fish.
 The shoreline waters of the continents and the
more temperate islands yield herring, salmon,
sardines, snappers, swordfishes, and tuna, as
well as shellfish.
Marine Life in the Pacific Ocean

91.  The ocean is a complex environment that is home
to many types of plant species.
 Plants found in the ocean provide a basic source
of food and shelter for marine life.
 The kinds of plants found in the ocean are of two
basic types as those that have roots and those
that do not have any roots.
Marine flora
(…Contd)

92.  Most plants need sunlight, water and soil in order to
grow. Many plants also thrive in the ocean habitat.
The most famous plants are:
 Seaweed
 Seagrass
 Phytoplankton
 Kelp
 Red Algae
 Coralline Algae.
Marine flora

93.  The thickest deposits of sediment on Earth are
on the ocean floor.
 In the oceans, it piles up to 8 km in thickness.
 The thickest build up of sediments are found on
the continental rises and slopes.
Marine sediments
(…Contd)

94.  Ocean sediments are basically small insoluble
particles of rocks, soil, volcanoes, chemicals and
organic bodies.
 They are delivered into the ocean from lands via
rivers, streams and lakes.
 These particles are of different sizes and volumes,
and are commonly present on the shores of
oceans.
Marine sediments

95.  There are four major types of ocean sediments, which
are composed by different organic and inorganic
materials.
 These include
a) Hydrogenous Sediments,
b) Biogenous Sediments,
c) Lithogenous Sediments And
d) Cosmogenous Sediments.
Types of sediments in oceans

96.  Hydrogenous sediments are usually found near
the hydrothermal vents where metal ions are
released into the water.
 They combine with the silica and become a dark,
metal-rich sediment.
 Other forms of hydrogenous sediments are
manganese nodules, phosphates, carbonates and
evaporite salts and ammonia.
Hydrogenous Sediments
(…Contd)

97.  The hydrogenous sediments are the result of
chemical reactions between hydrogenous
minerals of the oceans and rivers, or are simply
created during the precipitation process (or
condensation process) of the ocean's water in
changing climatic conditions.
Hydrogenous Sediments

98.  The biogenous sediments are the hard and
insoluble remains of organic life on sea and land
(like bone particles).
 The Biogenous marine sediment is a kind of
pelagic marine sediment.
 It contains remnants of living organisms, mostly
plankton.
Biogenous Sediments
(…Contd)

99.  The plankton that forms this sediment comes from
species that have shells made of calcite and opal.
For phytoplankton, the plant-like photosynthesizers,
coccoliths have calcite shells and diatoms have
siliceous or opal shells.
 Zooplankton, the animal element, produce
foraminifera that have calcite shells and radiolaria
composed of siliceous or opal shells.
Biogenous Sediments

100.  The lithogenous sediments are tiny particles from
rocks, volcanic eruptions, metal ores and various
other natural elements.
 Feldspar grains are found in lithogenous marine
sediment as well as lithogenous clay.
 Lithogenous clay is termed pelagic clay if more than
70 percent of it has lithogenous sediment in its dry
mass.
Lithogenous Sediments
(…Contd)

101.  The Ocean floors in the deepest parts of the
Pacific Ocean are predominately composed of
lithogenous sediment. In the central ocean basins,
the largest component of lithogenous sediment is
clay.
 The Cosmogenous sediments are tiny meteorites
and specks, which are extraterrestrial in nature.
Lithogenous Sediments
Cosmogenous Sediments

102.  The exploitation of the Pacific's mineral wealth is
hampered by the ocean's great depths.
 In shallow waters of the continental shelves off
the coasts of Australia and New Zealand,
petroleum and natural gas are extracted.
Economic mineral resources
(…Contd)

103.  Pearls are harvested along the coasts of Australia,
Japan, Papua New Guinea, Nicaragua, Panama,
and the Philippines.
 The mineral wealth of the ocean extends to the
deep-sea floor.
 Deposits near undersea hot springs contain
copper, iron, and zinc.
Economic mineral resources

104.  The shallow continental shelves have been exploited as
a source of sands and gravels. In addition, extensive
deposits of petroleum-bearing sands have been
exploited in offshore areas, particularly along the Gulf
and California coasts of the United States and in the
Persian Gulf.
 On the deep ocean floor manganese nodules, formed
by the precipitation of manganese oxides and other
metallic salts around a nucleus of rock or shell,
represent a potentially rich and extensive resource.
Mineral resources of the Pacific Ocean
(…Contd)

105.  Ocean water is processed to extract
commercially valuable minerals such as salt,
bromine, and magnesium.
 Although nearly 60 valuable chemical elements
are found to have been dissolved in ocean water.
 Most of them are in dilute concentrations. Due to
this, their commercial extraction is not profitable.
Mineral resources of the Pacific Ocean

106.  The ocean has been a highway for trade since people
built the first ships thousands of years ago.
 Today, transportation--especially of heavy and bulky
products--remains an important use of the ocean.
 Most of the transpacific sea-lanes pass through the
Hawaiian Islands.
 Since the 1950s, many of the South Pacific islands
have become world famous tourist centers.
Commerce and shipping

107.  Strategically important access waterways along
the Pacific include the
 La Perouse,
 Tsugaru,
 Tsushima,
 Taiwan,
 Singapore, and
 Torres Straits.
Waterways along the Pacific

108.  Bangkok (Thailand),
 Hong Kong (China),
 Kao-hsiung (Taiwan),
 Los Angeles (US),
 Manila (Philippines),
 Pusan (South Korea),
 San Francisco (USA),
 Seattle (USA),
 Shanghai (China),
 Singapore,
 Sydney (Australia),
 Vladivostok (Russia),
 Wellington (NZ), and
 Yokohama (Japan).
Ports and terminals
Ports and terminals of the Pacific Ocean are:

109.  Marine pollution is a generic term for the harmful
entry into the ocean of chemicals or particles.
 The Pacific is no exception to all kind of pollutants
entering into the sea.
 Oil is a major source of ocean pollution.
Marine pollution
Problems of the Pacific Ocean

110.  Most oil pollution enters the ocean from oil spills on
land or in rivers used to transport petroleum.
 The world's largest accidental oil spill occurred in June
1979, when an oil well blew out off the east coast of
Mexico and spilled about 490 million litres of oil.
(…Contd)
Problems of the Pacific Ocean

111.  Ocean dumping is yet another problem of the Pacific.
 The deliberate dumping of waste products into it is
another major source of ocean pollution. Such products
include industrial waste and sewage.
 Industries dump chemicals, animal and plant matter,
and other pollutants.
 Throughout the history, humans have been directly or
indirectly influenced and benefitted by the oceans.
Ocean Dumping

112.  The Pacific is surrounded by a zone of violent volcanic
and earthquake activity. The pacific is also subjected
to frequent tropical cyclones (typhoons) in southeast.
 Tropical cyclones (hurricanes) may form south of
Mexico and strike Central America and Mexico from
June to October.
 Cyclical El Nino/La Nina phenomenon occurs in the
equatorial Pacific, influencing weather in the Western
Hemisphere and the western Pacific.
Hazards
(…Contd)

113.  Ships are subjected to superstructure icing in
extreme north from October to May.
 Persistent fog in the northern Pacific can be a
maritime hazard from June to December.
 Most tsunamis strike land areas in or bordering the
Pacific Ocean.
 Fortunately, scientists can predict how fast a
tsunami is moving and are able to warn people in its
path.
Hazards

114. Thank You