10 Facts about the Ocean

On World Oceans Day

08 June 2021/Kiel. Today is World Oceans Day. The ocean is the largest habitat on our planet, yet still largely unexplored. It is essential for providing vital oxygen.But our oceans are under increasing pressure: human activities are destroying habitats, polluting the oceans, and greenhouse gas emissions are causing the ocean to acidify and oxygen levels to decline. In addition, sea levels continue to rise.

Knowing more about our ocean in order to protect it and use it sustainably is one of the core goals that is also being pursued at GEOMAR Helmholtz Centre for Ocean Research Kiel. For World Oceans Day, we have therefore compiled 10 facts about our ocean in order to make the dimension and importance of our oceans clear in a simple and striking way.

To the 10 Ocean Facts

Ocean Facts - World Oceans Day 2021
Did you know that the entire ocean covers 70 percent of the surface of our planet, and the deep sea 50 percent? The area of the Pacific Ocean alone is larger than the entire land area of the Earth.
Did you know that the ocean is on average depth of 3,800 metres? The deepest point of the ocean is the Challenger Deep in the Mariana Trench at about 11,000 metres.
Did you know that high-resolution multibeam echo sounder data are only available for just under 20 percent of the entire seafloor? Echo sounders are the only method to map the large areas of the seafloor directly.
Did you know that the ocean contains roughly one million different species of plants and animals, up to two thirds of which have not been named and described yet?
Did you know that phytoplankton provides half of the oxygen we breathe? Without the ocean, the prospects for human life on Earth would be greatly diminished.
Did you know that the ocean is delaying the effects of climate change by absorbing more than 90 percent of the extra heat energy so far?
Did you know that the ocean has absorbed about 30 percent of the carbon dioxide released into the atmosphere by human activities since the beginning of industrialisation?
Did you know that the pH value in the ocean has decreased from 8.2 to 8.1 due to the previous uptake of CO2? This seems to be a small difference but it already corresponds to an increase in acidity of 30 percent. By the end of the century, the pH value could probably drop by another 0.3 to 0.4 units, making seawater 100 to 150 percent more acidic. This would become in particluar an increasing problem for calcifying organisms, even leading to the disappearance of entire species.
Did you know that the ocean has lost more than two percent of its oxygen globally in the past 50 years? The main cause is global warming. The warmer the seawater, the less O2 can be bound in the water. In some areas of the ocean, oxygen levels have decreased by up to 40 percent. The amount of water in the ocean that lacks any oxygen has grown by a factor of four in the past 50 years.
Did you know that the average global sea level has already risen by about 15 centimetres in the 20th century? According to current projections, a global mean rise of 50 to 100 centimetres must be expected by the end of this century. Even without any greenhouse gas emissions, the sea level would rise for several centuries due to the inertia of the climate system.