What Would Our Earth Look Like Without Oceans?

Feb 20, 2020 By Ritali J, Writer
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James O'Donoghue, a planetary scientist from the Japan Aerospace Exploration Agency, recently remade a 2008 animation from NASA, revealing what the world would look like if the oceans were drained.

The animation was recreated at a higher resolution and a tracker was included to identify how much water was being drained. Let's look at the video first and some of the things that we learned.

 

Topographical Features

In the animation, we witness how, after only a few hundred feet of water are drained, undersea land immediately begins to appear on the edges of continents.

These formations, known as continental shelves, are patches of land which tend to lie much higher than the rest of the ocean floor. These act as transition zones between dry continental land and the gaping depths and constitute about eight percent of the region covered by oceans. Almost all continental shelves are visible at about 460 feet below sea level, except for the Arctic and Antarctic shelves, which are hidden deeper.

At 6,500 to 9,800 feet below water, Earth’s longest mountain chain rises, expanding across 37,000 miles of the planet, with the ocean covering about 90% of it. This mid-ocean ridge forms at the edges of divergent tectonic plates (separating plates) – as the plates move away from each other, molten rock and magma rise to fill in the gaps, creating new oceanic crust that cools to form these volcanic mountain formations underwater.

Most of the water disappears when the oceans are drained by 20,000 feet, though an additional 16,000 feet must be drained to remove water from steep valleys located in the deepest portions of the ocean, known as ocean trenches. These trenches form at converging tectonic plate boundaries (when plates move towards one another). During the process of subduction, the colliding plates cause the lighter crust to push the older, denser plate beneath it into the mantle. This forces a V-shaped bend into the seafloor’s outer crust. The deepest ocean trench, the Marianas Trench (located near the Philippines), is also the deepest spot on Earth.

Discoveries About Evolution

Continental ShelfThe animation not only reveals extensive information about the ocean’s hidden wonders, but also possible discoveries regarding underwater life. For example, the mid-ocean ridge systems have rich biological ecosystems, as heat from magma allows water and minerals to circulate at the seafloor level. The flow of heat and chemicals enables the development of life that depends on chemical activation for energy, not sunlight.

The animation also explains more about the ancient history of human evolution and migration. Continental shelves were exposed thousands of years ago during the Ice Age and acted as land bridges that early humans used to migrate between continents into new frontiers. Experts believe the original Americans arrived 16,000 years ago by crossing a land bridge connecting Siberia and Alaska.

This fascinating animation sheds light on a little-known part of our world and helps us to better understand our planet and evolution.

Sources: NASA, ScienceAlert, Forbes, Treehugger, mbari.org, whoi.edu