Scientists estimate that 50-80 per cent of the oxygen production on Earth comes from the ocean. The majority of this production is from oceanic plankton — drifting plants, algae, and some bacteria that can photosynthesize.

Stretching for 1,429 miles over an area of approximately 133,000 square miles , the Great Barrier Reef is the largest coral reef system in the world.

No plants live at these depths because there is no light. Some animals do though. They live in total darkness, at extreme pressure, with relatively low oxygen levels, and at temperatures of less than 4 degrees. 

If Mount Everest was dropped into the trench at the deepest point of the Mariana Trench, its peak would still be 1.6 km underwater.

Some 33,000 marine species, mainly animals, are recorded from Australian waters.  About 17,000 others have been collected but not catalogued. It is estimated that only 10-20% of Australian marine organisms may have been sampled – so there may be as many as 250,000–500,000 Australian marine species. 

The part of the ocean farthest from land lies in the South Pacific and is known as Point Nemo or ‘The Pole of Inaccessibility’. Point Nemo isn’t an actual ‘point’ as (obviously) there’s no land there — it’s simply a spot in the ocean that happens to be 2,688 kilometres from the nearest land. The name doesn’t come from the film Finding Nemo. It actually comes from Jules Verne’s Captain Nemo of Twenty Thousand Leagues under the Sea.