The oceans cover about 3/4 of the earth’s surface which makes it an important
component of life in our planet. Underneath 10,000 feet of generally cold and
salty water are geographic features similar to what you see on dry land - tall
mountain ranges, extensive planes, volcanoes, valleys and hills. On beaches,
waves and tides are the most commonly observed features of the oceans and
represents the rhythmic up and down movement of the water level due to wind
forcing and the gravitational pull of the moon and sun respectively.
Large volumes of water are continously being transported from the warm
equatorial areas to the cold polar regions which accounts for our planet’s mild
climate. These currents are strongest and well defined on the western margins
of the oceans. For example, the Gulf Stream Current off the eastern United
States transports twenty five times more water than all rivers of the world
combined.
Life abounds in the oceans fueled by one-celled plants called phytoplankton.
As a result, different varieties of fish, whales, sharks, lobsters, sea cucumbers,
coral reefs, octopus, conch, etc. are found in the coastal regions where sunlight
and nutrients are available. In the open oceans, highly migratory species of fish
like tuna, salmon and eel scour the oceans in search of food and spawning
grounds.
Except for the cool bioluminiscent glow of deepwater organisms, the ocean is
virtually a dark abyss at depths greater than 200 meters. In the past, scientists
postulated that no life exists in the deep recesses of the oceans. However, the
recent discovery of flourishing animal communities around deep sea vents have
sparked renewed interests in the exploration of life in the deep among
oceanographers and marine biologists. Aided by manned submersibles and
guided robots, much is being discovered in this last frontier.
