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Deep Sea Dive: Lakes in an Ocean

2 minutes

(Describer) Under a round logo of a wave, title: Ocean Today.

(female narrator) We know the earth isn't flat in any sense. We see mountains, valleys, hills, and holes. And the seafloor is just as diverse a landscape. But on certain places on the seafloor, like in the Gulf of Mexico, there are even underwater lakes and rivers. How is that possible? Lakes and rivers form when seawater seeps up through thick layers of salt, present beneath the seafloor. As the water rises, it dissolves the salt layer, making it collapse and form depressions. The dissolved salt makes the water denser, and because it is denser, it will settle into the depressions, forming a river or lake. These underwater lakes and rivers can be a few feet across or a few miles long. They're very similar to lakes and rivers on land, with shorelines, surfaces, even waves. There are creatures that enjoy hanging out there, like underwater beach bums. Huge fields of muscles grow near the edges of some lakes, but they're not exactly sunning themselves. This far beneath the ocean surface, sunlight is extremely hard to come by. As we know, sunlight plays an extremely important part in the land's food chain, but this far down, organisms like these muscles have adaptations that allow them to get their nutrients from bacteria that can convert methane and other chemicals in the salty water into energy. We've come far in our understanding of the ocean, but most places are still unexplored, and many questions are unanswered.

(Describer) Titles: Narrator: Caroline Miller. OceanToday.noaa.gov. Logos are shown for the Smithsonian and NOAA. Accessibility provided by the US Department of Education.

Accessibility provided by the U.S. Department of Education.

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The seafloor has a diverse landscape, which includes underwater lakes and rivers. How is that possible? Well, these lakes and rivers form when seawater seeps up through thick layers of salt, which are present beneath the seafloor. As the water seeps up, it dissolves the salt layer, causing it to collapse and form depressions. The dissolved salt makes the water denser, and because it is denser than the water around it, it will settle into the depressions, forming a river or lake. Part of the "Deep Sea Dive" series.

Media Details

Runtime: 2 minutes

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