The Ocean – Home to a Spectacular Diversity of Marine Organisms

Ocean is the largest ecosystem on Earth and home to a spectacular diversity of marine organisms. It produces, through photosynthesis performed by microscopic marine plants, 50-80% of the oxygen we breathe. It regulates global climate by transferring heat from the Equator to the Poles and back again. It stores enormous amounts of carbon and provides food, minerals, and raw materials for human life. It is a source of energy and provides jobs to millions of people worldwide through fisheries, shipping, tourism, leisure activities and research.

The Ocean also provides a range of essential health benefits. For example, people living near the sea are less likely to suffer from depression and have better skin. The sea’s natural medicinal properties are well known and used in medicine to treat everything from tuberculosis, stomach ulcers, and asthma. And, for many people, simply looking at the Ocean brings a sense of wellbeing.

Scientists have identified a huge range of economic benefits from the ocean, including fisheries, offshore oil drilling and mining, and coastal and marine-based tourism. Ocean transport links economies around the globe and is an important driver of international trade.

The world’s Oceans have a combined economic value of more than USD $2.5 trillion per year, equivalent to the 7th largest economy in the world. This contribution to human welfare comes from a variety of marketed and non-marketed ‘ocean ecosystem services’, including water, nutrient, mineral and renewable energy resources as well as biodiversity, climate regulation, storm protection, and waste recycling.

On a daily basis, the Ocean is the primary source of protein for 3 billion people, through fish and other seafood. It is also a major source of calcium, iodine, potassium and magnesium. Our bodies need these minerals, and our plants and animals need the oxygen that phytoplankton – tiny marine plants – produces through photosynthesis. The ocean provides all this, through a complex water cycle that is driven by the Ocean itself.

Almost 70% of the planet’s surface is covered by Ocean, and it covers 97% of all water on the Earth. The ocean is one global system, but it is conventionally divided into four regions: Pacific, Atlantic, Indian and Arctic. Oceans form as a result of the movement of Earth’s tectonic plates. As the plates move, molten rock rises through cracks in the Earth’s crust and forms new seafloor. This process is called seafloor spreading, and it has been occurring for millions of years.

Seas are salty because they contain dissolved minerals and salts that have been washed off the land by rain. As the rain falls, it washes away these minerals and carries them into rivers and then into the Ocean. Over time, this makes the Ocean saltier and deeper. The water is also salty because of the huge amount of water that evaporates and sinks, creating a great reservoir of salty water.

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