How many people believe that wherever the beach ends, that’s where the open ocean begins? When I was younger, I believed that too. While the continental shelf is part of the ocean, it is different from the open ocean.
The open ocean is a massive body of water that goes down thousands upon thousands of feet. Obviously, there’s a bit more to it, and the open ocean is divided into zones that I’ll go over at some point, but at the moment, let’s just call the open ocean a massive body of water.
The continental shelf, by contrast, is a continuation of the continent that exists just under the surface of the ocean.
During the last ice age, many of these shelves were above the water and acted as extra land for species to use. In fact, it is believed that the Bering Strait, which allowed humans to cross from Eurasia to North America, was one of these continental shelves. These areas were exposed to the open air because of the decrease in sea level due to colder temperatures. However, after the ice age, a lot of the glacial ice melted and the sea level rose again, covering up the continental shelves.
Since the last ice age, these areas have been very important to the ocean and to those who live on the coasts of the continents, man and beast alike.
Continental shelves have shallow seas, with average depths between 300‒600ft (100‒200m) that are fed by rivers from the mainland. These rivers carry all sorts of things to the ocean—fresh water, sediment from erosion, and vital nutrients from land run-off—all of which mix together to make for a very productive environment. Continental shelves support all sorts of environments for marine life, like coral reefs, kelp forests, sea grass beds, etc.
The shallow, nutrient-rich water allows algae and other plant life to get enough sunlight and other components for photosynthesis, and from there the environments create themselves. Plants bring in plant-eaters, and the herbivores bring in predators. These areas are also important because their environments provide space for many of the oceans’ inhabitants, such as sharks, dolphins, and various fish, to breed and have their young—so these places act as nursery grounds!
The continental shelves are also important to you because that’s where a lot of the fish you eat comes from. There are all sorts of fish farms and commercial fishing operations that occur off the coast, providing food for the continent’s population, and even to other continents as well, depending on the species being caught or raised.
Even before modern times these areas have provided major support to coastal human populations because of the amount of fish and other resources found there. Now, these places also provide income from tourism because inland-dwelling people want to experience the beauty of the ocean for themselves.
Thank you for letting me share with you what continental shelves are and why they’re so important to us. They harbor so much life, and they provide benefits for not only the ocean but for many of us on land. They contain coral reefs, kelp forests, and various sea bed environments that are so important to the ocean and its inhabitants and, by extension, to all of us!
Sources and other cool links to help you learn more:
Ocean: The Definitive Visual Guide made by the American Museum of Natural History
Ocean: A Visual Encyclopedia made by the Smithsonian
*note on the links: they have more of a geological look into the continental shelves like how they’re formed, their layout, etc.*