But the ocean will never be fully explored. How Much of the Seafloor is Left to Explore. Home Ocean Exploration Facts How much of the ocean has been explored? How much of the ocean has been explored? The ocean is vast, yet only a small fraction has been explored. Yet sending anything to the ocean depths, human or machine, is expensive, and both scientists said funding is a constant issue. Enter British tycoon Richard Branson , who announced plans earlier this year to send humans, aboard newfangled submersibles, to the five deepest spots on Earth.
The deepest is the Mariana Trench in the western Pacific Ocean, an eye-popping 36, feet 11, meters below the surface — more than a mile deeper than Mount Everest is tall. Humans have visited this trench only once , in , when the Trieste, a deep-diving craft purchased by the U. Navy, spent about 20 minutes parked on the ocean floor. The two humans aboard the Trieste were U. Navy Lt. Don Walsh and Swiss scientist Jacques Piccard, co-designer of the remarkable vessel. To this day, their dive has been unmatched.
Clearly, supply is not the issue—so how did water find its way to Earth? The answer lies within asteroids literally. Recent observations have hinted that ice, and possibly liquid water, exist in the interiors of asteroids and comets.
This fact suggests that any planet in the path of an asteroid hurtling through space could receive water in the same way. Looking to our nearest neighbors—Venus and Mars—it would appear that this is exactly the case. So, where are their oceans? More and more heat became trapped under an increasingly thick blanket of atmospheric water vapor, a powerful greenhouse gas Figure 1.
Meanwhile, any remaining water vapor continued to rise past the atmosphere and was eventually lost to space. Liquid water on ancient Mars, on the other hand, was likely sparse due to frigid temperatures locking any hopeful seas in ice. Nowadays, Mars only maintains reservoirs of water frozen in its ice caps and trapped beneath the soil. Given the harsh effects of the Sun on the oceans of both Venus and Mars, it may seem like Earth is the only planet in our Solar System that is perfectly positioned to host a large liquid body of water.
Earth is neither too hot i. However, contrary to common intuition, being located in the Goldilocks Zone is not the only way to maintain a liquid ocean Figure 2. That said, an alien from our outer Solar System would consider the Mariana Trench as shallow as a puddle. More than 80 percent of the ocean is unmapped and unexplored , which leaves open the question of how many species there are yet to be discovered.
At the same time, the ocean hosts some of the world's oldest creatures: Jellyfish have been around more than half a billion years , horseshoe crabs almost as long. Other long-lived species are in crisis. The tiny, soft-bodied organisms known as coral , which form reefs mostly found in shallow tropical waters, are threatened by pollution, sedimentation, and global warming.
Researchers are seeking ways to preserve fragile, ailing ecosystems such as Australia's Great Barrier Reef. Human activities affect nearly all parts of the ocean. Lost and discarded fishing nets continue to lethally snare fish , seabirds, and marine mammals as they drift.
Ships spill oil and garbage; they also transport critters to alien habitats unprepared for their arrival, turning them into invasive species. Mangrove forests are cleared for homes and industry. Our garbage— particularly plastic —chokes the seas, creating vast " garbage patches " such as the Great Pacific Garbage Patch. Fertilizer runoff from farms turns vast swaths of the ocean into dead zones, including a New Jersey-size area in the Gulf of Mexico.
Climate change , the term scientists now use to describe global warming and other trends currently affecting the planet because of high greenhouse gas [1] emissions from humans, is strikingly reflected in the oceans.
The greenhouse gas carbon dioxide is also turning ocean waters acidic, and an influx of freshwater from melting glaciers threatens to alter the weather-driving currents: the Atlantic Ocean's currents have slowed by about 15 percent over the past few decades.
A community of scientists, explorers , and citizen scientists continues to study the ocean, hoping that more information will yield more paths for conservation.
Underwater drones , for example, are being deployed to explore undersea frontiers, while new tools are helping scientists measure and understand what they find. Read more about ocean threats and solutions here. Humans rarely encounter frilled sharks, which prefer to remain in the oceans' depths, up to 5, feet 1, meters below the surface. Considered living fossils, frilled sharks bear many physical characteristics of ancestors who swam the seas in the time of the dinosaurs. This 5.
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