The Mysteries of the Mariana Trench

Our ocean is an incredibly vast and mysterious place. And there is no place where that is more evident than the deepest ocean area in the world: the legendary Mariana Trench. Located east of the Philippines, the Mariana Trench lies in the Mariana Archipelago in the western portion of the North Pacific. The greater area of the Mariana Trench Marine National Monument is made up of more than 95,000 square miles of ocean. Beneath these waters lie incredibly complex aggregations of submerged islands and volcanoes … and of course, an astoundingly massive trench.

Dive in with us to have your biggest questions answered about the famed Mariana Trench.

How deep is the Mariana Trench?

The deepest part of the Mariana Trench, known as Challenger Deep, is almost 36,000 feet below the ocean’s surface. For context, Mount Everest is about 29,000 feet above sea level, so the Mariana Trench is about 7,000 feet deeper than Mount Everest is tall. For one more comparison, the RMS Titanic lies at a depth of about 12,500 feet below sea level. The Challenger Deep is in waters nearly three times deeper than this ship’s final resting place.

Due to its enormous size, the Mariana Trench has at times been affectionately nicknamed the Grand Canyon of the ocean. This is certainly a picturesque image, but don’t let the mammoth size of this U.S. national terrestrial park fool you into thinking the Mariana Trench matches its size. The trench’s footprint is estimated to be 120 times larger than the Grand Canyon’s, and to reach the bottom of Challenger Deep, you’d need to descend through almost six Grand Canyons stacked on top of each other before you’d reach the seafloor.

Oh … and did we mention it’s five times wider than it is deep?  It’s about 43 miles wide!

What is Challenger Deep, and how long would it take to reach it?

Challenger Deep is the deepest point of the Mariana Trench. Fewer than 30 people have ever journeyed to this area. The trek below the surface is long, dark and time-consuming, and it’s not an expedition considered lightly by scientists and explorers.

The first people to descend into the depths of this area in 1960 were oceanographers Jacques Piccard and Don Walsh, and it took them close to five hours to reach Challenger Deep. Since then, more advanced submersibles have been created, but it still takes two to four hours for modern vessels to reach such depths. For example, explorer and filmmaker James Cameron reached the seafloor in a little more than 2.5 hours in the first documented solo submarine dive to the area, and it took oceanographer Dr. Dawn Wright about four hours in 2022. It is crucial that these submersibles descend slowly and steadily beneath the surface, as the immense water pressure compounds with every mile a submersible descends. Speaking of pressure …

Get Ocean Updates in Your Inbox

Sign up with your email and never miss an update.

This field is hidden when viewing the form

Campaign ID(Required)

Email(Required)

Name(Required)

First Last

By providing your email address, you consent to receive emails from Ocean Conservancy.
Terms & Conditions and Privacy Policy

This field is hidden when viewing the form

Email Opt-in: Selected(Required)

Yes, I’d like to receive occasional emails from Ocean Conservancy.

What is the water pressure at the bottom of the Mariana Trench?

If you thought the depth of the Mariana Trench was its only jaw-dropping feature, think again. Water pressure is one of the most important factors affecting deep-sea life. In the ocean, pressure increases by one atmosphere for every 33 feet (10 meters) of depth. One atmosphere (a unit of measurement for pressure equivalent to average air pressure at sea level) is equal to about 14.7 pounds per square inch (PSI), which is the approximate standard atmospheric pressure at sea level. If you were to convert atmospheric pressure into weight, one atmosphere is about the weight of a bowling ball. Stay with me, friends.

If a vessel were to dive 2,000 feet below the surface, the pressure would equal that of 60 bowling balls stacked atop every square inch of that submersible. But 60 bowling balls is simply nothing compared to the pressure in the Mariana Trench. The atmospheric pressure at the depths of Challenger Deep is equal to about 16,000 PSI. That pressure is about the same as the weight of an entire full-grown elephant on every square inch of a submersible!

Need a more extreme comparison? If a human were to be placed at the bottom of the Mariana Trench, the pressure would be equal to that of 50 jumbo jets piled on top of a person!

Do any animals live in the Mariana Trench?

The depths of the Mariana Trench come with immense pressure and extreme darkness, but somehow, life finds a way to survive. Organisms that live at an extreme depth, like that of Challenger Deep, have to be highly adapted to low temperatures (typically just above freezing), high pressure and virtually no light at all.

Species found in the depths of the Mariana Trench might look vastly different from animals from other ocean depths because their anatomy has been refined to thrive in harsh conditions. At such great depths, these animals typically depend on chemosynthesis (using nutrient-rich waters being pumped out of hydrothermal vents) or descending detritus (dead matter that has fallen from higher parts of the ocean) for food, such as whale falls. Just a handful of these animals include species of octopuses and squids, sea cucumbers, amphipods, sea jellies, shrimp, sea worms and some wild-looking fish!

In 2025, more than 7,000 new species were discovered in the Mariana Trench, including the hadal snailfish (Pseudoliparis swirei). This is the deepest-dwelling fish currently known to science. Now, the fish has been dubbed “the Mariana snailfish.”

This ghost fish, of the family Aphyonidae, was filmed alive for the first time during a deep-sea dive. Observations like this are critical to understanding an organism’s life. We now have the first evidence of where these fish live!

How was the Mariana Trench formed?

The process by which the Mariana Trench was created is a geologically fascinating one known as subduction. On the Earth’s surface, there are thin plates that cover the planet’s mantle, which is made of molten rock. If two of these plates collide, one pushes down into the Earth’s mantle while the other is pushed over the bottom plate. When this happens, a trench is formed from the drag of the bottom plate. This process can sometimes create incredibly strong earthquakes. The plates that forged the Mariana Trench’s creation are estimated to be up to approximately 180 million years old.

This trench was unknown to scientists until 1875. It was then that a team of explorers on the HMS Challenger measured the depth of the sea by simply lowering a weighted rope into the water. They were baffled when they measured that first portion of the seafloor to be five miles below the surface. And so was born the origin of some of the most daring deep-sea explorations known to mankind to date.

Is the Mariana Trench protected?

The Mariana Trench is in waters off Guam and the Mariana Islands. The region is protected from some human activities under its status as a marine monument. The creation of the Mariana Trench Marine National Monument signified that international, national and local leaders all recognize the importance of protecting this area.

However, just because the region is protected does not mean it’s not vulnerable to modern threats to ocean health. Plastic bags have been spotted in the Mariana Trench during several expeditions, highlighting the far-reaching impact of the marine debris problem. No corner of our ocean is safe from the ever-present threat of plastic pollution. The reality of a changing climate makes the future well-being of wondrous places like the Mariana Trench uncertain. What’s more: More than 70% of the global ocean has yet to be mapped. And what we don’t yet know about, we cannot wisely work to protect.

It’s up to us to work together to defend our ocean, from the sandy shores of our favorite beaches to the deepest, darkest parts of the sea. Together, we can work to protect our ocean as a whole, which ultimately helps protect treasured places like Challenger Deep.

Find out how you can join Ocean Conservancy’s wave of momentum to secure a healthy ocean and a thriving planet, forever and for everyone!

The post The Mysteries of the Mariana Trench appeared first on Ocean Conservancy.

from Ocean Conservancy https://ift.tt/iCaDpzn https://ift.tt/g3C7fVO

The Ocean is Changing—Here’s What We Can Do About It

Our ocean has absorbed more than 90% of excess heat caused by human-driven climate change and a quarter of the carbon dioxide we emit. In simple terms: The ocean has been quietly protecting us from the worst impacts of a warming planet.

But that protection comes at a high cost. 

In “Ocean Discovery: Climate and Our Ocean,” actor and Protect Where We Play Team Ocean Captain John Slattery sits down with Ocean Conservancy’s Vice President of Climate Fatima Candace Vahlsing to explore what’s happening beneath the surface—and what we can do about it.

The ocean is the climate story.

We often think about climate change as an atmospheric story, but the ocean is the engine of our climate system. It regulates temperatures, drives weather patterns and produces roughly half of the oxygen we breathe. And right now, that engine is under enormous pressure.

Currently, we’re facing a triple planetary crisis: The ocean is warming, becoming more acidic and experiencing rising sea levels. These aren’t distant or abstract problems. They’re measurable changes with consequences we can already see. 

Take coral reefs. They support roughly one-quarter of all marine species, but when ocean temperatures rise, corals can bleach and, if the stress continues, ultimately die. Today, 77% of the world’s reef areas have experienced bleaching-level heat stress.

Ocean acidification is another consequence of our changing climate. As the ocean absorbs carbon dioxide, seawater becomes more acidic. Ocean acidity has increased by about 30% since the Industrial Revolution, making it harder for animals like oysters, clams, sea urchins and some plankton to build and maintain their shells and skeletons. 

When the foundation of the ocean’s food web and ecosystem is disrupted like this, the effects ripple outward—to fish and wildlife, to coastal communities and ultimately to all of us. 

This is a human story, too.

For hundreds of millions of people around the world, a healthy ocean is inseparable from food, livelihoods and culture. Coastal fishing communities, small island nations and Indigenous communities are among those facing some of the most immediate impacts, despite contributing comparatively little to the climate crisis. Here in the United States, rising sea levels are already making high-tide flooding more common.

That’s why understanding the science matters. The numbers tell us what’s happening. They also point us toward where we need to act. 

The ocean can be part of the solution.

The good news is that this story doesn’t end with what’s going wrong. Protecting important ocean areas, like mangroves, marshes and wetlands, can give ecosystems room to recover. Clean ocean energy, including responsibly developed offshore wind, can help reduce the greenhouse gas pollution driving climate change.

Ocean Conservancy is working with partners around the world to advance these and other ocean-based climate solutions while supporting the science to explore new opportunities. 

The solutions are real. The progress is real. And so is the opportunity to make a difference.

As John puts it, the ocean has been taking care of us. It’s time we returned the favor. Watch Ocean Discovery: Climate and Our Ocean to hear Fatima and John unpack the science, the stakes and the solutions—and then take the next step.

Take action to combat the climate crisis from right where you are. Our elected officials must act now to move away from dirty fossil fuels that exacerbate climate change and move toward clean energy. Add your name today.

Whether you’re learning more, sharing what you’ve learned or raising your voice with decision-makers, your action matters. Together we can protect the ocean that protects us. 

Combat the Climate Crisis

Our elected officials must act now to move away from dirty fossil fuels that exacerbate climate change and move toward clean energy. Add your name today.

TAKE ACTION

The post The Ocean is Changing—Here’s What We Can Do About It appeared first on Ocean Conservancy.

from Ocean Conservancy https://ift.tt/78BngmF https://ift.tt/7ML3qtm

The Annual Migration to Clean Up Our Coasts

Annually, seasonally and sometimes even daily, amazing oceanic migrations are taking place. Humpback whales migrate thousands of miles to breeding grounds each year, while every night trillions of plankton, fish and squid move from the depths of the ocean towards the surface to feed. There are dozens more examples. Generation after generation, these incredible treks take place like clockwork.

There’s another migration I would like to add to the list. Each year, hundreds of thousands of people flock to shores across the world to remove harmful debris and plastic from their creeks, rivers, lakes and beaches. This is Ocean Conservancy’s International Coastal Cleanup® (ICC), and its 41^st season is upon us. I personally am extra-excited about this year’s movement, as it will be the first cleanup with my eight-month-old in tow, hopefully her first of many. 

About the ICC

The ICC brings together people of all ages and backgrounds to take part in removing trash from the environment. The beauty of this migration is that even the smallest actions add up to great impact for ocean health. While many community cleanups take place in September, cleanups happen all year long. You can also do a cleanup any time on your own or with family and friends using Ocean Conservancy’s free mobile app, Clean Swell®, to track what you find. Data collection is at the heart of the ICC, and millions of marine debris data points feed into an online open-access database which informs big-picture solutions to the ocean plastic crisis. During last year’s Cleanup, more than 630,000 volunteers removed 7.9 million pounds (3.4 million kilograms) of trash and tallied 13.8 million items removed!

Our cleanup actions have immediate benefits for marine life too. Based on recent research led by Ocean Conservancy scientists, we built a Wildlife Impact Calculator to help us understand how our actions removing plastic from the environment protect marine birds, turtles and mammals that otherwise might have interacted with those items. The calculator is now part of the Clean Swell® app, so when you submit your cleanup results, you can see in real time how many animals your cleanup effort is protecting.

If you are like me, once you start this movement to clean our waterways and ocean, it becomes part of your yearly routine. It’s an annual migration of good for our blue planet—one where we can bring our families and friends along too.

What the ocean means to you

We recently asked our supporters: What does the ocean mean to you, and why do you feel called to protect it? Here are some of the responses they shared with us:

“I would love for future generations to be able to see the beautiful ocean we have. We need to stop the destruction of pollution, overfishing and warming of our oceans.” – Debra E.

“It is our future! And it is an honor to explore it at times. I wish everyone could see its beauty below the surface.” – Suzy W.

“It’s one of the most important places on the planet and it is still as unknown to us as outer space, for this is the final frontier to be explored. And now more than ever, our future depends on a healthy thriving ocean.” – Derek H.

“The ocean and wildlife were part of my childhood. It was where I felt like I belonged. I want to protect it so future generations can have the connection that I had.” – Cynthia K.

“The ocean is life itself; a vast, breathing force whose rhythms sustain the planet, nourish entire ecosystems, and cradle an extraordinary tapestry of wildlife. It embodies natural beauty in its purest form, from shimmering surfaces to the hidden worlds below, each layer reminding us of the delicate balance that keeps Earth alive. Without the ocean, all life ends; with it, the planet thrives. It is both a wonder and a responsibility, a reminder that we must protect the oceans if we hope to protect ourselves and the future of every living thing.” – Laurie S.

Looking to the future

Like so many of our supporters, I dream of a future where my daughter and her generation do not have to do cleanups, and the plastic pollution crisis would be a thing of the past. And that dream is not too far away. The tools and solutions exist, we just have to prioritize and implement them. Cleaning up the debris and plastics already in the environment remains an important part of the solution. Join our International Coastal Cleanup® and help us reach our mission of a healthy ocean and a thriving planet, forever and for everyone.

Get Ocean Updates in Your Inbox

Sign up with your email and never miss an update.

This field is hidden when viewing the form

Campaign ID(Required)

Email(Required)

Name(Required)

First Last

By providing your email address, you consent to receive emails from Ocean Conservancy.
Terms & Conditions and Privacy Policy

This field is hidden when viewing the form

Email Opt-in: Selected(Required)

Yes, I’d like to receive occasional emails from Ocean Conservancy.

The post The Annual Migration to Clean Up Our Coasts appeared first on Ocean Conservancy.

from Ocean Conservancy https://ift.tt/rd2JNn0 https://ift.tt/tsCAN8P