Blue Planet: Coasts
Aerial view of an island in the Great Barrier Reef, Australia.
Some of the most productive and biologically rich areas on Earth
The coastal zone makes up only 10% of the ocean environment, but is home to over 90% of all marine species. For example, of the 13,200 known species of marine fish, almost 80% are coastal.
The coastal zone has the most nutrients of all marine environments. Sunlight can penetrate the shallow waters above continental shelves (land that slopes gently down from the coastline of most continents to a depth of around 200m) meaning that plants can grow, while the sea floor provides an anchor for many organisms. As a result, a number of extremely productive and complex coastal ecosystems have evolved.
Not only do these ecosystems support a huge variety of life, many also serve as nurseries for much of the biodiversity of the entire oceanic system. These ecosystems also help protect coastal land from erosion due to storm surges and other large waves, such as tsunamis.
The coast also has a huge influence on people. According to the UN, around 3.6 billion people, or 60% of the world’s population, live within 60km of the coast. And 80% of all tourism takes place in coastal areas. Most of the goods we extract from the ocean - from fish to oil and gas - come from coastal regions. Coastal ecosystems also provide a range of services that benefit people around the world.
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