The document discusses the formation of oceans on Earth. As the molten surface cooled over time, volcanic gases formed an atmosphere and water condensed from the atmosphere to form oceans. Life then emerged in the oceans. The three major oceans - Pacific, Atlantic, and Indian - formed as the supercontinent Pangaea broke apart. These oceans have varying depths, islands, currents, and features such as coral reefs and mid-ocean ridges. The document also describes how salinity and temperature vary in ocean waters due to factors like evaporation, rainfall, and ocean currents.

1. ocean and man

2. • At the time of birth the earth was a
molten sphere, but with the passage of
time its surface is cooled, but inside it
was boiling one. Due to volcanic
eruption several gases came out and
became cover of the earth
• Then due to further cooling the water
condensed into rain, as a result water
bodies were formed, thus ocean formed

3. • Life emerged on the earth gradually,
and now all the creatures
depending on the ocean

4. ocean
• 71% of earth surface is
surrounded by water
• The inter connected body of
water on the earth comprising
all oceans forms world ocean

6. activity
•Examine the globe
and find out the
major oceans

7. Bay and gulf
• Bay is wide segment of ocean
extending into the sea
• E.g. bay of Bengal
• Narrow portion of n ocean
extending into land
• E.g. gulf of Cambeth

10. • It is believed that the land we see
today is formed as one land mass
called Pangaea, it was
surrounded by a mega ocean
called Panthalassa
• When this land mass separated
and drifted away and formed
different forms of oceans

11. Major ocean
Ocean Area Average
depth
Deepest
trench
The pacific 165.2 lakh
sq km
4270m Challenger
11o33 m
The
Atlantic
82.4 “ 3700m Puerto rico
8618 m
The Indian
ocean
73.4 “ 3960 m Wharton
trench

12. • Pacific ocean has the greatest number of
islands about 20000 numbers
• Salient features of Atlantic ocean is Mid
Atlantic ridge which is 14000 km in
length, the island found in this region are
volcanic origin
• The number of island in Indian ocean is
comparatively small
• Madagascar and Srilanka are examples
for continental island

14. • Andaman- Nicobar islands are the
part of chain of islands stretching
from Myanmar to Australia
• Coral islands are also found in Indian
ocean, it is formed by the accretion
of dead remain called polyps, it
found in coral reefs, Lakshadweep
and Maldives in Indian ocean are
examples

16. Salinity and temperature in ocean
water
• Salinity in the ocean is the amount of
salt present in the sea water
• It usually expressed in grams per 1000
grams
• Average salinity of the ocean water is
35/1000 grams
• Main reason for salinity is sodium
chloride (common salt)

17. Other salts
• Magnesium chloride
• Magnesium sulphate
• Calcium sulphate
• Potassium sulphate
• Calcium carbonate
• Magnesium bromide

18. Factors affecting salinity
• When evaporation increases salinity
increases
• Salinity will be low in the region of heavy
rainfall
• Water reaches to ocean from the melting ice
causes salinity decline
• Salinity is less near the estuaries
• In the areas of cold and warm current meets
salinity is comparatively low

19. • Temperature of the ocean water is
ranges between 2-33 degree Celsius
• Latitude salinity presents of land
gulf are affects the distribution of
temperature
• When the latitude increases
temperature decreases

20. thanks