The average depth of the ocean is about 3,682 meters (12,080 feet). 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.
What limits human exploration of deep-sea environments? The limitations of human exploration in deep-sea environments are primarily due to depth-related challenges, including increased pressure, decompression sickness risk, and orientation difficulties, which often require specialized equipment and training.
How deep is the ocean? At nearly seven miles, the deepest part is a mile longer than Mount Everest is tall.
The average depth of the oceans is about 4 km. More precisely the average depth is 3,688 meters (12,100 ft).
The very deepest depth of the ocean is roughly 2,000 meters deeper than Mount Everest is tall—36,070 feet deep (10,994 m)! Each zone has a different mix of species adapted to its specific light level, pressure, temperature, and community.
At around 300 feet, no visible light can penetrate the water at all!
Summary: 2025 is a transformative year for ocean governance, marked by three landmark events: the UN BBNJ Convention entering into force, new WTO fisheries subsidies regulations taking effect, and the adoption of a historic political declaration at the 2025 UN Ocean Conference.
More than 70% of our planet is ocean – and 90% of that ocean is deep sea.
Challenger Deep, at approximately 36,070 feet (10,994 meters). How does it compare to the height of Mount Everest? Mount Everest is 29,029 feet (8,848 meters) tall. Everest would fit completely submerged in the Mariana Trench and still have over a mile (1.6 kilometers) of water above it.
The two ions that are present most often in seawater are chloride and sodium. These two make up over 90% of all dissolved ions in seawater. The concentration of salt in seawater (its salinity) is about 35 parts per thousand; in other words, about 3.5% of the weight of seawater comes from the dissolved salts.
Today, over 80% of the global ocean (and 50% of the U.S. Ocean) is still unmapped, with even more unexplored. One of the biggest challenges of ocean exploration is the intense pressures in the deep ocean. In addition, zero visibility and extreme cold temperatures make it difficult to explore the vast ocean.
From large spindly crabs to surprisingly adorable octopuses, discover some of the wonderfully unique animals that live many leagues under the sea.
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.
We have a great deal more to learn about our ocean and what resides within it, but progress IS being made. We learn more and more each year. We continue to discover new features and creatures, clues to our past, and resources that can improve our future. But the ocean will never be fully explored.
Psalm 104:25-26 – “There is the sea, vast and spacious, teeming with creatures beyond number-living things both large and small. There the ships go to and fro, and Leviathan, which you formed to frolic there.” Psalm 95:5 – “The sea is his, for he made it, and his hands formed the dry land.”
The 7 biggest ocean mysteries scientists can't explain
Up there, the air is only about one-third of what it is at sea level. The extreme thin air makes it difficult for engines in planes or helicopters to work properly to keep the aircraft flying. Besides, the harsh and unpredictable weather on top of Mount Everest is another challenge.
The 2 PM Rule on Mount Everest is a critical safety guideline used by climbers and guides during the summit push. It advises that climbers must reach the summit no later than 2:00 PM and begin descent, regardless of how close they are to the top.
He reached the bottom of the Mariana Trench in the submersible vessel Deepsea Challenger, diving to a depth of 10,908 m (35,787 ft; 5,965 fathoms).
Distribution of countries according to their share of the Earth's surface. The largest countries in terms of area are Russia (3.35%), Canada (1.96%) and China (1.88%). Together they occupy about 7.2% of the Earth's surface.
Scientists estimate that roughly half of the oxygen production on Earth comes from the ocean. The majority of this production is from oceanic plankton — drifting plants, algae, and some bacteria that can photosynthesize.
3% of the earth's water is fresh. 2.5% of the earth's fresh water is unavailable: locked up in glaciers, polar ice caps, atmosphere, and soil; highly polluted; or lies too far under the earth's surface to be extracted at an affordable cost. 0.5% of the earth's water is available fresh water.
Our Biggest Stories of 2025: From Climate Politics to AI and...
Climate Change. Climate change represents the fastest-growing and most intense threat facing the global ocean.
The global mean near-surface temperature from January to August 2025 was therefore lower than 2024 – at 1.42 °C ± 0.12 °C above the pre-industrial average, compared to about 1.55 °C ± 0.13 °C for the year 2024.