SINGAPORE – Just as aspiring astronauts yearn to go to outer space to walk the craters of the moon, film-maker James Cameron had dreamt, since he was a boy, of traversing territory that even fewer have set foot on – the depths of the ocean floor. 

In 2012, piloting a submersible that he helped to design and engineer, Mr Cameron ventured into the frigid, oceanic valleys of the Mariana Trench, reaching its deepest point – Challenger Deep – at more than 11km from the water’s surface, where sunlight does not penetrate, and the water pressure is bone-crushing. 

On a mission previously thought to be unachievable, Mr Cameron spent some three hours in the muddy trenches of the Challenger Deep, collecting rock and sediment samples, and taking footage of the mysterious fauna that occupied it.

While the single dive alone yielded some 68 new species, attempts to grab rock and sediment samples were hampered by the damage wrought by the immense pressure on the submersible’s hydraulic arms.

By the time Mr Cameron reached the sea floor, several pieces of equipment had begun to fail – his batteries running low, his compass glitching, and the submersible’s sonar, which used soundwaves to navigate underwater, dying completely, he said in an article for the National Geographic in 2013.

After some three hours, the vessel had also lost so many of its propellers that it became an increasingly uphill task to retain control of it, forcing Mr Cameron to return to the surface. 

While the film-maker’s trip might have interested mainly aficionados, millions around the world were gripped by the implosion of the Titan tourist submersible in June 2023. The vessel was bound for the wreckage of the Titanic, lying 4km deep, when it was crushed by the water pressure, killing all five people on board, including operator OceanGate’s chief executive Stockton Rush.

Engineering professor Roderick Smith of Imperial College London told AFP the incident was likely due to a “failure of the pressure hull”, which helps to maintain normal pressure within the vessel as it submerges deeper underwater.

Some suggested the material used to construct the pressure hull, a more buoyant carbon fibre instead of the traditional titanium, was unable to withstand the immense pressure of nearly 6,000 psi (pounds per sq inch). But it is difficult to fully pinpoint the cause of the submersible’s implosion.

The frontiers of man’s imagination

While the construction of deep-sea submersibles to be able to withstand the harsh conditions below is a feat of engineering, humankind has been willing to take these risks to explore earth’s last frontier, some for tourism, and others to better understand the very origins of life. 

For instance, expeditions to hydrothermal vents – the sulphur-infused, volcanic hot springs of the ocean – have provided clues to scientists on how life may have begun on the planet.

A 2019 study by Nasa simulating the conditions of the primordial ocean in laboratory settings suggested that the conditions around the hydrothermal vents could have helped to kick-start the chemical reactions that created the key amino acids and organic compounds essential for life.

The vents result from fissures in the sea floor, where hot magma wells up to heat seawater to a staggering 350 deg C.

Surrounded by hot, belching chimneys of black smoke, in a place once thought by scientists to be wholly inimical to life, giant tube worms thrive. 

These worms can grow up to 2m in length, and they do not eat. Instead, they rely on bacteria inside their guts to convert chemicals like sulphur into energy.

In a place completely devoid of sunlight and oxygen, these creatures have thrived, proving the extreme, almost implausible, adaptability of life.

But it’s not just scientists who have an interest in the ocean floor.

Besides providing sustenance for marine life, the hot fluids expelled from the vents are also rich in dissolved metals like copper, gold, silver and zinc, which have become extremely valuable in the green energy transition. 

To be able to make deep cuts to greenhouse gas emissions, countries are phasing out internal combustion engine cars in favour of electric vehicles, while also ramping up the use of renewable energy. All this has created an insatiable appetite for lithium, nickel, and important metals like copper, silver and zinc needed in the production of batteries and solar panels.

Increasingly, countries are looking to the ocean bed for these minerals.

Technological advancements have made mining an easier feat, with remotely operated mining vehicles plying the seabed, scraping up minerals and surface sediments that are then piped up to the main collection vessel for processing. Once the minerals have been retrieved, waste and remaining sediments are pumped back and returned to the ocean. 

Battle for ownership of ocean floor minerals

Mining companies in quest of these metals have fomented a battle over the deep sea, where rules are murky, and the wider potential impact to the environment undetermined. 

One particular area of interest is the Clarion-Clipperton Zone (CCZ), a patch spanning 4.5 million sq km in the Pacific Ocean between Mexico and Hawaii. It holds an abundant 21 billion tonnes of polymetallic nodules and rare earth minerals – supposedly more than all known land deposits combined.

These potato-sized polymetallic nodules lie on vast tracts of the sea floor, having formed in clumps through natural processes occurring over thousands of years.

Companies keen for a slice of the seabed can apply for exploratory mining permits with the United Nations’ International Seabed Authority (ISA), which is responsible for sea floor mining in areas beyond countries’ national jurisdictions.  

Each permit will give a company the remit of some 75,000 sq km for exploration of the seabed.

At least 30 contracts for exploratory mining have already been given out, the majority of them in the CCZ.

Singapore’s Ocean Mineral – a subsidiary of Keppel Offshore & Marine – has also been given the go-ahead to conduct seabed surveys within an approved area of 58,000 sq km, about 80 times the size of Singapore, to mine the nodules in an environmentally friendly way.

Two expedition trips have been conducted so far, in 2015 and 2020, for environmental baseline surveys within the designated area of the CCZ.

In 2021, the Pacific island nation of Nauru notified the ISA of its plans to begin mining in international waters, kicking off a process which would require the authority to adopt mining regulations by July 2023, or allow countries to start mining operations regardless of the rules in place by then. 

The small island nation, which is sinking as a result of sea level rise, has turned to deep sea mining as an economic lifeline, and has repeatedly called on countries to pursue electrification as a way of greening their economies.

But countries located near the CCZ, like Fiji, Palau and Samoa, have strongly opposed such mining for fear that it could compromise marine life in those zones, of which so much is still unknown.  

The toxic sedimentation plumes from mining, clouds of suspended particles that occur when sea floor sediment is disturbed, could disturb marine creatures in the vicinity, for instance, and destroy key habitats in the process.

It is also unclear whether the dislodging of these deep sea sediments would inevitably release stores of carbon dioxide trapped in them and worsen the impacts of climate change. 

Some 800 scientists have signed a statement calling for a moratorium on deep sea mining until more is understood of its potential ecological impact.

In a study conducted in May 2023, scientists found more than 5,000 species that were new to science in the CCZ, including worms, members of the spider family, and spiny invertebrates like sea urchins and sponges.

Amid opposition from some countries like France, Chile and Canada, the ISA decided in July 2023 to postpone its authorisation for deep sea mining for two years until 2025 at the earliest, to allow for more time to closely study its potential environmental implications and other teething issues. 

As negotiations on the issue continue into 2024, strong proponents of deep sea mining are already lobbying to ensure that the authorisation timeline remains on track. 

For instance, Canadian deep sea mining firm The Metals Company is looking to start mining as soon as possible, in 2025 at the earliest. 

As the fate of the oceans hangs in the balance, there is a growing momentum among countries to call for caution, with some 25 of them calling for a moratorium on mining, or at least a “precautionary pause” on these activities.