the challenger deep voyage

The Challenger Expedition

Modern oceanography began with the Challenger Expedition between 1872 and 1876. It was the first expedition organized specifically to gather data on a wide range of ocean features, including ocean temperatures seawater chemistry, currents, marine life, and the geology of the seafloor. For the expedition, HMS Challenger, a British Navy corvette (a small warship) was converted into the first dedicated oceanographic ship with its own laboratories, microscopes and other scientific equipment onboard. The expedition was led by British naturalist John Murray and Scottish naturalist Charles Wyville Thompson. Thompson had previously dredged some curious creatures from the ocean depths in the North Atlantic and the Mediterranean Sea, and these discoveries persuaded the British government to launch a worldwide expedition to explore the ocean depths. The Challenger Expedition left Portsmouth, England, just before Christmas in 1872. The ship had many different types of samplers to grab rocks or mud from the ocean floor, and nets to capture animals from different levels in the ocean. Challenger also had different winches-mechanical engines used to lower and hoist sounding lines to measure how deep the ocean was. At each sampling station, the crew lowered trawls, nets and other samplers to different depths, from the surface to the seafloor, and then pulled them back on board loaded with animals or rocks.

Challenger first traveled south from England to the South Atlantic, and then around the Cape of Good Hope at the southern tip of Africa. It then headed across the wide and very rough seas of the southern Indian Ocean, crossing the Antarctic Circle, and then to Australia and New Zealand. After that, Challenger headed north to the Hawaiian Islands, and then south again around Cape Horn, at the southern tip of South America where the Pacific and Atlantic Oceans meet. After more exploration in the Atlantic, Challenger returned to England in May of 1876.

Among the Challenger Expedition’s discoveries was one of the deepest parts of the ocean—the Marianas Trench in the western Pacific, where the seafloor is 26,850 feet, or more than 4 miles deep (8,200 meters). The deepest place in all the oceans is near where the Challenger took its sounding. It is now called the Challenger Deep and it is 37,800 feet deep (11,524 meters). The expedition also revealed the first broad outline of the shape of the ocean basin, including a rise in the middle of the Atlantic Ocean that we now know is the Mid-Atlantic Ridge. Scientists compiled the first systematic plots of currents and temperatures in the oceans. The Challenger Expedition’s exciting discoveries encouraged other countries to take interest in the oceans and to mount their own expeditions.

Fun Facts About the HMS Challenger

Expedition Crew 243

Scientists 6

Duration of Expedition 4 years 

Distance sailed 127,000 km (68,890 miles)

Number of sampling stations 362 

Number of depth soundings made 492 

Number of dredges taken 133 

Number of new species of animals and plants discovered 4,700

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H.M.S. Challenger: Humanity's First Real Glimpse of the Deep Oceans

The story of one of the most important expeditions in history..

We know more about the surface of the moon than about the ocean floor. Scientists estimate that 91 percent of life under the sea hasn’t been discovered yet and more than 80 percent of the ocean has never been explored.

What we do know about the ocean makes it almost more mysterious. It’s an alien landscape, complete with undersea mountain ranges and trenches deeper than Mount Everest is tall, home to a glorious nightmare carnival of weird, often glowing animals. And most of what we know has only come to light in the last 150 years, starting with the expedition of HMS Challenger .

From 1872 to 1876, the 200-foot-long warship was repurposed as a floating lab for the world’s first large-scale oceanographic expedition, circumnavigating the globe and dredging up samples of never-before-seen creatures from the ocean floor. The Challenger  explorers brought to light thousands of new species and revealed the oceans to be a place of startling depths and untold wonders. Scientists today still rely on the Challenger findings to study everything from seashells to climate change.

Sampling Another World

The Challenger expedition was inspired, in part, by that age-old motivation: to prove somebody wrong . In 1843, a naturalist named Edward Forbes posited that “the number of species and individuals diminishes as we descend, pointing to a zero in the distribution of animal life as yet unvisited” at depths below 1,800 feet.

But several small expeditions hinted that he couldn’t be right: HMS Lightning and (the incredibly named) HMS Porcupine found animals like clams, scallops, and corals at depths below Forbes’ theoretical limit. In light of these discoveries (and perhaps spurred by telegraph companies’ desire to create more undersea cables), the Royal Society of London for Improving Natural Knowledge approved a new, more thorough expedition: a three-year trip around the globe to plumb the ocean’s deepest basins, to ascertain the sea floor’s physical and chemical characteristics and to figure out just how far into the ocean’s depths life blooms.

Challenger set sail four days before Christmas in 1872 out of Portsmouth on the southern coast of England. There were about 250 men on board, including six scientists, who the naval officers and crew nicknamed “the Scientifics.” Challenger was a small warship retrofitted for a scientific mission; 15 of her 17 guns were removed to make room for laboratories and equipment.

Before they set sail, the ship’s steward’s assistant, a 19-year-old named Joe Matkin, wrote to his cousin, “All the Scientific Chaps are on board, and have been busy during the week stowing their gear away. There are some thousands of small air tight bottles, and little boxes about the size of Valentine boxes packed in iron tanks for keeping specimens in, insects, butterflies, mosses, plants, etc. There is a photographic room on the main deck, also a dissecting room for carving up bears, whales, etc.”

The ship also carried 181 miles of Italian hemp rope that would be used to measure the water’s depth and lower dredges to the sea floor.

Every few days, Challenger sounded, or plunged a weighted line into the water to determine how deep it was. They also recorded the ocean’s temperature at various depths and dragged a weighted net with a 10-foot-wide mouth across a patch of the ocean floor and hauled aboard the sea creatures and sediments it dredged up. 

Matkin wrote to his cousin, “When the dredge is hauled up [the scientists] stand round in their shirt sleeves, and commence overhauling the mud for fish etc., and as soon as they get any, down they all go to dissect and pickle them in glass jars.”

The crew sometimes brought in impressive specimens — one drawing from the expedition shows the crew hauling aboard a large shark, while two of the ship’s dogs watch warily.

Other times, though, the hauls were less exciting. “The mud! Ye gods, imagine a cart full of whitish mud, filled with minutest shells, poured all wet and sticky and slimy on to some clean planks,” wrote Sublieutenant Lord George Campbell about the sediments dredged from the sea floor. “In this the naturalists paddle and wade about, putting spadefuls in successively finer and finer sieves, till nothing remains but the minute shells.”

Read more : Australian scientists dredged the deep seafloor. Here's what they found

Deep Discoveries

They did this all the way around the world, from England to the North Atlantic and the Caribbean, down to Brazil and east to the southern tip of Africa. They dipped down within sight of Antarctic icebergs and then headed up, hugging Australia’s southeast coast and making their way through Micronesia and Asia, then east across the Pacific, tracing South America and arriving back in England on May 24, 1876, three and a half years after the journey’s start.

Halfway through the journey, in the spring of 1875, Challenger made one of its greatest discoveries: the Mariana Trench, containing the deepest point on Earth. The Mariana Trench is located near Guam, about 1,500 miles east of the Philippines. There, one of the Earth’s tectonic plates slips under another, resulting in a 1,580-mile-long groove in the sea floor.

At the lowest point Challenger recorded, the sea floor lay more than five miles below the water’s surface (later researchers would find that an even deeper point exists nearby, nearly seven miles deep). The crew wasn’t expecting the spot to be so deep; the first time they sent down a weight to measure the depth, they ran out of rope. When they sent down a thermometer, the glass cracked.

At the time, the scientists named it Swire Deep after one of the ship’s naval officers, though it’s since been renamed the Challenger Deep. Today’s scientists study the Mariana Trench to learn how tectonic plates shift and how plastic waste has reached even the remotest parts of the planet . All that work has its roots in the Challenger expedition.

Oddly, for one of the greatest scientific achievements of the voyage, the team wrote relatively little about exploring the deepest part of the ocean. In the naturalist Henry Moseley’s 520-page account of the expedition, he skips over the Mariana Trench entirely — all he says about that leg of the journey is that it was a “most tedious voyage.”

He did, though, find room for the following chapters from the same two-month period: “Habits of Gar-fish,” “Rice Fields,” and the nail-biter, “Fern Resembling a Liverwort.” (His and his colleagues’ reports also include jarringly racist descriptions of the people they met — a reminder that this culture of exploration can hide a dark side.)

Challenger ’s scientists were actually a little disappointed by the animals they found in the deep sea. Darwin had postulated that the deep sea would be full of organisms that had long since gone extinct on land; the scientists on board were let down when that didn’t seem to be true.

But the new animals they did find weren’t too shabby. The Challenger expedition returned with 4,700 never-before-seen species, including sea pigs (squishy pink potato-creatures that scoot around the sea floor on 14 legs) and faceless cusk-eels (foot-long fish with tiny, barely visible eyes and mouths on the underside of their chins, hence the “faceless”).

And even species that were already known still possessed the capacity to amaze. “A giant Pyrosoma was caught by us in the deep-sea trawl,” Moseley wrote of one of the specimens that caught his eye, a bioluminescent colony of tiny organisms that came together in a four-foot-long glowing tube. “I wrote my name with my finger on the surface of the giant Pyrosoma , as it lay on deck in a tub at night, and the name came out in a few seconds in letters of fire.”

Enduring Legacy

The thousands of specimens collected by Challenger are now housed in museums around the world, with the lion’s share going to London’s Natural History Museum . The specimens are still used in scientific research today.

“Just because they’re old, it doesn’t mean that they lose value. In fact ... in terms of looking at historical trends, they only increase in value with their age,” says Holly Morgenroth, a natural history curator at the Royal Albert Memorial Museum in Exeter, England. “The Challenger collection gives us what the seabed looked like 150 years ago. Without that, we could really only guess. It provides the evidence that we need to show that things have changed, or indeed if things have stayed the same.”

Read more : The Undiscovered Species Sitting on Museum Shelves

Using the expedition’s specimens and records , researchers are able to see if species live in the same places they did 150 years ago, compare potential new species to the original specimens discovered by the Challenger and explore the ways that climate change is affecting animals. Seashells from today are often thinner than the ones collected then, since extra carbon dioxide in the atmosphere can make the ocean more acidic — the seawater eats away at the shells.

And while the zoological specimens are some of Challenger ’s flashier legacies, another type of data from the expedition has proved critical to researchers in recent years: the ocean temperature logs.

“If you want to understand how much the world is warming today, you have to take into account things that happened before the Industrial Revolution,” says Jake Gebbie, an oceanographer at the Woods Hole Oceanographic Institute who published a paper in Science in 2019 about deep ocean temperatures over time using Challenger data.

"The temperature data launched an entire discipline called physical oceanography. It’s our first picture of the physical ocean all around the globe, and it remains a really important touchstone for looking back at the history of the climate,” says Josh Willis, a climate scientist at NASA who has used temperature data from Challenger in his research on global climate trends.

“Over 90 percent of the heat trapped by greenhouse gases is actually warming the ocean. Global warming is really ocean warming,” Willis explains. “Water is really good at absorbing heat, and most of the planet is covered in water.” And all that heat absorption comes at a cost: life in the ocean, especially coral, is already being harmed by climate change.

Andreia Salvador, curator of mollusks at the Natural History Museum in London, also notes the importance of the Challenger collections in light of climate change and habitat destruction. “We need to know what’s out there. We don’t live alone on this planet, and now more than ever, we need to conserve and preserve what’s there,” she says.

The naturalists on board Challenger couldn’t have fathomed all the ways their findings would be used today. That’s often the case with science — it’s an investment in a future that we can’t even imagine. “There are so many applications for the [ Challenger ] collections, and we still don’t even know the real possibilities,” says Salvador.

Scientists don’t necessarily know how their research will be used in the future, but they soldier on, motivated by an intrinsic drive to understand the world around them. It’s a sentiment reflected in a song written for Challenger ’s crew, documented by Matkin. He sent home the lyrics to his cousin: “Our mission is to teach the world what man ne’er knew before; all truth, by science is unfurl’d, which nature has in store.”

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HMS Challenger spent four years conducting scientific measurements around the world between 1872 and 1876. Image © The Trustees of the Natural History Museum, London (All Rights Reserved).

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HMS Challenger: How a 150-year-old expedition still influences scientific discoveries today

This year marks 150 years since the voyage of HMS Challenger  left on its mission of scientific discovery.

Museum researchers explain how the groundbreaking expedition is still important for scientists working today. 

Over a century ago, one of the most important scientific expeditions in history departed from the UK to explore the world's oceans.

When HMS Challenger left Portsmouth on 21 December 1872, the crew of scientists and sailors aboard had little idea what they would discover over the next four years. Though some would depart the expedition early, and others would never return, their voyage would discover thousands of species , locate the deepest trench on Earth , and even contribute to our knowledge of space .

As the Challenger expedition approaches its 150th anniversary, scientists are continuing to make new discoveries from the specimens collected by these Victorian pioneers. 

Dr Stephen Stukins , Senior Curator of Micropalaeontology at the Museum, says, ' Challenger  's voyage of discovery 150 years ago was very impressive for its time.'

'They had a lot of foresight, such as keeping ridiculous amounts of rope on board to measure the deepest parts of the ocean and collecting samples that we only began to unlock the science of over a century later.'

'I couldn't imagine an expedition being so well-funded today and taking such a holistic view of the oceans.'

In recognition of the expedition's ongoing importance, the Museum will be hosting the Challenger Society’s biennial conference on this 150 th anniversary, gathering scientists from across the UK and the world to discuss the latest research in oceanography – an entire scientific discipline kicked off by the voyage.

The Challenger expedition began as the result of lobbying efforts from the Royal Society for a global scientific voyage. Image © The Trustees of the Natural History Museum, London (All Rights Reserved).

From England to South Africa

At the start of the 1800s, the existence of life in the deep sea was a hotly contested area of debate. The French naturalist François Péron believed the seabed was permanently covered in ice, while Edward Forbes suggested the water pressure below 600 metres made life impossible. 

However, new methods for measuring the depth of the ocean and retrieving samples, known as sounding, showed that life could exist at great depths. This prompted the Royal Society to lobby the UK government for a global scientific expedition that would study all aspects of the oceans .

In response, HMS Challenger was provided by the Royal Navy in 1871. Most of the guns were removed to be replaced by scientific laboratories, deep-sea sampling equipment and dredging ropes over seven kilometres long.

After leaving for Gibraltar in 1872, the expedition got off to a few false starts as the crew accidentally broke some of the ship's dredging lines. However, they soon discovered one of their first new species - Umbellula thomsoni , a bioluminescent cnidarian related to jellyfish .

Throughout the voyage, over 4,700 new species would be described, including around 10% of all known starfish . As the voyage zigzagged across the biodiverse waters of the Atlantic on its journey south, many new species were collected such as the rare brachiopod Abyssothyris wyvillei .

This animal was found more than 4,800 metres below the surface, much deeper than scientists had expected, and was described as 'one of the three most interesting specimens' collected by the voyage.

Foraminifera collected by Challenger can help demonstrate the effect of climate change. Image © The Trustees of the Natural History Museum, London (All Rights Reserved).

This section of the voyage also saw many discoveries of plankton known as Radiolaria , of which over 2,000 new species would be discovered over the course of the voyage. Some of the species were named after the crew of the ship in the genera Challengeron and Protocystis (formerly Challengeria ).

Another group recorded in abundance were foraminifera , which use the alkaline mineral calcium carbonate to make their shells. Now, 150 years later, these same specimens have been used to investigate the impact of climate change on the oceans.

'At the time, the importance of these specimens to study the climate weren't appreciated,' Stephen explains. 'It wasn't until the 1960s that Sir Nicholas Shackleton would link foraminifera to ancient climate and ice ages, which have since been built on to investigate more recent climate change.'

'I was part of a study which compared plankton tow material from  Challenger  to that collected by a recent expedition. While the species composition was mostly the same between the expeditions, we found the thickness of their shells has thinned over the past 150 years.'

'It's not just one species, but every specimen and species we looked at. This thinning is due to ocean acidification as a result of increased carbon dioxide in the atmosphere.' 

The expedition documented and named new islands in the Southern Ocean around Kerguelen. Image © Wirestock Creators/Shutterstock

Exploration of the Southern Hemisphere and Australasia

Just over a year into its voyage, HMS Challenger left South Africa to journey across the Antarctic circle towards Australia and New Zealand .

Along the way, the ship visited and worked on isolated islands including Marion, Kerguelan and McDonald. The crew discovered new islands, as well as a range of unique species such as a moss now known as Dicranoweisia insularis . 

The next port of call for Challenger was Australia  in March 1874, where the scientists received specimens of the thylacine , otherwise known as the Tasmanian tiger. With the last known individual dying in 1936, the anatomical studies conducted of these animals are still some of the most detailed of this extinct species.

Between being entertained by the country's officials, the scientists journeyed inland to investigate more of the continent's flora and fauna. Some of their methods, such as dynamite fishing, would never be used by modern scientists.

Challenger 's time throughout Australasia is also marred by their attitudes towards the area's Indigenous peoples. While there was some collaboration with Indigenous communities on collecting, not all of the crew's interactions were as positive. Accounts of the voyage also use outdated language and ideas that are considered racist and unacceptable.

After visiting New Zealand, the expedition headed past Fiji and up to Hong Kong, where the ship's captain, Captain Nares, was replaced by Captain Thomson on 2 January 1875. The new commanding officer took the ship past the Philippines , where the expedition surveyed the newly formed volcano Mount Vulcan.

The expedition then headed down to New Guinea and the Admiralty Islands, but as this took longer than expected Challenger was forced to abandon attempts to visit Pacific islands such as Guam and instead head straight for Japan .

This proved fortunate, allowing the expedition to make a landmark discovery. While taking a depth sounding, Challenger discovered the Mariana trench, the deepest point on Earth, and recorded a depth of over 8,200 metres. 

More modern measurements put the trench's lowest point, named Challenger Deep in honour of the expedition, at roughly 11,000 metres. Many of the ship's soundings still form the basis of seabed maps today, with its findings comprising the basis of modern oceanography.

Dr. Rudolf von Willemoes-Suhm (centre) died during the voyage, while Prof. Charles Wyville Thomson (right) died before the all of the  Challenger reports were published. Image © The Trustees of the Natural History Museum, London (All Rights Reserved).

The voyage home

Following a stopover in Japan for repairs in April 1875, HMS Challenger set out across the Pacific Ocean for Hawaii . While dredging the ocean floor, they began to collect lumps of metal around the size of large potatoes known as polymetallic nodules .

Museum scientist Professor Richard Herrington says, 'These were the first polymetallic nodules ever discovered, and as they were found in a few locations across the Pacific, this made them even more interesting to scientists.'

'The nodules were cut open, and it was recognised they had nucleated around shark teeth and even a sponge. While the nodules were appreciated for their scientific curiosity, their preservation of animal remains was also of interest.'

'While their mineral value was thought to be limited at the time, they are today potential targets for seabed mining .'

On arriving in Hawaii, the  Challenger  expedition also noted another modern concern - the issue of invasive species :

'American plants are covering the ground, and American birds have been introduced and bid fair to spread and oust the native fauna, which has no single land bird in common with any other Polynesian island group.'

Since this account was written, invasive species introduced by both Americans and Europeans have contributed to a wave of extinctions across Hawaii. The Hawaiian Biological Survey estimates at least 271 species have gone extinct in the past 200 years, with the US proposing nine more species from the island be considered extinct last year.

The disappearance of wildlife was not the only loss  Challenger  witnessed in the Pacific. One of the expedition's scientists, Dr Rudolf von Willemoes Suhm, died of an infection on route to Tahiti . In his honour, a genus of crustaceans,  Willemoesia , as was Suhm island near Kerguelen.

Ocean bottom sediment collected by Challenger can have micrometeorites extracted from it. Image © The Trustees of the Natural History Museum, London (All Rights Reserved).

However, it wasn't all bad news - some of the voyage's Pacific discoveries were out of this world.

' Challenger  is important because it's the first time micrometeorites were ever collected,' says Dr Natasha Almeida , the Museum's meteorite curator. 'These objects are below a millimetre in size and come from several sources, such as comets and asteroids.'

'It's remarkable they had the foresight to consider micrometeorites would collect at the bottom of the ocean and they could separate them from dredged material using magnets. As far as I'm aware, it's the oldest collection of micrometeorites in the world by at least 100 years, if not more.'

After sailing down the coast of South America , the ship crossed back across the Atlantic to Ascension Island and then back to England. After four years, the voyage had returned home. 

Anatomical studies performed on a male and female thylacine remain some of the most detailed of the extinct species. Image © The Trustees of the Natural History Museum, London (All Rights Reserved).

The legacy of Challenger

Across Challenger 's long voyage, specimens had been periodically packed up and sent back to the UK, where they were stored at the University of Edinburgh . Remarkably, only three bottles arrived broken from among thousands of samples shipped halfway around the world.

The specimens were then sent to the leading scientists of the day in their field, with extensive reports compiled over the next decade. Eventually, the type specimens, which are the named representatives of a species, were sent to the Museum while duplicate specimens were split across other institutions.

Even 150 years later, these specimens are still important for research. Stephen, for instance, is hoping to make use of samples from other collections to assess how foraminifera are being affected by climate change in greater detail.

'Comparing Challenger material to that from other expeditions, such as the Discovery cruise , would allow us to map these changes in more detail, and may allow us to predict how these species could change in the future,' Stephen says. 'This could also involve taking a closer look at how acidification has changed in the past 150 years.'

The collections are also continuing to reveal new specimens, with Natasha part of a team of scientists extracting more micrometeorites from the ocean bottom deposit collection .

'At the time, micrometeorites were very difficult to study, but the development of new technologies allows us to do much more with them,' Natasha explains. 'Extracting new samples can allow us to compare how the number of micrometeorites hitting each part of the world varies.'

'We're hoping to compare these new micrometeorites from the Challenger material with modern specimens from Antarctica which are more pristine because it's so dry there. We hope this will allow us to come up with a weathering scale for ocean-collected micrometeorites.'

'Researching such small samples can also help us prepare to study small samples from asteroid return missions, such as Hayabusa2 and OSIRIS-REx .'

The first polymetallic nodules were discovered by HMS Challenger in the Pacific Ocean. Image © The Trustees of the Natural History Museum, London (All Rights Reserved).

The samples are also informing important decisions that will shape the future of our planet's ecosystems and our economies.

'Since the 1870s, the polymetallic nodules collected by  Challenger  have been appreciated as a possible source of rare metals,' Richard says. 'They act as the type specimens of these structures.'

'There are real challenges to extract the necessary metals for a green revolution from the resources found on land, so minerals on the seabed are an obvious place to investigate.

'However, we still don't have enough information about what the effects of seabed mining will be which is why Museum scientists are continuing to investigate the biodiversity of the nodule fields.'

' Challenger  specimens are part of the data being used to consider the benefits, as well as the impacts, of any mining operations.'

As the deep sea continues to be explored, more scientific discoveries will be made that tell us more about our world's past, present and future. Much of it will continue the work of  HMS Challenger , the impact of which continues to shape scientific thought today.

• Museum history
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Find out more about why we need to protect the oceans, find themed events, and read about the pioneering work of the Museum's marine scientists.

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Pacific expedition may have discovered over 30 new deep sea species

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Explorer-filmmaker James Cameron emerges from his sub after returning from Challenger Deep.

James Cameron on Earth's Deepest Spot: Desolate, Lunar-Like

Trip to Challenger Deep felt as if he'd "gone to another planet."

The Mariana Trench 's Challenger Deep—the deepest point on Earth—looks as bleak and barren as the moon, according to James Cameron , who successfully returned just hours ago from the first solo dive to the ocean abyss.

At noon, local time Monday (10 p.m. ET Sunday), the National Geographic explorer and filmmaker's "vertical torpedo" sub broke the surface of the western Pacific, some 200 miles (322 kilometers) southwest of Guam.

( Video: James Cameron Breaks Solo Dive Record. )

After a descent that took roughly two and a half hours, Cameron spent about three hours conducting the first manned scientific exploration of Challenger Deep.

For his return trip, Cameron experienced a faster-than-expected, roughly 70-minute ascent, which he described as a "heckuva ride."

Bobbing in the open ocean, his custom-designed sub, the DEEPSEA CHALLENGER, was spotted by helicopter and plucked from the Pacific by a research ship's crane.

The expedition was designed so that Cameron could spend up to six hours collecting samples and video at the bottom of the trench. But his mission was cut short due in part to a hydraulic fluid leak that coated the window of the sub's "pilot sphere," obscuring his view.

"I lost hydraulics toward the latter part of dive, and I was unable to use the manipulator arm," Cameron said this morning during a post-dive press conference held aboard the Octopus, a yacht owned by Microsoft co-founder Paul Allen , a longtime Cameron friend. (Allen was on the scene for the historic dive and posted live updates of the event on Twitter from aboard his yacht, which provided backup support for the mission.)

Considering the daunting task of sending humans into the deep, such technical glitches are to be expected, Cameron emphasized: "It's a prototype vehicle, so it's gonna take time to iron out the bugs.

"The important thing is that we have a vehicle that's a robust platform—it gets us there safely, the lights work, the cameras work, and hopefully next time the hydraulics will work."

And although he wasn't able to capture as many samples on this first dive as science teams might have been hoping for, "that just means I gotta go back and get some more," said Cameron, also a National Geographic Society explorer-in-residence .

In fact, he and sub co-designer Ron Allum, managing director of the Australia-based Acheron Project research and design company, already have more dives planned in the coming weeks as part of the DEEPSEA CHALLENGE project , a partnership with the National Geographic Society and Rolex. (The Society owns National Geographic News.)

"I see this as the beginning ... of opening up this frontier to science and really understanding these deep places," Cameron said.

Little Life Found in Challenger Deep

Aboard the DEEPSEA CHALLENGER, Cameron had a host of tools at his disposal, including a sediment sampler, a robotic claw, and temperature, salinity, and pressure gauges. (See pictures of Cameron's sub .)

The sub is also outfitted with multiple 3-D cameras and an 8-foot (2.5-meter) tower of LEDs.

But in part due to the hydraulics leak and a host of lost thrusters, Cameron wasn't able to capture any biological samples, and an attempted sediment core sample was only partially retrieved.

"I didn't see big jellyfish and big anemones like I saw [during test dives] at the New Britain Trench," off Papua New Guinea , Cameron said. (See "Giant 'Amoebas' Found in Deepest Place on Earth." )

At Challenger Deep "I landed on a very soft, almost gelatinous flat plain. Once I got my bearings, I drove across it for quite a distance ... and finally worked my way up the slope."

The whole time, Cameron said, he didn't see any fish, or any living creatures more than an inch (2.5 centimeters) long: "The only free swimmers I saw were small amphipods"—shrimplike bottom-feeders that appear to be common across most marine environments.

"When I was in the New Britain Trench a couple weeks ago, the bottom was covered in the tracks of small animals, which gave it an eggshell appearance," he added.

"But when I came to Challenger Deep, the bottom was completely featureless. I had this idea that life would adapt to the deep ... but I don't think we're seeing that."

Still, the science team is hopeful that the small sample Cameron took of the trench's sediments, along with the sub's constantly whirring cameras, will provide some new insight into the remote underwater realm. ( Video: How sound revealed that Challenger Deep is the deepest spot in the ocean. )

"Jim recovered about 50 milliliters of muddy seawater that I gleefully processed for culturing and for genomic studies," Doug Bartlett , chief scientist for the   DEEPSEA CHALLENGE project, said in an email to National Geographic News.

"Can't wait to see what new critters (Bacteria, Archaea, and fungi) that we discover," said Bartlett, a marine biologist at the Scripps Institution of Oceanography in San Diego, California.

The mud could contain exotic species of microbial life that may not only advance our understanding of the deep ocean but also help in the search for extraterrestrial life.

For instance, scientists think Jupiter's moon Europa could harbor a global ocean beneath its thick shell of ice—an ocean that, like Challenger Deep, would be lightless, near freezing, and home to areas of intense pressure. (See "Could Jupiter Moon Harbor Fish-Size Life?" )

Deep Dive was Like a Trip to Another Planet

Until Cameron's dive, the only manned Challenger Deep expedition was a mission that took place in 1960, when retired U.S. Navy Capt. Don Walsh and late Swiss engineer Jacques Piccard descended in the Navy submersible Trieste.

Climbing into the cockpit of DEEPSEA CHALLENGER, Cameron said he was "intimately aware of the design of the vehicle ... and I felt we'd done the engineering right.

"When the hatch closed, I felt the vehicle around me was able to withstand the pressure. There may be butterflies in your stomach beforehand, but once you're inside the sub, the excitement of going someplace [few have] been before takes over ... the adrenaline takes over, and the fear really goes away."

Cameron also had to overcome the sheer physical experience of the dive—the 57-year-old explorer was crammed into the sub's 43-inch-wide (109-centimeter-wide) pilot sphere, which itself was loaded up with navigation controls, cameras, and other electronics.

"I wind up packed in like a Mercury astronaut, if you will," Cameron said. ( Video: how the sub sphere protects Cameron. )

"When you first close the hatch, all these electronics are dumping heat into the sphere." Since the Mariana Trench lies near the Equator, surface temperatures are high, and the inside of the sub's cockpit "gets very hot right away—it's like a sauna inside.

"But as you start descending, the sub goes very fast. I'm screaming down, and in just a few minutes I'm in water that's 36 degrees Fahrenheit [2.2 degrees Celsius].

"All of sudden my feet are freezing, the back of my head is freezing, but the middle part of my body is still warm," he said.

Then, "literally within a minute or two I'm out of sunlight, and you're in total darkness for most of this dive, so the sub gets very cold, and you have to put on warm clothing. ... The walls have condensation all over them and I'm constantly getting dripped on by cold water."

Despite the physical challenges, Cameron seemed in awe of what he'd experienced in the remote ocean depths.

"This is a vast frontier down there that's going to take us a while to understand," he said. "The impression to me was it's very lunar, very isolated. I felt as if, in the space of one day, I'd gone to another planet and come back."

Hoping for Gifts From the Ocean

According to biological oceanographer Lisa Levin, of the Scripps Institution of Oceanography in San Diego, California, the DEEPSEA CHALLENGE program's potential for generating public interest in deep-ocean science is just as important as anything Cameron might have discovered.

"I consider Cameron to be doing for the trenches what Jacques Cousteau did for the ocean many decades ago," Levin, who's part of the team but didn't participate in the seagoing expedition, said in a previous interview with National Geographic News.

At a time of fast-shrinking funds for undersea research, Levin said, "what scientists need is the public support to be able to continue exploration and research of the deep ocean."

( Video: Cameron Dive First Attempt in Over 50 Years. )

Perhaps referring to his friend's most recent movie, expedition physician Joe MacInnis called Cameron a real-world "avatar."

Cameron was "down there on behalf of everybody else on this planet," MacInnis said. "There are seven billion people who can't go, and he can. And he's aware of that."

Camron added, "Every time you dive, you hope you'll see something new—some new species. Sometimes the ocean gives you a gift, sometimes it doesn't.

"But I call this dive just the first phase. We prove that the vehicle works, and hopefully bring some real science back."

Ker Than and Rachael Jackson, of National Geographic Channels International, contributed reporting to this story.

Additional major support for the DEEPSEA CHALLENGE expedition was provided by the Alfred P. Sloan Foundation.

Related Topics

• SCUBA DIVING

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Challenging the Deep

A voyage of discovery.

• A Ship for Science
• The Science of Illustration
• The Challenge Continues
• Our Oceans' Future

HMS Challenger ’s mission, as laid out by the Royal Society, was four-fold: to investigate the physical conditions of the deep sea in the great ocean basins; to determine the chemical composition of seawater at various depths from the surface to the bottom; to ascertain the physical and chemical character of deep-sea deposits and their sources; and to investigate the distribution of organic life at different depths and on the sea floor. In these endeavors the scientists aboard – with the aid of the Royal Navy’s labor – succeeded admirably, to the limits of their equipment. To this day oceanographic missions continue to expand on the revelations of Challenger , trawling the deep for knowledge of the seas.

Challenger’s voyage took her around the globe, from the modern ports of Europe and Asia to tiny barely charted islands and almost within sight of Antarctica. Along the way her crew took 492 deep sea soundings (dropping a measured rope to determine depth), dredged the bottom in 133 places, sampled water temperature and composition 263 times, and discovered roughly 4,700 new marine species. Perhaps their most famous discovery was the Challenger Deep, an area near Guam at the southern end of the Mariana Trench which is now known as the deepest place on the planet. Challenger ’s sounding there was almost 27,000 feet; subsequent missions have confirmed portions of the Deep to be over 35,000 feet below the surface.

Challenger called on many ports that were unusual to Englishmen of the time, and her scientific crew used the opportunities to add to their knowledge. At Hawaii, a team from the ship ascended Kilauea, taking a photograph of the active volcanic crater. During rest and refitting in Australia, several of Challenger ’s naturalists took time to observe and sketch local fauna in their native habitats, including koalas and platypuses.

Home » Records » Deepest Part of the Ocean » Bathyscaphe Trieste

First Trip to the Deepest Part of the Ocean

The bathyscaphe trieste carried two hydronauts to the challenger deep in 1960.

Bathyscaphe Trieste: The Bathyscaphe Trieste lifted out of the water, circa 1958-59. U.S. Naval Historical Center Photograph.

On January 23, 1960, Jacques Piccard and Don Walsh boarded the Bathyscaphe Trieste sea vessel and descended to the deepest part of the ocean: The Challenger Deep in the Mariana Trench .

Where is the Mariana Trench? The Mariana Trench is located in the western Pacific Ocean. It was discovered to be 10,924 meters deep in 1951 by researchers aboard the British survey ship Challenger. Trieste was the first vehicle to explore the trench with a crew of two people. Map by Geology.com and MapResources.

The Ship: The Bathyscaphe Trieste

A bathyscaphe (pronounced BA-thi-skaf; meaning: "deep ship") is a submersible vessel with a spherical room for research and observation. This observation chamber is attached to the bottom of a tank filled with gasoline. Gasoline is more buoyant than water and is highly resistant to compression, which makes it well-suited for the high pressure of deep-sea dives.

Trieste (pronounced TREE-est-a) was the name given to the bathyscaphe that would make history by traveling into the Challenger Deep on January 23, 1960. It was named after the city in which it was built, on the border between Italy and Yugoslavia. The Trieste carried hydronauts Don Walsh and Jacques Piccard approximately 11,000 meters underwater - that is, about 11 kilometers (or 7 miles) into the deepest part of the Pacific Ocean.

The ship's instruments initially registered the vessel's depth to be 11,521 meters, but this was later recalculated to 10,916 meters. More recent measurements indicate the bottom of the Challenger Deep to be roughly 11,000 meters below sea level.

Mariana Trench Cross-Section: The Mariana Trench is the boundary between two tectonic plates: the Pacific Plate and the Mariana Plate. Image by NOAA.

The Deepest Part of the Ocean: Challenger Deep

The lowest point on the surface of the Earth's crust is underwater, in the western North Pacific Ocean. There is a convergent plate boundary where the Pacific Plate is being forced down into the mantle beneath the Mariana Plate. At this type of plate boundary, an elongated depression called a "trench" is formed - in this case, it is the Mariana Trench. (See map and illustration.)

Within the Mariana Trench, there is a small valley that goes even farther into the Earth's crust - this spot, called the Challenger Deep, is the deepest part of the ocean. The distance between the ocean's surface and the bottom of the Challenger Deep (11,000 meters) is greater than the height of Mount Everest (8,850 meters). That means if you were to put the world's highest mountain inside the deepest part of the ocean, the mountain's peak would still be more than 2 kilometers underwater!

Don Walsh and Jacques Piccard: Lieutenant Don Walsh, USN, and Jacques Piccard in the bathyscaphe TRIESTE. Location: Mariana Trench, 1960. NOAA Ship Collection.

The Explorers: Don Walsh and Jacques Piccard

Oceanographer Jacques Piccard (1922-2008) worked with his father Auguste to design the Trieste. Auguste Piccard, a scientist from Switzerland, had experimented with buoyancy methods for his balloon flights - in fact, he broke the record for the highest altitude balloon flight in 1931-1932. He applied this knowledge about buoyancy to design the Trieste. So, interestingly, at one point in time the Piccard family held the record for both the highest altitude balloon flight and the deepest ocean dive.

Oceanographer Don Walsh (1931-2023), a Lieutenant of the United States Navy, was the other explorer in the Bathyscaphe Trieste's small pressure sphere. He spent over 50 years in oceanic research, and is celebrated by Life magazine as one of the world's great explorers.

The descent into the Challenger Deep took nearly five hours. Once the Bathyscaphe Trieste reached the sea floor, Walsh and Piccard observed their surroundings. The ship's light allowed them to see what they described as a dark brown "diatomaceous ooze" covering the sea floor, along with shrimp and some fish that appeared to resemble flounder and sole. Since the Plexiglas viewing window had cracked during the descent, the men were only able to spend about twenty minutes on the sea floor. Then, they unloaded the ballasts (nine tons of iron pellets, and tanks filled with water) and began to float back to the ocean's surface. The ascent was much quicker than the dive, taking only three hours and fifteen minutes.

For over 50 years, Jacques Piccard and Don Walsh were the only people who had ever seen the deepest part of the ocean firsthand.

Since this monumental voyage, unmanned, remotely operated crafts have ventured into the Challenger Deep - such as Kaiko in the late 1990s, and Nereus in 2009. No other human beings had traveled to the bottom of the Mariana Trench until 2012, when Canadian film director James Cameron made history as the first person to make a solo trip to the Challenger Deep in the Deepsea Challenger . Then in 2019, American explorer Victor Vescovo descended to a record 10,928 meters in the Limiting Factor . He was the first person to make the dive more than once.

There will surely be more manned expeditions in the future. However, there will always be a special place in history for the two men who were brave enough to risk their lives back in 1960 and prove that the trip was possible.

Find Other Topics on Geology.com:

The Challenger Expedition research guide

A guide to the collections of Royal Museums Greenwich

This research guide provides an overview of items in the collection of Royal Museums Greenwich relating to the history of the Challenger Expedition, which circumnavigated the world between 1872 and 1876.

The Challenger Expedition was the first to explore the deep sea on a global scale. It took its name from the Royal Navy vessel that was specially converted for this scientific work .

The expedition was integral to the advance of oceanography as a modern scientific discipline and is still influencing our understanding of the ocean as a complex ecosystem upon which all life depends today.

You can read our Challenger webpages for more information about the circumnavigation and its oceanographic work. Researchers interested in understanding the Challenger Expedition within the broader history of the Royal Navy in the nineteenth century are also encouraged to consult our Royal Navy research guides .

Explore the guide online below, or download the PDF version .

How is this guide organised?

Published sources (a-z by author), archival documents and manuscripts.

• Charts and maps

Visual and photographic sources

Challenger ship plans, secondary sources in the caird library.

• Materials beyond Royal Museums Greenwich's collections

This research guide covers published primary source materials, unpublished archival documents including manuscripts, charts and maps, visual and photographic sources, and objects related to the Challenger Expedition held within Royal Museums Greenwich's collections. The final section summarises secondary historical research on the expedition that can be found in the Caird Library .

Within each section, materials are organised alphabetically according to the author or creator of the work. An appendix at the end of the guide points researchers to Challenger -related materials beyond Royal Museums Greenwich.

Researchers can find Library and Archive catalogues as well as information on visiting and ordering materials to the Caird Library on the Caird Library and Archive website .

The predominant source for the historical and biographical information contained within this research guide is Erika Jones’s book The Challenger Expedition: Exploring the Ocean’s Depths .

Who is represented in this research guide and why?

The Challenger Expedition was shaped by Britain’s existing empire and its colonial ambitions. As such, the archival record of the expedition held by Royal Museums Greenwich is largely written from the viewpoint of its European crewmembers and naturalists.

The crew made contact with Indigenous peoples in places including Fiji, Hawai’i, and Tonga, to name just a few examples in the Pacific Ocean. Researchers should be aware that when materials relating to these peoples feature in the archive, written descriptions and photographic representations can be outdated and offensive.  

The youngest son of the 8th Duke of Argyll, Lord George Campbell served on the Challenger Expedition as Sub-lieutenant. He left the expedition in Chile, having been promoted. His letters “were written home during our cruise with no intention of publication […] Such as they are I hope they will give the reader a general idea of the Challenger’s cruise – a cruise which will rank as famous in the Annals of science”.

Henry Nottidge Moseley served on the Challenger Expedition as a naturalist. He had previously studied medicine. Moseley researched botanical and animal specimens, but was also involved in acquiring Ancestral remains of Indigenous people for ethnographic study. Moseley contributed the Report on Certain Hydroid, Alcyonarian, and Madreporarian Corals to the final Challenger Report.

John Murray served on the Challenger Expedition as a naturalist. Born in Canada in 1841 to Scottish parents, as a young man hemoved to Britain to live with his grandfather and studied at the University of Edinburgh. He gained experience analysing marine specimens and ocean currents as a ship’s surgeon on the whaling ship Jan Mayen and was later selected to work as a naturalist on board Challenger .

Following the death of Charles Wyville Thomson in 1882, Murray was appointed the Director of the Challenger Office and was responsible for the publication of most of the volumes of the Challenger Report . He co-authored the Report on Deep-Sea Deposits with Belgian geologist Alphonse-Françoise Renard.

The Report on Deep-Sea Deposits is the penultimate volume of the multi-authored Challenger Report, whose 50 volumes were published between 1880 and 1895. Murray and Renard’s work on deep-sea deposits contains some of the most significant and enduring findings from the expedition, including a colour-coded chart that visualises the global distribution of deep-sea sediments, which combined the data collected during the Challenger Expedition with those gathered on later voyages. Murray continued his work as a leading international researcher in the fields of oceanography and marine biology until his death in 1914.

William James Joseph Spry served on the Challenger Expedition as the Chief Engineer.

Herbert Swire served on the Challenger Expedition as Navigating Sub-Lieutenant until it reached South America in 1876 . Born in Staffordshire in 1850, he entered the Royal Navy as a cadet in 1864. Challenger ’s deepest sounding, at just over 8,200m (around 27,000 feet), was originally named the Swire Deep and it was the greatest known ocean depth at the time. Swire was the last remaining survivor of the crew when he died in 1934.  

Charles Wyville Thomson led the scientific crew onboard HMS Challenger . Although he graduated from the University of Edinburgh with a degree in medicine, he also took classes in botany, and later worked as Professor of Botany at both the University of Aberdeen and the Royal College of Science, Dublin. Following the successes of his deep-sea dredging expeditions on HMS Lightning (1868) and HMS Porcupine (1869), which showed that marine life existed as deep as 650 fathoms (1188m), he was appointed the Director of the Scientific Civilian Staff on HMS Challenger.

John James Wild served on the Challenger Expedition as official artist and personal secretary to Charles Wyville Thomson. He was born in Zurich, Switzerland in 1824 and was a naturalist, linguist, and scientific illustrator. His illustrations include places and people that the expedition encountered, as well as records of the oceanographic equipment used on board and visual charts created from bathymetric data collected during the voyage.

John Hynes served on the Challenger Expedition as Assistant Paymaster. Royal Museums Greenwich holds a journal and three photograph albums made by Hynes that document the circumnavigation.

John Fiot Lee Pearse Maclear served on the Challenger Expedition as commander under Captain Sir George Nares. He was born in Cape Town in 1838 and entered the Navy. Maclear was promoted to captain after the completion of the expedition in 1876.

Abraham Smith had an active life in the Royal Navy, seeing service both in war (on board the Ratter in the Anglo-Satsuma War (1863), in which he was shipwrecked) and peace time. A large part of his memoir is devoted to his service on the Challenger Expedition.

The Tizard collection

Thomas Henry Tizard served on the Challenger Expedition as Navigating Officer and Assistant Surveyor from 1872, and was promoted to Staff Commander in 1874. He was a surveyor and navigator in the hydrographic service of the Navy. Tizard remained on board HMS Challenger after Nares left from Hong Kong to take command of the Arctic Expedition in 1875. When the Challenger Expedition ended, Tizard, alongside John Murray, was responsible for writing the narrative of the voyage with its hydrographic and oceanographic results.

The Tizard collection consists of logbooks, diaries, official and private letters, and charts.

Charts and Maps

*Sir George Strong Nares served on the Challenger Expedition as its Captain until 1875, when he was summoned to take charge of the British Arctic Expedition.  

The sketches and photographs in the collections of Royal Museums Greenwich capture harbours, vistas, geological features, flora and fauna that the expedition’s crew encountered and desired to record.

The voyage is considered one of the first global scientific expeditions to embrace photography in an official capacity. In the context of British imperialism, sketching and photography recorded buildings, terrestrial features, fortifications, harbours and roads of interest to the government, its military and commerce.

The photograph albums also include images of coastal communities and Indigenous peoples, including Fiji, O’ahu (Hawai’i), and Tongatapu (Tonga) to name some examples from the Pacific. Some of these photographs were composed as part of ethnographic studies, and used to support now debunked theories of white supremacy. The photographic collection offers little information about the individuals it depicts, but it provides an insight – from the perspective of the white European scientists – into the communities with which the Challenger Expedition came into contact.

The photograph albums also contain images of Challenger ’s Sub-Lieutenants, the lowest-ranked commissioned officers on the ship, and groups of sailors, providing glimpses of the contribution of a group of men whose experiences have not been preserved elsewhere.

John Hynes ’s photographic albums follow a long tradition of naval album-making and storytelling. After the expedition, Hynes assembled 371 photographs into these three albums, which present the circumnavigation in roughly chronological order and are incorporated into a longer narrative of Hynes’s life.

Royal Museums Greenwich holds a number of Challenger ship plans, which shed light on how the refit of the naval vessel worked to make space for science at sea .

The ship plans collection, held at the Museum’s Brass Foundry site in Woolwich, includes plans for the sails as fitted for the ‘special service’ (NPA8449 and NPD3895), the hold (NPA8448), the main, upper and lower decks, and the profile showing inboard details (NPC7357).

Joseph Matkin served as a ship’s steward’s assistant on the Challenger Expedition for the full duration of the voyage. He was born in Uppingham, Rutland in 1853. He entered the merchant marine in 1867 and the Royal Navy in 1870. Matkin sent home letters which he composed from his journal. He commented on oceanographic activities, life on board the ship and on the history, geography and people of the ports at which the ship called. The original letters are kept at the Special Collections & Archives, UC San Diego .

Challenger Expedition materials beyond Royal Museums Greenwich

Edinburgh University Library, Centre for Research Collections - The University’s archive of Challenger materials includes lithographs, engravings, photographs, and statistical and cartographical materials. The collection also contains pencil, ink and watercolour illustrations of marine life, rock and crystal formations, and several small scenic paintings.

Museum of Comparative Zoology, Ernst Mayr Library, Cambridge, MA - The Museum of Comparative Zoology (MCZ) at Harvard University cares for 225 zoological specimens from the HMS Challenger voyage. The Museum’s library and archive holds a number of printed published materials from the expedition, as well as annotated copies by important figures in the history of science such as Theodore Lyman and Elizabeth Hodges Clark, assistant to Alexander Agassiz.

National Library of Scotland, Archives and Manuscripts Collection, Edinburgh - As a legal deposit the National Library of Scotland has collected the majority of the published output from the Challenger Expedition including the extensive scientific reports series, books by individual members of the expedition, newspaper articles and letters, and even lectures. They also hold the archive of publisher John Bartholomew & Son who created the maps for the reports. Proof copies of the maps are available. The draft and notes of Erik Linklater’s popular account of the expedition ‘The Voyage of the Challenger’, is available, as well as its numerous published editions.

National Museum of the Royal Navy, UK - The NMRN has a small but important collection relating to Challenger , including an album of 409 photographs taken during the expedition and a commemorative medallion awarded to Engineer Alfred J. Allen.

National Museums Scotland, Edinburgh – National Museums Scotland cares for over 1,000 specimens from the Challenger voyage. These include birds and bird eggs, foraminifera, diatoms, echinoderms, sponges, and even some butterflies. The majority of the specimens from the voyage were sent to the Natural History Museum but Thomson proposed that a duplicate set of specimens should be located in the Edinburgh museum. NMS also holds duplicate and original images from the voyage.

Natural History Museum, Library and Archives, London – The Natural History Museum cares for 10,000 examples of material from the voyage, including birds, worms, fish, molluscs, insects, mammals and foraminifera. The Museum’s Ocean Bottom Deposit collection includes thousands of samples taken during the Challenger Expedition. They also hold a substantial amount of archival material, including letters and photographs from and referring to the Challenger Expedition.

UK Hydrographic Office Archive, Taunton, Somerset - The UKHO holds numerous observations and repots on ocean soundings and temperatures from across the globe, sailing directions, and correspondence from the Challenger voyage. In addition to this are other supporting records, such as letter books, minute books, files, and service records that contain information about the voyage and the Royal Navy personnel involved with it.

Find more resources and collections

Explore the collection

Main image: Illustration of the analysing room on the main deck of HMS Challenger ( ALB0174 )

Esri Releases New Book on Dr. Dawn Wright's Historic Challenger Deep Dive

Mapping the Deep: Innovation, Exploration & the Dive of a Lifetime Explores the Importance of Mapping the Ocean

REDLANDS, Calif.—September 4, 2024— Esri, the global leader in location intelligence, today announced the publication of Mapping the Deep: Innovation, Exploration & the Dive of a Lifetime .

The new book by oceanographer Dr. Dawn Wright details the historic 2022 trip that made her the first Black person to visit Challenger Deep in the Mariana Trench, the deepest and most unexplored place on earth—over 10,000 meters beneath the Pacific Ocean’s surface.

We currently know less about the ocean floor than about the surface of the moon. Just one-fourth of the seabed has been mapped in high resolution to date, and as an ocean scientist and explorer, Wright has made it her mission to change that.

With a foreword by marine geologist Kathryn Sullivan, the first American woman to walk in space, Mapping the Deep takes readers on an adventure that showcases the perseverance and innovation required for ocean exploration. With a focus on Wright’s historic dive, her personal journey, and the cutting-edge technology that made the expedition possible, the book highlights the crucial importance of mapping the ocean and its profound impact on the planet’s future. From the fascinating history of Challenger Deep and its explorers to the diverse marine life that resides within, Mapping the Deep is a blend of history, fascinating facts, and beautiful images.

As chief scientist of Esri, Dr. Dawn Wright aids in strengthening the scientific foundation for Esri software and services while also representing Esri to the scientific community. A specialist in marine geology, with record-setting submersible dives in Alvin (to the East Pacific Rise), Pisces V , and Limiting Factor (to Challenger Deep), she has also authored and contributed to some of the most definitive literature on marine GIS.

Mapping the Deep is available in paperback (ISBN: 9781589487888, US$26.99) and as an ebook (ISBN: 9781589487895, US$26.99). This book can be obtained from most online retailers worldwide. Interested retailers can contact Esri Press book distributor Ingram Publisher Services.

Esri, the global market leader in geographic information system (GIS) software, location intelligence, and mapping, helps customers unlock the full potential of data to improve operational and business results. Founded in 1969 in Redlands, California, USA, Esri software is deployed in hundreds of thousands of organizations globally, including Fortune 500 companies, government agencies, nonprofit institutions, and universities. Esri has regional offices, international distributors, and partners providing local support in over 100 countries on six continents. With its pioneering commitment to geospatial technology and analytics, Esri engineers the most innovative solutions that leverage a geographic approach to solving some of the world’s most complex problems by placing them in the crucial context of location. Visit us at esri.com .

Copyright © 2024 Esri. All rights reserved. Esri, the Esri Globe and Frame logos, The Science of Where, esri.com, and @esri.com are trademarks, service marks, or registered marks of Esri in the United States, the European Community, or certain other jurisdictions. Other companies and products or services mentioned herein may be trademarks, service marks, or registered marks of their respective mark owners.

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• Ocean Exploration Facts

How deep is the ocean?

The average depth of the ocean is 3,682 meters, or 12,080 feet..

Remotely operated vehicle Deep Discoverer surveys an interesting geological feature during the final dive of the Windows to the Deep 2018 expedition. Image courtesy of NOAA Office of Ocean Exploration and Research. Download image (jpg, 36 KB) .

Overall, the ocean is pretty deep; however, its bottom is not flat or uniform, which means water depths in the ocean also vary. The deepest place in the ocean measures 10,935 meters (35,876 feet) and is found in the Pacific Ocean’s Mariana Trench, at a place called Challenger Deep.

The most-recent estimate of the average ocean depth of 3,682 meters (12,080 feet) was calculated in 2010 by scientists from NOAA and Woods Hole Oceanographic Institution using satellite measurements. These measurements revealed that the seafloor is much bumpier and mountainous than previously known and resulted in an average ocean depth that is less than previously calculated.

While satellite measurements have yielded better estimates of ocean depth than we have had in the past, rather than measuring the seafloor itself, satellites actually look at the sea surface and detect changes over features like a mountain on the seafloor. So the picture of the seafloor scientists get is far from perfect and is not a very good resolution.

High-resolution seafloor mapping, such as that conducted on NOAA Ship Okeanos Explorer, is needed to fine tune the satellite data. We have only mapped about 26 percent of the Earth’s seafloor in high resolution  as of June 2024, meaning that estimates of average ocean depth remain just that: Estimates.

For More Information

In the Shadow of the Mariana Trench - 2016 Deepwater Exploration of the Marianas

Leg 3: A Geological Tour of the Northern Marianas - 2016 Deepwater Exploration of the Marianas

WHOI Study Calculates Volume and Depth of the World’s Oceans  - Woods Hole Oceanographic Institution 

Mariana Arc - Submarine Ring of Fire 2004

• RISKS AND DANGER
• JAMES CAMERON
• TRIBUTE TO ANDREW & MIKE
• ROLEX DEEP-SEA HISTORY
• THE MARIANA TRENCH
• WHAT’S NEXT
• PILOT SPHERE
• SYSTEMS AND TECHNOLOGY
• THEN AND NOW
• MICROBIOLOGY
• MARIANAS TRENCH MARINE NATIONAL MONUMENT
• LATEST NEWS
• EXPEDITION JOURNAL
• FOR EDUCATORS

THE EXPEDITION

” I’ve always dreamed of diving to the deepest place in the oceans. For me it went from a boyhood fantasy to a real quest, like climbing Everest, as I learned more about deep-ocean exploration and became an explorer myself in real life. This quest was not driven by the need to set records, but by the same force that drives all science and exploration … curiosity. So little is known about these deep places that I knew I would see things no human has ever seen. There is currently no submersible on Earth capable of diving to the ‘full ocean depth’ of 36,000 feet. The only way to make my dream a reality was to build a new vehicle unlike any in current existence. Our success during seven prior expeditions building and operating our own deep-ocean vehicles, cameras, and lighting systems gave me confidence that such a vehicle could be built, and not just with the vast resources of government programs, but also with a small entrepreneurial team. It took more than seven years to design and build the vehicle, and it is still a work in progress. Every dive teaches us more, and we are continuing to improve the sub and its systems daily, as we move through our sea trials. — James Cameron

More than 50 years ago, two men climbed into a massive, blimp-like submersible, descended about 35,800 feet (10,912 meters) to the deepest point in the ocean, and became the first people to observe the dark underworld of one of Earth’s most extreme environments. No one had been back since, until March 26, 2012, when James Cameron , a National Geographic explorer-in-residence, made a record-breaking solo dive to the Challenger Deep in the Mariana Trench in a custom-built submersible that he co-designed.

Although best known for directing films such as  Titanic  and  Avatar , Cameron is an avid explorer with 72 submersible dives to his credit—51 of which were in Russian  Mir  submersibles to depths of up to 16,000 feet (4,877 meters), including 33 to  Titanic .

For this expedition, Cameron squeezed into a pilot sphere  so small he could not extend his arms. He was the sole occupant in a complex, 24-foot-long (7.3-meter-long) craft made primarily of highly specialized glass foam. As he maneuvered on the ocean floor amid unexplored terrain and strange new animals, Cameron filmed footage for a feature-length documentary and collected samples for historic research. Why? To promote exploration and scientific discovery.

The dive was part of the  DEEPSEA CHALLENGE  expedition, a partnership with  National Geographic  that took Cameron, along with fellow pilot Ron Allum and a team of engineers, scientists, educators, and journalists, to the greatest depths of the ocean—places where sunlight doesn’t penetrate and pressure can be a thousand times what we experience on land. After years of preparation, the team went to the Mariana Trench, a 1,500-mile-long (2,400-kilometer-long) scar at the bottom of the western Pacific Ocean. There, about 200 miles (320 kilometers) from Guam, Cameron continued the work that  Don Walsh and Jacques Piccard , the first men to dive the trench in the bathyscaphe Trieste , started in  1960 . While the  Trieste  was not equipped to take pictures or get samples, Cameron and his  DEEPSEA CHALLENGER  submersible were armed with multiple cameras and a mechanical arm for scooping up rocks and animals. These samples could enable groundbreaking discoveries: Studying the forces that shape these trenches could help us to better understand the earthquakes that cause devastating tsunamis; studying the fauna that survives there could lead to breakthroughs in biotechnology and our understanding of how life began.

For Cameron, who explored the  Titanic  wreck during his production of the Academy Award-winning film, reaching the deepest point on Earth was a long-term goal. “Imagination feeds exploration,” he says. “You have to imagine the possible before you can go and do it.”

Photograph by Charlie Arneson DEEPSEA CHALLENGER preparing for a dive

© 2023  DEEPSEA CHALLENGE , National Geographic. All rights reserved.

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Ocean observation focus at major UK marine science gathering

Scientists from the National Oceanography Centre (NOC) joined a major gathering of marine scientists this week (2-6 September) to talk about cutting edge marine science from the UK and beyond.

The Challenger Society Conference, being hosted by the Scottish Association of Marine Science in Oban, Scotland, attended by around 300 scientists, making it one of the UK’s largest ocean science focused events.

Giving keynotes at the event were NOC’s Professor Dan Jones, who leads our Ocean BioGeosciences group, and Dr Katy Hill, lead scientist for ocean research infrastructure, in her role as lead scientist on the Natural Environment Research Council’s (NERC) Future Marine Research Infrastructure (FMRI) programme.

NOC’s Chief Scientific Officer Professor Penny Holliday, who is being presented the Challenger Medal by event organiser the Challenger Society during the conference, alsp gave the Challenger Medal Lecture. 

In addition, scientists from across NOC’s science teams have been giving presentations and presenting posters across a wide range of topics relating to our understanding, use and protection of the ocean.

Driving ocean observation

A key theme is ocean observation, says Professor Jones, whose Wednesday keynote talk focussed on how disturbance of the deep ocean can be a sustaining force, but also destructive.

While the UK plays a major role in impacting what happens in the deep ocean, we still need a better understanding of what happens when deep ocean environments are disturbed by activities like deep sea mining to help support policy and decision making.

“Disturbance is a driving force for change and the maintenance of the conditions needed to support the diverse life in the deep ocean,” he says. “But what happens when humans start to interact in that environment with activities like deep sea mining?

“As scientists, through ocean observation, we need to provide the evidence and understanding of these processes, how systems change naturally, what disturbance does to the system and how it recovers, to help support policy and decision making.

“In the UK, there has been a steep change in understanding in this area over the last 10 years, but we do not have all the answers yet, so I’m keen to motivate the community towards this effort.”

A more digital vision for ocean science

Dr Katy Hill, who also presented her keynote on Wednesday in her NERC FMRI role, focussed on future ocean observation requirements through an initial insight into the draft FMRI Science Requirements Framework, looking forward to “Marine Science in 2040”.

This is a document, due to be shared for review with the national and international science community later this year, that will shape recommendations for investment into the UK’s future marine research infrastructure, to be delivered in March 2025. Key initial themes, gaps and opportunities will be discussed at the conference.

Key themes, she says, include five “grand challenges”, centred on our changing climate, biodiversity and ocean health, resilience to natural hazards, marine pollution and the blue economy and opportunities for investment. Opportunities include how we could better use digital capability to help combine the tools we have and drive more integration and insight, from planning and sampling through to modelling and the interplay between those.

But also, how to use digital platforms to help enable more multidisciplinary science, integrating physics, chemistry and biology data to be able to visualise and explore it more easily and efficiently.

Dr Hill's talk was followed by an afternoon of townhall-style discussions, to provide initial feedback on the “grand challenge” drafts and their cross-cutting issues.

A changing North Atlantic Ocean

Professor Holliday’s Challenger Medal talk, titled Changing North Atlantic Ocean: science, fun and persistence, took up the ocean observation theme on Thursday.

Professor Holliday says that understanding the way the Atlantic Ocean changes over time is both compelling to scientists and also now recognised as being crucial for our future wellbeing.

“I will trace a selected history of the past 50 years of observing and understanding of physical changes in the North Atlantic, told through the personal lens of my own research,” she said ahead of the event. “Along the way I’ll be reflecting on the fun and the challenges that science has given me, and highlighting how the way that we do our work is just as important as the work itself.”

Challenger Fellowships

The event, being held at Oban’s Corran Halls, also saw the presentation of Challenger Fellowships to Dr Anna Katavouta and Dr Tiago Segabinazzi Dotto. This recognition is reserved for early career scientists to acknowledge their outstanding accomplishments or potential in a branch of marine science. The fellowship was created by the Challenger Society in 2000 and is awarded biennially to members of the Society.

The conference is organised by the Challenger Society, named after the famous Challenger expedition (1872 – 1876), a highly influential scientific expedition that laid the foundations for modern-day marine science.

For more information visit: https://challenger2024.co.uk/

Notes to editors

For press enquiries, please contact: [email protected]  

NOC is the UK’s leading institution for integrated coastal and deep ocean research. NOC undertakes and facilitates world-class agenda-setting scientific research and technology development to understand the global ocean by solving challenging multidisciplinary, large scale, long-term marine science problems to underpin international and UK public policy, business and societal outcomes. NOC is a company limited by guarantee set up under the law of England and Wales (11444362) and registered as a charity (1185265).

NOC operates the Royal Research Ships James Cook and Discovery and develops technology for coastal and deep ocean research. Working with its partners NOC provides long-term marine science capability including: sustained ocean observations, mapping and surveying; data management and scientific research and advice.

Among the resources that NOC provides on behalf of the UK are the British Oceanographic Data Centre (BODC), the Marine Autonomous and Robotic Systems (MARS) facility, the National Marine Equipment Pool (NMEP), the National Tide and Sea Level Facility (NTSLF), the Permanent Service for Mean Sea Level (PSMSL) and British Ocean Sediment Core Research Facility (BOSCORF).

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Esri Releases New Book on Dr. Dawn Wright’s Historic Challenger Deep Dive

by [email protected] | Sep 6, 2024

Mapping the Deep: Innovation, Exploration & the Dive of a Lifetime  Explores the Importance of Mapping the Ocean

REDLANDS, Calif.  —  Esri,  the global leader in location intelligence, today announced the publication of  Mapping the Deep: Innovation, Exploration & the Dive of a Lifetime .

The new book by oceanographer Dr. Dawn Wright details the historic 2022 trip that made her the first Black person to visit Challenger Deep in the Mariana Trench, the deepest and most unexplored place on earth—over 10,000 meters beneath the Pacific Ocean’s surface.

We currently know less about the ocean floor than about the surface of the moon. Just one-fourth of the seabed has been mapped in high resolution to date, and as an ocean scientist and explorer, Wright has made it her mission to change that.

With a foreword by marine geologist Kathryn Sullivan, the first American woman to walk in space,  Mapping the Deep  takes readers on an adventure that showcases the perseverance and innovation required for ocean exploration. With a focus on Wright’s historic dive, her personal journey, and the cutting-edge technology that made the expedition possible, the book highlights the crucial importance of mapping the ocean and its profound impact on the planet’s future. From the fascinating history of Challenger Deep and its explorers to the diverse marine life that resides within,  Mapping the Deep  is a blend of history, fascinating facts, and beautiful images.

As chief scientist of Esri, Dr. Dawn Wright aids in strengthening the scientific foundation for Esri software and services while also representing Esri to the scientific community. A specialist in marine geology, with record-setting submersible dives in  Alvin  (to the East Pacific Rise),  Pisces V , and  Limiting Factor  (to Challenger Deep), she has also authored and contributed to some of the most definitive literature on marine GIS.

Mapping the Deep  is available in paperback (ISBN: 9781589487888, US$26.99) and as an ebook (ISBN: 9781589487895, US$26.99). This book can be obtained from most online retailers worldwide. Interested retailers can contact Esri Press book distributor Ingram Publisher Services.

Esri, the global market leader in geographic information system (GIS) software, location intelligence, and mapping, helps customers unlock the full potential of data to improve operational and business results. Founded in 1969 in Redlands, California, USA, Esri software is deployed in hundreds of thousands of organizations globally, including Fortune 500 companies, government agencies, nonprofit institutions, and universities. Esri has regional offices, international distributors, and partners providing local support in over 100 countries on six continents. With its pioneering commitment to geospatial technology and analytics, Esri engineers the most innovative solutions that leverage a geographic approach to solving some of the world’s most complex problems by placing them in the crucial context of location. Visit us at  esri.com .

Copyright © 2024 Esri. All rights reserved. Esri, the Esri Globe and Frame logos, The Science of Where, esri.com, and @esri.com are trademarks, service marks, or registered marks of Esri in the United States, the European Community, or certain other jurisdictions. Other companies and products or services mentioned herein may be trademarks, service marks, or registered marks of their respective mark owners.

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