· Life began in the seas 3.1 billion – 3.4 billion years ago. Land dwellers only appeared 400 million years ago.

· An estimated 80% of all life on earth is found under the ocean surface and the oceans contain 99% of the living space on the planet. Less than 10% of that space has been explored by humans.

· A deep estuary of an ocean can produce 150-155grams of carbon per square meter, per year. This is the same as a similar area of rain forest, planted crops or intensive agriculture.

· The ocean appears to be blue because the sunlight is reflected off the surface of the water, reflecting the colour of the sky. In deep water, much of the sunlight is scattered by the oxygen in the water and this scatters more of the blue light. There are some oddly coloured seas, such as The Red Sea, which often looks red because of red algae that live in the sea. The Black Sea looks almost black because it has a high concentration of hydrogen sulfide (which appears black).

· The sea level has risen by an average of 10-25cm over the past 100 years. Sea levels will continue rising even if the climate becomes stabilized because oceans react slowly to change. 10,000 years ago, the ocean level was about 110m lower than it is now. If all the world’s ice melted, the oceans would rise 66m.

· The colder it becomes, the denser sea water becomes. The average temperature of all ocean water is around 3.5 degrees centigrade.

· Antarctica has as much ice as the Atlantic Ocean has water.

· The Arctic produces 10,000-50,000 icebergs annually.

· The average depth of the oceans is 3,792 m.

· 90% of all volcanic activity occurs in oceans.

· The speed of sound in water is 1,435m/sec, nearly five times faster than the speed of sound in air.

· The pressure exerted at the deepest point in an ocean is more than 11,318 tons per square metre.

· The lowest point on earth, called Challenger Deep, is 11,034 metres deep. It is located in the Marianas Trench in the western Pacific. If you placed Mt. Everest at the bottom of this trench, there would still be more than a mile of water above it.

· The average depth of the Atlantic Ocean is 3,926 m. The greatest depth is 8,381 m., in the Puerto Rico Trench.

· The Earth has 1,386,000,000 km3 of water but only 2.5% of that is fresh water.

· Average consumption of water in the USA is between 250-300 litres per day. This water is used for drinking, cooking, bathing, watering gardens, etc. The average person in the Netherlands uses 104 litres per day for the same tasks.

· The average person in Gambia uses only 4.5 litres of water per day.

· The record for the deepest free dive is held by Jacques Mayol. His dive, to a depth of 86 metres, was performed without any breathing equipment.

· The largest single feature on earth is a mountain range, formed from the ocean ridges. It is almost 40,000 miles (64,000 km) long and winds through all the oceans.

· Mauna Kea, a mountain in Hawaii, rises 33,474 feet (10,203m) from its base on the ocean floor. Only 13,680 feet (4,170m) of this is above sea level.

· The ocean is salty because river water collects mineral salts from the rocks and soil of the river beds, then flows into the oceans and seas. Evaporation occurs in the oceans and seas but of course, the salt remains, dissolved in the water. Thus, the water gets saltier as time passes. How salty a sea or ocean is, is variable. The saltiest water is in the Red Sea and in the Persian Gulf, due to high levels of evaporation and less incoming fresh water. The least salty seas are in the Polar Regions, where melting ice and frequent rain dilute the salinity of the water.

· When you dive down deeper and deeper into water, the more gallons of water will lie between you and the surface. The greater the weight of the water above you, the greater the pressure on your body. This pressure is called hydrostatic pressure.