Ocean is a vast area of water that covers the Earth, separating continents from each other. Its waters are full of life, supporting many diverse species and regulating the global climate. Oceans are also a source of energy and raw materials, including the oxygen we breathe and food we eat. The vastness of the sea can be intimidating, but it is also a place of adventure. The ocean has provided inspiration for many of mankind’s greatest achievements. Its beauty and mysteries have captivated people for millennia, inspiring artists, writers, and even Hollywood blockbusters such as the 1995 film Waterworld.
The word ocean comes from the Greek god Oceanus, who was believed by ancient Greeks and Romans to be a huge river encircling the world. It is believed that a sizable amount of water would have been present in the material from which Earth was formed, and it may have escaped from the planet’s gravity more easily than terrestrial matter.
Whether from its warm, sunny beaches or its deep and nutrient-rich waters, the ocean offers an almost endless array of opportunities for marine life. Coral reefs provide shelter and nourishment for many animals, while schools of fish teem with activity. The salty water is a natural magnet for humans, too, who swim, surf, and scuba dive in it for recreation, work, and research.
Scientists study the world’s oceans to learn more about their role in the Earth system and to better understand our own relationship with them. They are the Earth’s largest ecosystem, providing a source of food, minerals, and other resources for living things, as well as regulating the global climate.
The global ocean is divided into several zones based on physical and biological conditions. The photic zone is the upper layer of the ocean where light is strong enough for photosynthesis to occur. Plants and microscopic algae in the photic zone produce half of the oxygen on Earth’s surface. The twilight zone, below 200 meters, is dark and only the faintest glimmer of light exists beyond 1,000 meters (the midnight zone).
Ocean currents, driven by solar heat and the rotation of the Earth, transport warm surface water to the poles and cooler deep water toward the Equator. They carry rich supplies of nutrients, which come from plankton and the remains of other organisms that drift down from the surface.
Water pressure is a significant challenge for any attempt to build an underwater habitat. Unless technology advances dramatically, sci-fi-like images of futuristic communities living on the ocean floor will remain just that – a fantasy.
Human activities affect ocean life and marine habitats in a variety of ways, from marine pollution and overfishing to the accelerated rate of ocean acidification. Those who seek to sustain the health of the ocean should focus on increasing funding for ocean science, intensifying conservation efforts, and urgently turning the tide on climate change. The future of our shared planet depends on it.