Ocean is a vast, blue body of salt water that covers 70% of Earth’s surface. It is an important part of the Earth’s hydrosphere, and as a heat reservoir, it influences climate and weather patterns.
The ocean also provides critical resources that sustain life on our planet. Its fisheries supply many people with food, and its ecosystems provide raw materials for products we use every day such as medicines, fertilizers, and cosmetics.
In addition, the sea has tremendous natural beauty that attracts millions of tourists each year, generating substantial economic activity. However, oceans are also under threat. Their health is being impacted by pollution, overfishing, climate change and other human activities.
Scientists have learned a lot about the outer parts of the ocean, but they still have much to discover at the depths. For example, the bottom of the ocean is not flat — it’s full of ridges and canyons that can be hundreds of miles long. The ocean’s residence time (the amount of time it takes for an element to be removed from the system by biological cycling) varies depending on the supply from processes such as rock weathering and rivers, and removal by evaporation and sedimentation.
The Ocean is the largest ecosystem on the planet, and its water cycle has a profound impact on life on Earth. It provides more than half the oxygen in our atmosphere, and the water that evaporates from the Ocean is blown by the wind over land, increasing humidity and creating rain. This rain is then absorbed by vegetation and animals, including humans, and makes its way back to the Ocean via streams and rivers.
A healthy Ocean regulates climate, reduces hurricane intensity, and helps reduce global warming. It also provides at least one fifth of the animal protein that we eat, and it is a sink for nearly 90% of carbon dioxide emissions.
National Geographic is dedicated to exploring the world’s oceans and restoring their health. We do this by inspiring people to care and act, reducing the impact of fishing, and promoting the creation of marine protected areas.
A healthy Ocean is a vitally important component of the world’s ecosystems, providing protein and oxygen for billions of people. Learn more about the importance of the Ocean by using these free, kid-friendly resources: