The Waters of the Earth

Junhel C. Dalanon, DMD, MATSNSCLC – Minglanilla

Minglanilla, Cebu, Philippines 6046

Introduction

• Hydrosphere – all the water on the surface of the earth

• ¾ of the earth is covered with water• Water is second most abundant substance

next to air• Same amount of water now as it had millions

of years ago

Oceans of the World

• Oceanography – study of ocean currents, tides, wave formation, energy exchange between oceans and atmospheres

• Different Oceans:1. Pacific2. Atlantic3. Indian4. Arctic5. Antarctic

Pacific Ocean

• Biggest• Deepest• Covers 3/8 of the total area of the global

ocean• 4144 meters Average Depth

Atlantic Ocean

• Second largest• ¼ of total area of global ocean• 3846 meters Average Depth

Indian Ocean

• Third largest• 1/8 of total area

Arctic Ocean

• Around the North Pole• 1/13 of the area• Almost totally covered with ice• 2.95 meters deep

Antarctic Ocean

• Covers the Antarctic continent• Smallest ocean• South Pole

Resources of the Ocean

• Desalination – salts & chemicals are removed from seawater so it can be used for drinking, in industry, and agriculture

• Food• Minerals• Salts• Fossil Fuels – oil & petroleum• Marine Animals – fish, coral, plankton• Microscopic Plants – Algae & Phytoplankton

Ocean Basin

• Basalt – First layer; (igneous rock)forms mostly the ocean basin

• Granite – second layer underneath basalt• Depth varies from one place to another• Continental Shelf – shallow edge of a continent• Continental Slope – drops abruptly from the

edge of the continental shelf; sides of the ocean basin; landslides often occur here

Ocean FloorFarther to the ocean from the shoreAffected by the process of volcanism & sedimentationRidges – mountain chainsSeamounts – 300 meters above the sea floor; volcanoes

under the seaTrenches – Deep gashes on the ocean floor; deepest parts

of the oceanMarianas Trench – Marianas Islands near Guam 12, 066

meters deepMindanao Deep – 11, 880 meters deepOoze – made of mud; first 500 meters of the ocean floor

Sea Floor Spreading

• Caused by the formation of new crusts at oceanic rises

• Oceans have increased in depth at the rate of 1 meter per million years

Salt Water & Fresh Water

The salts dissolved in the sea account for the salinity of ocean water

Salinity - 3.2% or 3.5 parts of salt for every 100 parts of water

Common salts in sea water:1. Sodium Chloride2. Magnesium Chloride3. Potassium Chloride4. Calcium Sulfate5. Magnesium Sulfate

Salinity of Seawater

• What causes it to vary?• Rain Water• Melted Glacier• Crater from Rivers