“The intense pressures in the
In fact, most of the waters remain unexplored, uncharted and unseen by our eyes. It might be shocking to find out, but only 5% of the ocean has been explored and charted by humans. The rest, especially its depths, are still unknown.
A handful of divers in submersibles have made their way down to the bottom, but because of a lack of oxygen and deep-sea pressure, they've only explored for short periods of time.
Unlike mapping the land, we can't measure the landscape of the sea floor directly from satellites using radar, because sea water blocks those radio waves.
Despite modern technologies, only 5 percent of the oceans have been explored. As such, the remaining 95 percent remains untouched, unseen, and undiscovered to date. Regarding marine species, scientists have yet to discover how many exist in the oceans.
On 23 January 1960, two explorers, US navy lieutenant Don Walsh and Swiss engineer Jacques Piccard, became the first people to dive 11km (seven miles) to the bottom of the Mariana Trench. As a new wave of adventurers gear up to repeat the epic journey, Don Walsh tells the BBC about their remarkable deep-sea feat.
The oceans cover 70% of the world's surface, and despite what you have seen on nature documentaries, most of the ocean is empty, dark, cold, and void of mammalian life. However, unlike the land, the ocean exists in three dimensions.
“The intense pressures in the deep ocean make it an extremely difficult environment to explore.” Although you don't notice it, the pressure of the air pushing down on your body at sea level is about 15 pounds per square inch. If you went up into space, above the Earth's atmosphere, the pressure would decrease to zero.
The seafloor has distinct features and characteristics that help us better understand Earth's current and past conditions, potential resources, and natural hazards. However, less than 10% of the seafloor has been mapped globally.
The ocean floor covers more than 70 percent of the planet's surface. Like dry land, the ocean floor has various features including flat plains, sharp mountains, and rugged canyons (Fig. 7.1). However, the lowest point in the world ocean is much deeper than the highest point on land.
Features of the ocean include the continental shelf, slope, and rise. The ocean floor is called the abyssal plain. Below the ocean floor, there are a few small deeper areas called ocean trenches. Features rising up from the ocean floor include seamounts, volcanic islands and the mid-oceanic ridges and rises.
The least saline ocean, by comparison, is the Arctic Ocean, which has a typical salinity of 28–30 g/kg owing to the low rate of evaporation and meltwater from the ice-caps.
The deepest part of the ocean is called the Challenger Deep and is located beneath the western Pacific Ocean in the southern end of the Mariana Trench, which runs several hundred kilometers southwest of the U.S. territorial island of Guam. Challenger Deep is approximately 10,935 meters (35,876 feet) deep.
More than eighty percent of our ocean is unmapped, unobserved, and unexplored. Much remains to be learned from exploring the mysteries of the deep.
Last year an expedition to the Mariana Trench made history by conducting the deepest crewed dive ever completed as it descended 10,927 metres into the Challenger Deep.
To summarize, while the body of water of the sea cannot be owned by anyone, the seabed is owned by the coastal State within the limits of the "territorial sea" and not beyond. However, property rights are not the only way to "control" the sea.
Why are there no oceanic rocks older than 200 million years? Oceanic crust is eventually destroyed in subduction zones. Although oceanic crust has been forming on Earth for over 4 billion years, all of the sea floor older than about 200 million years has been recycled by plate tectonics.
To date, ships have charted only a small fraction of the seafloor. But thanks to gravity, the ocean surface has broad bumps and dips that mimic the topography of the ocean floor. These bumps and dips can be mapped using a very accurate radar altimeter mounted on a satellite.
Light may be detected as far as 1,000 meters down in the ocean, but there is rarely any significant light beyond 200 meters.
Light in the ocean decreases with depth, with minimal light penetrating between 200-1,000 meters (656-3,280 feet) and depths below 1,000 meters receiving no light from the surface.
Therefore, the deep ocean (below about 200 meters depth) is cold, with an average temperature of only 4°C (39°F). Cold water is also more dense, and as a result heavier, than warm water. Colder water sinks below the warm water at the surface, which contributes to the coldness of the deep ocean.
And, of all the Earth's water, 97 percent is saltwater, only 1 percent is fresh water available for humans to drink, and 2 percent is frozen.
According to researchers, every year the Pacific Ocean decreases in size by a few centimeters, and with depictions from a supercomputer, they expect a new continent will form in 200 to 300 million years.
Several animals observed in the biocube were photographed with the ROV because of their large size and extremely delicate gelatinous bodies. As in all habitats, most animals in the midwater are tiny—microscopic crustaceans like copepods and amphipods, worms, sea butterflies, and a myriad of other unusual species.