Slide 1 of 15
A Vast UnknownAbout 70 percent of the Earth's surface is covered with water, yet the oceans largely remain a mystery for scientists.
More is known about the moon's surface than the depths of the ocean. In fact, 12 people have stepped foot on the moon, but only three have been to the Mariana Trench — the deepest part of the ocean, at roughly 7 miles (11 kilometers) deep.
In celebration of World Oceans Day (June 8), here are a few of the most bizarre discoveries from the planet's oceans.
Mysterious life lurks thereSlide 2 of 15
Mysterious life lurks there
Though 94 percent of life on Earth is aquatic, about two-thirds of all marine life remains unidentified. New species are constantly being discovered, raising more questions about marine life.
This year, the SUNY College of Environmental Science and Forestry's (ESF) annual list of the Top 10 New Species included a striking red species of sea dragon that remained undiscovered despite living in shallow waters off the western coast of Australia.Slide 3 of 15
Spooky sounds from the deepSlide 4 of 15
Spooky sounds from the deep
It's not just the flora and fauna of the oceans that remain mysterious to scientists; there are a handful of sounds from the depths of the oceans that scientists cannot explain with any certainty.
"The Bloop" may be the most famous underwater sound, captured in 1997 by hydrophones set out by the National Oceanic and Atmospheric Administration (NOAA). It is one of the loudest ocean sounds ever recorded, and while the noise is consistent with an underwater ice quake — a large iceberg fracturing — no one knows for sure what made the sound. [Listen to 6 Spooky Sounds from the Deep Sea]
Because the Bloop mimics marine animal sounds, many people have jokingly linked the noise to Cthulhu, a fictional part-octopus monster created by sci-fi writer H.P. Lovecraft in 1928. The Bloop's volume is too great to be made by any sea creatures known to science, but there are innumerable creatures still unknown.Slide 5 of 15
Underwater lakes and riversSlide 6 of 15
Underwater lakes and rivers
Oceans have lakes, and rivers, that exist underwater. How?
When seawater seeps through thick layers of salt, the salt dissolves and forms depressions in the seafloor. NOAA explains that dissolved salt also makes the water in that area denser, and as such, it will settle into the depressions. These underwater lakes and rivers, also known as brine pools, are similar to their land-based counterparts — they have shorelines, and even waves.Slide 7 of 15
Hidden waterfallsSlide 8 of 15