ocean and man

• 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

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

ocean

• 71% of earth surface is surrounded by water• The inter connected body of

water on the earth comprising all oceans forms world ocean

activity

•Examine the globe and find out the major oceans

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

• 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

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

• 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

• 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

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)

Other salts

• Magnesium chloride• Magnesium sulphate• Calcium sulphate• Potassium sulphate• Calcium carbonate• Magnesium bromide

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

• 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

thanks