Deep Sea Exploration

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[CaaC (John)+]

@nudge, you will love this, a long read though 

 

Mariana Trench: Deepest-ever sub dive finds a plastic bag

By Rebecca MorelleScience Correspondent, BBC News

An American explorer has found plastic waste on the seafloor while breaking the record for the deepest ever dive.

Victor Vescovo descended nearly 11km (seven miles) to the deepest place in the ocean - the Pacific Ocean's Mariana Trench.

He spent four hours exploring the bottom of the trench in his submersible, built to withstand the immense pressure of the deep.

He found sea creatures, but also found a plastic bag and sweet wrappers.

It is the third time humans have reached the ocean's extreme depths.

https://www.bbc.co.uk/news/science-environment-48230157

[CaaC (John)+]

Mysterious shark ‘older than the dinosaurs’ caught on film

Rob Waugh

The shark was captured on film (Ocean X)

A shark which has been on our planet for nearly 200 million years, and which has eluded researchers has finally been caught on film - and tagged.

It’s the first time the bluntnose sixgill has been satellite-tagged in this way, the researchers say, with the mysterious creatures usually staying 8,200 feet down.

The team from Ocean X and Florida University tagged the creature from a submersible vehicle.

It’s the first time this has ever been achieved, as the creatures have previously been ‘surface-tagged’ (ie taken to the surface), which researchers have worried could affect the data.

Gallery: Amazing facts about sharks (Best Life)

The researchers wrote, ‘Because bluntnose sixgills are a deep-sea species, it’s hard on them physiologically to be tagged in this way.

‘In their typical life cycle, they won’t experience daylight, and very rarely will they feel the low pressure, warmer temperatures of surface waters.

© Provided by Oath Inc. The shark was captured on film (Ocean X)

Typically, the data obtained after surface tagging of a sixgill is believed to be skewed, as the shark does not return to its natural behaviours for some time after the tagging.’

In a blog post, the researchers write, ‘This is historic for a variety of reasons. Now that we’ve proven this method can work for the sixgill, we can unlock the world of leviathan deep-sea dwellers and gain important insights into their movement and behaviour.’

https://www.msn.com/en-gb/news/techandscience/mysterious-shark-older-than-the-dinosaurs-caught-on-film/ar-AAE27ue?ocid=chromentp

[CaaC (John)+]

Shiver...imagine looking around and seeing that big eye looking at you...yipes  

 

'Monster' Shark Bigger Than a Submarine Filmed by Scientists As It Tries to Eat Their Gun

Aristos Georgiou

© OceanX Bluntnose sixgill biting off bait during an OceanX tagging mission.

A team of researchers has captured incredible footage of a close encounter with an ancient species of shark known as the bluntnose sixgill.

The team, led by Dean Grubbs, from Florida State University, were conducting dives in a submersible called "Nadir" as part of an expedition organized by OceanX to tag one of the sharks in their deep-sea environment.

During one of the dives, the team were fortunate to come up close and personal with a huge female bluntnose—=one of the largest sharks in the world—which one of the researchers in the video can be heard describing as "definitely bigger than the sub is long."

The sub crew were left in a state of awe by the encounter: "My goodness that is amazing," one of the team comments, while another can be heard saying, "This is a monster. She is huge." At one point the shark even tries to nibble on the speargun attached to Nadir.

The bluntnose (Hexanchus griseus) is part of an old lineage of sharks that can be traced back 180 million years in the fossil record. In fact, it represents perhaps the oldest living lineage of sharks in the world, the researchers say. They are highly distinctive due to the fact that they have six large conspicuous gill slits, hence the name. Most sharks only have five.

"They have a single dorsal fin that is placed far back on the midline near the tail," Gavin Naylor, one of the scientists on the expedition from the Florida Program for Shark Research at the Florida Museum of Natural History, told Newsweek. "They are reported to grow to over 5 meters [16 feet] long and weigh more than a ton. They are live-bearing. Females can have over 80 pups in a litter. They are likely primarily carrion feeders, but may also take live prey when the opportunity arises. Females are larger than males."

Bluntnose sixgills are distributed across tropical and temperate waters around the world usually living at depths of between 650 and 3,300 feet, although they have been spotted up to 5,000 feet below the surface. However, researchers know very little about this mysterious species. Tagging them could enable scientists to learn more about their biology and behaviour, and protect them from threats.

"Approximately half of all living species of sharks on the planet live their entire lives in the deep sea," Grubbs told Newsweek. "Yet we know virtually nothing about their biology and ecology. Contrast this with the volumes of scientific information on species like white sharks and tiger sharks. Yet as commercial fisheries globally move deeper, deep-sea sharks are being increasingly caught, particularly as bycatch."

"It is often assumed that these deep-sea sharks would die if released," he said. "We began this project in 2005 to begin investigating whether deep-sea sharks caught and brought to the surface survive if released. Since this time we have tagged more than 20 bluntnose sixgill sharks with archiving satellite tags and another 50 with simple identification tags. But all of these were tagged by bringing the sharks to the surface and tagging them alongside the boat or even bringing them onto the deck of the ship."

This tagging revealed to the researchers that nearly all bluntnose six gills survive being caught and brought to the surface. Furthermore, the data showed, intriguingly, that these sharks vertically migrate every day and night.

"At dusk they come up the slope sometimes in the water column to shallower depths where the water temperature is about 62 degrees Fahrenheit, remaining there overnight, and then at dawn, they return to deeper depths where temperatures are 41 degrees Fahrenheit," Grubbs said. "In Exuma Sound [the Bahamas,] this corresponds to coming up to 400-500 meters [1,312-1,640 feet] deep at night and remaining at 900-1200 meters [2,952-3,937 feet] during the day. This is a beautifully consistent vertical pattern the sharks undergo every day."

"However, one of the things we noticed is that across all of these sharks there was an initial period of about two days after tagging where the sharks did not show this pattern and seemed to behave a bit more erratically, and then they settled into that distinct vertical migration every day after that," he said. "We interpreted that erratic phase as a possible recovery period due to short term physiological stress associated with being captured and brought to the surface."

This stress could be enough to temporarily alter this behaviour, even though the sharks seemed to tolerate being brought to the surface. This finding is what led the team to try and tag a bluntnose in the deep-sea instead.

"So how do we test the theory that this initial difference in behaviour represents recovery from capture?" Grubbs said. "We go directly to the sharks in their natural habitat and tag them at depth. This drove our efforts to attempt to tag these sharks at depth. We made three expeditions and many dives spending many hours sitting on the bottom trying to get the sharks to come in and then trying to tag them. We came very close numerous times but never quite had the right shot, or in one case, the shark knocked the spear off the gun and dislodged the tag! But finally, on the last dive on this last expedition [in Exuma Sound,] my colleague Gavin Naylor successfully tagged a sixgill from the sub!"

This tag will remain on the shark for 3 months, before detaching, floating to the surface and uploading the data it has collected via satellite link to a processing centre where it can be analyzed.

"If our theory is correct, we expect to see the same vertical migration behaviour as the other sharks demonstrated but without the initial two days of erratic behaviour," Grubbs said. "Unfortunately, we have to wait impatiently to hear from that tag!"

Currently, the worldwide population of bluntnose sixgills is unknown but they are listed as "Near Threatened" on the International Union for Conservation of Nature's Red List. Nevertheless, the researchers suggest that they are perhaps more common than previously appreciated.

"Finding a six-gill shark at depth turned out to be much less of a challenge than many had imagined," Gaylor said. "They seem reasonably common. Finding a marine biologist willing to go down in a submarine to try to tag a six-gill at depth was the easiest part!"

https://www.msn.com/en-gb/news/offbeat/monster-shark-bigger-than-a-submarine-filmed-by-scientists-as-it-tries-to-eat-their-gun/ar-AAFfShR

 

[CaaC (John)+]

Victor Vescovo: Adventurer reaches deepest ocean locations

VIDEO

US adventurer Victor Vescovo has become the first person to visit the deepest points in every ocean.

His fifth and final dive in a prototype submersible was made to the bottom of the Arctic's Molloy Trench, some 5.5km (3.4 miles) below the sea surface.

This followed dives during the past 10 months to the floor of the Pacific, Indian, Southern and Atlantic oceans.

The millionaire financier's team also visited the wreck of the Titanic.

All Mr Vescovo's dives were made using the 12-tonne Deep Sea Vehicle (DSV) Limiting Factor, launched and recovered from a dedicated support ship, the DSSV Pressure Drop, ironically a one-time navy submarine hunter.

• Deepest-ever sub dive finds plastic waste
• Robot duo wins ocean-mapping XPRIZE

The last leg of the "Five Deeps Expedition" was concluded on 24 August when the explorer reached a spot known as the Molloy Hole, which is about 275km (170 miles) west of Norway's Svalbard archipelago.

The recorded depth on the solo dive was 5,550m, plus or minus 14m. It is the first time any human has been to this location.

FULL REPORT

 

Edited September 11, 2019 by CaaC (John)
Insert Video Link

[CaaC (John)+]

World's deepest octopus captured on camera

The deepest-ever sighting of an octopus has been made by cameras on the Indian Ocean floor.

The animal was spotted 7,000m down in the Java Trench - almost 2km deeper than the previous reliable recording.

Researchers, who report the discovery in the journal Marine Biology, say it's a species of "Dumbo" octopus.

The name is a nod to the prominent ear-like fins just above these animals' eyes that make them look like the 1940s Disney cartoon character.

• US adventurer reaches deepest points in all oceans
• Deepest-ever sub dive finds plastic waste
• Robot duo wins ocean-mapping XPRIZE

The scientist behind the identification is Dr Alan Jamieson.

He's pioneered the exploration of the deep using what are called "landers".

These are instrumented frames dropped overboard from research ships.

They settle on the seabed and record what passes by.

FULL REPORT

Edited May 29, 2020 by CaaC (John)

[nudge+]

Alexander Semenov, the head of the scientific diving team at the White Sea biological station of Lomonosov’s Moscow State University, has been sharing incredibly stunning underwater photos of deep ocean creatures.

Mind blowing...

[Stan]

Evolution is a funny old thing.

Such weird and wonderful creatures down there. The photography of it all is impressive too.

[Bluewolf]

6 minutes ago, nudge said:

Alexander Semenov, the head of the scientific diving team at the White Sea biological station of Lomonosov’s Moscow State University, has been sharing incredibly stunning underwater photos of deep ocean creatures.

Mind blowing...

Incredible images... 

[Stan]

Probably not that deep but this is pretty cool... 

 

[CaaC (John)+]

World’s longest animal discovered in Australian waters

The 46-metre-long siphonophore was found lurking 625 metres beneath the waves off the Western Australian coastline.

By Jason Goodyer
09th June 2020 

A deep-sea expedition led by the Schmidt Ocean Institute has discovered 30 potentially new species of marine creatures, including a siphonophore that’s thought to be the longest animal ever observed.

It has been estimated to be 46 metres long, nearly six times the length of a Routemaster double-decker bus.

Though they appear to be a single animal, each siphonophore is in fact a colony of organisms that clone themselves thousands of times and join together to form long chains. Like jellyfish, they have stingers that ensnare, paralyse and kill prey.

The discoveries were made using ROV SuBastian, a remotely operated robotic vehicle that’s capable of diving to depths of 4.5 kilometres.

The expedition in pictures

ROV SuBastian is lifted back on deck after a day of diving © Greg Rouse Scripps Oceanography/Nerida Wilson/FK200308 team

The 46m-long siphonopore is thought to be the longest animal ever discovered

The expedition found several other species that may be new to science 

Chief scientist Dr Nerida Wilson takes samples of a hymenaster, a type of deep-sea starfish, for DNA profiling

This zoarcid fish was collected from a trap mounted on the lander 

This rare deep-sea hydroid, a close relative of corals and anemones, was found 2.5km deep in Cape Range Canyon

This squat lobster species are distributed all over the globe, but this is the first time one has been found in Western Australia

https://www.sciencefocus.com/news/worlds-longest-animal-discovered-in-australian-waters/

Edited June 13, 2020 by CaaC (John)

[nudge+]

46 meters long  

[CaaC (John)+]

17 minutes ago, nudge said:

46 meters long  

Imagine swimming underwater and seeing that creeping towards you, I would shite a brick and get out of the water quick smart 

[CaaC (John)+]

Siphonopore

[CaaC (John)+]

I will post this in here, I was torn between the Space: The Final Frontier thread or in here, Inga's thread, Kathy Sullivan has done both, went into the wild blue yonder of Space and to the bottom of the ocean in the Challenger Deep Dive, what a lady 

Kathy Sullivan: The woman who's made history in sea and space

Making headlines is never something that has motivated Kathy Sullivan.

Already in the history books as the first US woman to complete a spacewalk in 1984, the 68-year-old found herself in the news again this week after becoming the first woman to travel almost seven miles (11km) to reach the lowest known point in the ocean.

The two missions, total opposites in the minds of some, represent two extremes of a lifelong passion for Dr Sullivan: to understand the world around her as much as possible.

"I was always a pretty adventurous and curious child with interests wider and more varied than the stereotype of a little girl," Sullivan told the BBC in a phone interview from the Pacific Ocean.

She was born in New Jersey in 1951 and spent her childhood in California. Her father was an aerospace engineer who, along with her mother, would always encourage their two children to think freely and join in with discussions.

"They really fed our curiosity on anything we were curious about or interested in," she says. "They were our best allies to explore that interest further and see where it might take us: it might die out in a couple of days, it might be something that became our best hobby or it might turn into the central focus of our career."

By the time they were five or six, it was already clear her brother wanted to grow up to fly aeroplanes. Sullivan, meanwhile, became fascinated by maps and learning more about the interesting places on them.

"Both of our careers have basically been remarkably wonderful fulfilments of those early dreams," she reflects.

FULL REPORT

 

 

Edited June 14, 2020 by CaaC (John)

[CaaC (John)+]

Mariana Trench: Don Walsh's son repeats historic ocean dive

It used to be said that more people had walked on the surface of the Moon than had dived to the deepest part of Earth's oceans. Not anymore.

Kelly Walsh, the son of the great ocean explorer Don Walsh, has just descended to the bottom of the Mariana Trench, almost 11km down in the Pacific.

He made the dive 60 years after his father created history in doing so.

It means Kelly is the 12th person to visit the trench floor - the same as the number of Apollo moonwalkers.

The 12-hour dive on Saturday saw him reach a depth of approximately 10,925m.

Kelly described it as "a hugely emotional journey" after returning to the surface.

• US adventurer reaches deepest points in all oceans
• Deepest-ever sub dive finds plastic waste
• The woman making history in sea and space
• World's deepest octopus captured on camera

FULL REPORT

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The 12 who've dived to the floor of the Mariana Trench

• Jacques Piccard (Switzerland) 1960 (bathyscaphe Trieste)
• Don Walsh (US) 1960 (bathyscaphe Trieste)
• James Cameron (Canada) 2012 (DeepSea Challenger HOV)
• Victor Vescovo (US) 2019 (DSV Limiting Factor)
• Patrick Lahey (Canada) 2019 (DSV Limiting Factor)
• Jonathan Struwe (Germany) 2019 (DSV Limiting Factor)
• John Ramsay (UK) 2019 (DSV Limiting Factor)
• Dr Alan Jamieson (UK) 2019 (Sirena Deep, 10.7 km depth; DSV Limiting Factor)
• Dr Kathryn Sullivan (US) 7 June 2020 (DSV Limiting Factor)
• Vanessa O'Brien (US/UK) 11 June 2020 (DSV Limiting Factor)
• John Rost (US) 14 June 2020 (DSV Limiting Factor)
• Kelly Walsh (US) 20 June 2020 (DSV Limiting Factor)

Source: Dr Jon Copley @expeditionlog

[CaaC (John)+]

Toxic mercury pollution found in the ocean’s deepest point

Two independent teams of scientists have found methylmercury in fish and crustaceans captured in the 11,000-metre-deep Mariana Trench.

Human-derived mercury is a serious threat to the marine world, and now it seems to have infiltrated into the deepest, remotest parts of the ocean.

While mercury is a naturally occurring element that can be introduced to the environment through volcanic eruptions and forest fires, human-derived mercury from industrial activity, incineration, mining and energy generation boosts the amount of airborne mercury, which eventually finds its way into the rivers and oceans.

It then works its way through the food chain, accumulating in marine animals, with larger predators like swordfish and sharks containing particularly high quantities

Mercury is toxic to humans and other animals and can lead to birth defects and neurological problems.

The submersible Deep Sea Warrior, used by Ruoyu Sun’s team © Sun Qing/Getty Images

Now, two independent teams of scientists have found a toxic form of mercury, methylmercury, present in fish and crustaceans captured in some of the deepest ocean trenches, including the 11,000-metre-deep Mariana Trench.

“This is a surprise,” said researcher Dr Ruoyu Sun, from Tianjin University, China. “Previous research had concluded that methylmercury was mostly produced in the top few hundred metres of the ocean.

“This would have limited mercury bioaccumulation by ensuring that fish which forage deeper than this would have had limited opportunity to ingest the methylmercury. With this work, we now believe that isn’t true.”

Hadal snailfish Notoliparis kermadecensis at 7,000m in the Kermadec Trench off New Zealand as sampled by Joel Blum’s team © Alan Jamieson

The researchers concluded that the particular form of mercury found within the creatures was not produced naturally in the deep-sea environment, and much of it is likely to have come from human activity.

“We know that this mercury is deposited from the atmosphere to the surface ocean and is then transported to the deep ocean in the sinking carcasses of fish and marine mammals, as well as in small particles,” said Dr Joel Blum, from the University of Michigan.

This research has demonstrated the far-reaching impact that human activity can have on even the remotest environments, and will lead to greater understanding about how mercury affects the marine world.

• Are all the world’s oceans at the same level?
• How long would a pebble take to reach the bottom of the Mariana Trench?

https://www.sciencefocus.com/news/toxic-mercury-pollution-found-in-the-oceans-deepest-point/

[nudge+]

Fabien Cousteau is following in the footsteps of his grandfather and intends to build Proteus - an underwater version of the International Space Station, which would be the world's largest underwater research station and habitat.

https://www.ecowatch.com/ocean-research-proteus-underwater-station-2646792937.html

First design renders:

 

 

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[CaaC (John)+]

Robots go their own way deep in the ocean

"It's very common," says Jess Hanham casually, when asked how often he finds suspected unexploded bombs.

Mr Hanham is a co-founder of Spectrum Offshore, a marine survey firm that does a lot of work in the Thames Estuary.

His firm undertakes all sorts of marine surveying, but working on sites for new offshore wind farms has become a big business for him.

Work in the Thames Estuary, and other areas that were the targets of bombing in World War 2, are likely to involve picking up signals of unexploded munitions.

"You can find a significant amount of contacts that need further investigation and for a wind farm that will be established in the initial pre-engineering survey," he says

With that information project managers can decide whether to place turbines and other equipment a safe distance from the suspected bombs or have them blown up by a specialist firm.

At the moment marine surveying is done by teams who go out on boats, collect the data and bring it back for analysis.

Sometimes that will involve a relatively small vessel with two crew members, a surveyor and his kit. But bigger inspection projects further out to sea can involve much larger boats, with dozens of crew members, costing in the region of £100,000 per day.

The sensor equipment varies according to the job. Sometimes it might be a sonar array towed behind the boat, for other jobs it might be an underwater unmanned vehicle, which can be controlled by surveyors on the surface.

Bad weather can disrupt the work and make life uncomfortable. "I've been at sea in force nine and force 10 gales and they're not nice places to work," says Brian Allen, chief executive of Rovco.

FULL REPORT

[Mpache]

Not sure if this is related to the thread, but this is awesome.

 

[CaaC (John)+]

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How did mercury get down there?

Two new views on a very deep problem.

Mercury has been found in the deepest part of the Earth’s oceans, the 11,000-metre-deep Mariana Trench in the northwest Pacific. But how did it get there?

In recent months, two groups of scientists have been surprised to find it but put forward two different explanations.

In July, a team led by Ruoyu Sun from China’s Tianjin University proposed, in a paper in the journal Nature Communications, that it essentially hitches a ride on microscopic particles of sinking organic matter – including faecal material and dead plankton – that constantly rain down from the upper oceans.

However, in a paper just published in PNAS, a team led by Joel Blum from the University of Michigan, US, suggests that a more likely explanation is that sinking carrion from fish that feed in the upper ocean deliver most of the mercury to the trenches.

And most of that mercury began its long journey, Blum and colleagues say, as atmospheric emissions from coal-fired power plants, mining operations, cement factories, incinerators and other human activities.

They draw their conclusions after analysing the isotopic composition of mercury in fish and crustaceans collected at the bottom of the Mariana Trench and the Kermadec Trench in the southwest Pacific.  

“It was widely thought that anthropogenic mercury was mainly restricted to the upper 1000 metres of the oceans, but we found that while some of the mercury in these deep-sea trenches has a natural origin, it is likely that most of it comes from human activity,” says Blum.

Why does it matter whether the mercury was carried by sinking fish carcasses or the steady rain of tiny bits of detritus? Because Blum says, scientists and policymakers want to know how changing global mercury emissions will affect the levels found in seafood.

To determine how seafood is likely to be impacted, researchers rely on global models, and refining those models requires the clearest possible understanding of how mercury cycles within the oceans and between the oceans and the atmosphere.

“Yes, we eat fish caught in shallower waters, not from deep-sea trenches,” Blum says. “However, we need to understand the cycling of mercury through the entire ocean to be able to model future changes in the near-surface ocean.”

Anthropogenic mercury enters the oceans via rainfall, dry deposition of windblown dust, and runoff from rivers and estuaries. And it is not alone in the trenches.

“Deep-sea trenches have been viewed as pristine ecosystems unsullied by human activities, but recent studies have found traces of anthropogenic lead, carbon-14 from nuclear weapons testing, and persistent organic pollutants such as PCBs in organisms living in even the deepest part of the ocean…,” says co-author Jeffrey Drazen, an oceanographer with the University of Hawaii.

Both teams presented their findings to the online Goldschmidt geochemistry conference in June, but at that stage, neither paper had been peer-reviewed.

https://cosmosmagazine.com/earth/earth-sciences/how-did-mercury-get-down-there/

 

 

[CaaC (John)+]

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Mapping the undersea landscape of the reef

Four researchers on a boat, despite the pandemic.

Overview of Sykes Reef on the Great Barrier Reef from RV Falkor multibeam data. Credit: SOI

About 160 kilometres off the Queensland coast, the RV Falkor is exploring the deep blue waters of the southern Great Barrier Reef in search of drowned worlds.

The research vessel – operated by the Schmidt Ocean Institute – is nearing the end of a month-long expedition to map undersea features that formed during the last Ice Age, to help us better understand today’s rapidly changing reef environment.

“We’re on the outside the Great Barrier Reef, off the continental shelf, in an area called the Capricorn Channel,” explains Mardi McNeil, a marine geoscientist from the Queensland University of Technology (QUT), speaking to me from the “library” on the Falkor.

McNeil is leading the expedition’s four-person science team, cut down to the bare minimum due to COVID restrictions.

With her are QUT PhD student Haydn Trounce, recent geology graduate Ella Sinclair, and University of Queensland Honours student Ben Houseman. For them, this expedition is constantly exciting. “Most days, you can do a lap of the ship and as far as the eye can see, it’s just the horizon of the water,” says Trounce. “It’s a really cool thing to see.”

This is McNeil’s fourth voyage aboard Falkor, one of the few research vessels to conduct scientific expeditions through the pandemic. It has been in Australian waters since last December and its schedule has been constantly re-arranged. With many voyages cancelled, McNeil’s group has snagged three in a row.

“It’s incredible; this is a decade’s worth of ship time and research,” she says. But it’s been hectic. The current voyage was planned and executed in two and a half weeks. “Normally, you plan a research cruise in about 18 months to two years.”

By the time McNeil returns home for Christmas, she will have spent 110 days at sea since August: nearly four months out of five.

This expedition is the final leg of a three-part adventure to map the undersea landscape along the length of the GBR, from the tip in Torres Strait to the southern edge, several hundred kilometres north of Brisbane.

“Those previous cruises had their own objectives and questions, but they are all interrelated,” McNeil says. “In a sense, this is the final piece of the puzzle.”

The main scientific goal is to explore, discover and map ancient features of the reef from up to 20,000 years ago. At that time, the Earth was in the grip of the Last Glacial Maximum. Much of its water was locked up in glaciers and ice sheets, so coastlines looked very different.

FULL REPORT

 

 

[Azeem]

What is the vastness of the ocean without a giant monster lurking in the dark. It's like sleep without dreams ~

[CaaC (John)+]

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Companies back moratorium on deep-sea mining

A long-running dispute over plans to start mining the ocean floor has suddenly flared up.

For years it was only environmental groups that objected to the idea of digging up metals from the deep sea.

But now BMW, Volvo, Google and Samsung are lending their weight to calls for a moratorium on the proposals.

The move has been criticised by companies behind the deep-sea mining plans, who say the practice is more sustainable in the ocean than on land.

The concept, first envisaged in the 1960s, is to extract billions of potato-sized rocks called nodules from the abyssal plains of the oceans several miles deep.

FULL REPORT