Deep sea mining: A necessary industry or too much risk?

Travel far enough away from the coast and things quickly develop into the open ocean, what scientists call the ‘pelagic zone’. If we take the same size patch of ocean, then these open water regions are pretty unproductive - relatively speaking – when compared to other zones like coral reefs. But because the pelagic zone is simply so vast, collectively it actually has more primary production than any other marine habitat.

But it is what lies beneath these open waters that is of recent intense interest. 

Diving 4,000 metres below the surface of the open ocean and we reach the abyssal zone. At these depths the ocean is pitch black and the water hovers just above freezing. Stretching out for thousands of kilometres in all directions are vast, muddy plains occasionally interrupted by climbing underwater mountains or huge cracks in the crust plunging ever deeper into the planet.

While these large expanses of the deep-sea abyssal floor appear uninhabited, they are actually teeming with life. A recent study found there could be up to 8,000 species living down there in the cold dark. But despite sampling going back to the 1960s, scientists have only identified around 10% of these animals – the rest are completely unknown to science. There’s a whole wealth of life we’re yet to discover here.

Dr Maria Belen Arias Mella is a Natural History Museum researcher who is studying this deep-sea life. She is involved with looking at the genetics of the animals found on the seafloor, and recently went on a scientific expedition to collect new samples of these creatures from the Pacific Ocean.

‘In terms of the diversity, as far as we know the abyssal plains have really high diversity but at low abundance,’ says Belen. ‘Almost all the animals that we pick up are different from one another.’ 

‘Life probably started in these sorts of regions, but to be honest we don’t know because finding so much life down there was unexpected. It is an oligotrophic [low nutrient] environment, so resources are very scarce. They don’t have food or light, so how is it so highly diverse?’

What are polymetallic nodules?

As the name suggests polymetallic nodules are made up of several different types of metals. It just so happens that the metals they contain are the same ones we need to transition to renewable energy and other green technologies: manganese, cobalt, nickel and copper.

In total, it is thought that there are up to 21 billion tons of these nodules littering the bottom of the CCZ, which could potentially provide enough raw metals needed to meet our demand for things like batteries and solar panels for over a century. And as technology has developed over the past few decades, this has made the prospect of mining the deep sea for these nodules not only more desirable but also more feasible.

These nodules form exceedingly slowly through chemical processes at the seafloor which causes the metals to precipitate out of the water around tiny objects such as shell fragments and sharks teeth. It is thought that it takes roughly a million years for these nodules to grow just tens of millimetres in size. Since the largest nodules found reach around 20 centimetres across, it suggests that these environments have been unchanged at the bottom of the oceans for tens of millions of years.

It is this extreme stability that also means these environments are extraordinarily diverse and the animals found there unimaginably long-lived.

The life at these depths is unlike anything anywhere else on this planet. There are ethereal sponges that look like little shining orbs on the end of a stick that sway gently in the current, as chubby sea cucumbers with a deep purple hue amble along the seafloor. Rising from the nodules themselves are beautifully elegant sea lilies, whilst actually within the nodules rainbow-tinged worms have set up home. 

Everything from the smallest bacteria and worms, to anemones, molluscs, bryozoans, corals, crustaceans and fish can be found burrowing through the sediment, swimming through the water, and living on the nodules.

‘The spirit of UNCLOS is that everyone has a stake in the seafloor’, explains Muriel. ‘It is owned by no one [person or entity], so that any benefits deriving from the seafloor and the subsoil thereof will be evenly distributed.’

‘Very strictly it is seabed, but exactly where that starts is debatable, in terms of the water column. For example, is it one metre above the seafloor or ten metres?’

The UNCLOS was a monumental agreement for humanity to reach, as it gave every single nation a duty to protect and respect the seafloor in the interest of every other person alive today and in the future. It meant that no private or public organisation could exploit any potential resources on their own, and that all nations must actively share with each other any benefits acquired. 

What is the International Seabed Authority?

The Common Heritage of Humankind meant that there needed to be an independent organisation to administer and regulate the seafloor, and so in 1994 the UN created the International Seabed Authority (ISA), an intergovernmental body made up of 167 member states and the European Union. As interest in mining the deep seafloor grew, it was the ISA’s job to assess and grant licenses to mining concessions, for which companies would pay. But as the regulations to manage any mining hadn’t been formed these companies were not allowed to do any actual exploration.

There was, however, a clause built into the agreements for mining concessions. This clause allows any contractor granted a licence to announce that they want to start mining and start a countdown clock giving the ISA two years to complete the environmental regulations. If the two years passed with no such agreement made, then that contractor can, in theory, start mining regardless. In July 2021, the Pacific island state of Nauru did exactly this, triggering the countdown.

The ISA was forced to speed up negotiations on how to manage actual mining of the seafloor, from the logistics and the law, to environmental impacts, with a hard deadline to come to an agreement by July 2023. But as the deadline loomed, public attitudes shifted, talks stalled and the deadline passed without an agreement.

‘Some countries are now calling for a precautionary pause,’ says Muriel. ‘There are these train tracks towards exploitation regulations, and some countries are now asking why are we even going in this direction anyway? We are progressing towards exploitation before we know if that is worth doing or a good idea in the first place.’