The Mariana Trench Is 36,070 Feet Deep — Here's What Lives There

The deepest part of the ocean is the Challenger Deep, a trench within the Mariana Trench in the Pacific Ocean, reaching a verified depth of approximately 36,070 feet (10,994 meters). This extreme environment, located near Guam, experiences pressures over 1,000 times greater than at sea level. Only a handful of crewed and uncrewed missions have successfully reached this point, revealing unique geological formations and life forms adapted to total darkness and crushing pressure.

What Is the Deepest Part of the Ocean?

The deepest part of the ocean is the Challenger Deep, located at the southern end of the Mariana Trench in the Pacific Ocean. According to the National Oceanic and Atmospheric Administration (NOAA, 2021), its maximum verified depth is 36,070 feet (10,994 meters). This point is nearly 7 miles below the ocean’s surface, making it the deepest known location on Earth’s seafloor. The trench itself was formed by the subduction of the Pacific Plate beneath the Mariana Plate, a process that continues to shape the region.

How Deep Is the Mariana Trench Compared to Other Ocean Trenches?

The Mariana Trench is the deepest oceanic trench on Earth, but it is not the only one. The following table compares the Mariana Trench to other major deep-sea trenches, based on data from the General Bathymetric Chart of the Oceans (GEBCO, 2023).

Trench Name	Location	Maximum Depth (feet)	Maximum Depth (meters)	Key Feature
Mariana Trench	Western Pacific Ocean	36,070	10,994	Contains Challenger Deep, the deepest point
Tonga Trench	South Pacific Ocean	35,702	10,882	Second deepest trench on Earth
Philippine Trench	Philippine Sea	34,580	10,540	Also known as the Mindanao Trench
Kuril-Kamchatka Trench	Northwest Pacific Ocean	34,449	10,500	Located near Japan and Russia
Kermadec Trench	South Pacific Ocean	32,963	10,047	Runs northeast of New Zealand

The Mariana Trench is approximately 368 feet deeper than the Tonga Trench, the second deepest. This difference, while small in percentage terms, represents a significant increase in pressure and environmental extremity.

What Is the Pressure at the Bottom of the Challenger Deep?

At the bottom of the Challenger Deep, the pressure is over 1,000 times the standard atmospheric pressure at sea level. Specifically, the pressure is approximately 15,750 pounds per square inch (psi), or 108.6 megapascals (MPa), according to the Woods Hole Oceanographic Institution (WHOI, 2022). This extreme pressure is equivalent to the weight of about 50 jumbo jets stacked on top of a person. It is so intense that it would instantly crush any conventional submarine not specifically designed for hadal depths. Only specialized deep-submergence vehicles, such as the DSV Limiting Factor used by explorer Victor Vescovo, are built to withstand this environment.

Who Has Visited the Deepest Part of the Ocean?

Only a small number of people have successfully visited the Challenger Deep. The first descent was made in 1960 by U.S. Navy Lieutenant Don Walsh and Swiss engineer Jacques Piccard in the bathyscaphe Trieste. The next crewed visit did not occur until 2012, when filmmaker James Cameron descended solo in the Deepsea Challenger. Since then, several expeditions led by explorer Victor Vescovo in the DSV Limiting Factor have made multiple dives, including the first all-female crewed descent in 2023. According to the Five Deeps Expedition (2019), Vescovo’s team completed the first crewed dives to the deepest point of all five of the world’s oceans.

What Life Exists at the Bottom of the Mariana Trench?

Life in the hadal zone, the region below 20,000 feet, is adapted to extreme pressure, total darkness, and near-freezing temperatures. According to a 2023 study published in Deep Sea Research Part I, researchers identified the Mariana snailfish (Pseudoliparis swirei) as the deepest-dwelling fish ever recorded, observed at 26,831 feet (8,178 meters). Other organisms include giant amphipods (shrimp-like crustaceans), xenophyophores (single-celled organisms that can grow to 4 inches across), and various microbial communities. These life forms have evolved unique biochemical adaptations, such as piezolytes (molecules that stabilize proteins under high pressure), to survive in this environment.

How Was the Depth of the Ocean Measured?

Ocean depth is measured using sonar technology, specifically echo sounding. A ship sends a sound wave toward the seafloor, and the time it takes for the echo to return is used to calculate depth. Modern multibeam sonar systems, like those used by the Schmidt Ocean Institute (2024), can map the seafloor in high resolution, revealing features as small as a few meters across. The Challenger Deep’s depth was first measured by the British survey ship HMS Challenger in 1875 using a weighted rope, which recorded a depth of 26,850 feet. Today, the most precise measurements come from pressure sensors on submersibles and advanced sonar mapping.

What Are the Key Milestones in Deep Sea Exploration?

Deep sea exploration has progressed significantly over the past 150 years. The following timeline highlights major milestones, based on data from the National Geographic Society (2023) and the Scripps Institution of Oceanography (2022).

Year	Milestone	Entity/Person	Significance
1875	First depth measurement of Challenger Deep	HMS Challenger expedition	Recorded 26,850 feet using a weighted rope
1960	First crewed descent to Challenger Deep	Jacques Piccard and Don Walsh in Trieste	Proved humans could reach the deepest point
1995	First uncrewed survey of Challenger Deep	Japanese ROV Kaikō	Collected sediment and biological samples
2012	First solo crewed descent	James Cameron in Deepsea Challenger	Conducted scientific observations and filming
2019	First crewed dives to all five ocean deeps	Victor Vescovo in DSV Limiting Factor	Completed the Five Deeps Expedition
2023	First all-female crewed descent	Dawn Wright and others in DSV Limiting Factor	Advanced diversity in deep sea exploration

Why Is the Deep Sea Important for Scientific Research?

The deep sea, including the hadal zone, is a critical frontier for scientific discovery. According to a 2025 report from the Intergovernmental Oceanographic Commission (IOC), deep sea ecosystems play a vital role in global carbon cycling, with hadal trenches acting as carbon sinks that sequester organic matter. Additionally, organisms from these depths are being studied for potential biomedical applications, including novel enzymes and antibiotics. The extreme conditions also provide a natural laboratory for studying the limits of life on Earth, which informs the search for life on other planets, such as Jupiter’s moon Europa.

How Does the Deep Sea Relate to Climate Change?

The deep sea is directly connected to climate regulation. The ocean absorbs about 30% of human-caused carbon dioxide emissions, according to the Intergovernmental Panel on Climate Change (IPCC, 2023). Deep ocean currents, driven by temperature and salinity differences, transport heat and carbon around the globe. The hadal zone, while remote, is not immune to human impact. A 2024 study in Nature Geoscience found microplastics in sediment samples from the Mariana Trench, indicating that pollution reaches even the deepest parts of the ocean. This underscores the need for continued research and conservation efforts.

What Are the Future Plans for Deep Sea Exploration?

Future exploration of the Challenger Deep and other hadal zones is focused on sustained observation and technological advancement. The National Science Foundation (NSF) announced in 2025 a new initiative to deploy long-term seafloor observatories in the Mariana Trench, equipped with sensors to monitor temperature, pressure, and biological activity. Additionally, private companies like OceanX are developing next-generation submersibles capable of carrying multiple scientists to hadal depths. These efforts aim to transform deep sea exploration from occasional dives into continuous scientific monitoring.