For several years, States have embarked on an exploration of the seabed, immensely rich in precious metals, soon technically ready to be exploited. A new industry that...

Deep-sea mining: "we can't talk about sustainable exploitation anyway"

Rimicaris exoculata shrimp aggregate at a hydrothermal site.

Seemingly inert and useless, these areas of mineral deposits several hundreds or thousands of meters under water, in reality contain fragile ecosystems whose functioning is still unknown.

Text by: Géraud Bosman-Delzons Follow

13 mins

For several years, States have embarked on an exploration of the seabed, immensely rich in precious metals, soon technically ready to be exploited.

A new industry that would come to disturb the world of silence, yet essential in the regulation of the climate.

The One Ocean Summit, organized in Brest from February 9 to 11, must lay the groundwork for regulating the ocean to better protect it... and exploit it “sustainably”.

Shedding light on mining issues with Pierre-Marie Sarradin, chemist and specialist in seabed ecosystems at the French Research Institute for the Exploitation of the Sea (Ifremer).

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RFI: The resources of the seabed are arousing growing desire, as an alternative to landmines.

What do we find in these abysses and in which area of the globe?

Sarradin:

This interest in underwater mineral resources actually dates back to the 1960s, with a more particular interest in polymetallic nodules (discovered in 1868).

These nodules have the shape of small potatoes about ten centimeters in diameter.

They are formed by the precipitation of metals present in seawater over thousands of years.

They therefore contain metals such as manganese, iron, copper, nickel, cobalt, as well as rare earths such as lithium.

These nodules are found in vast abyssal plains, very deep: between 3000 and 5000 meters.

Currently, the most studied area, where there are the most exploration contracts, is the Clarion-Clipperton fracture zone in the Pacific.

Second type of resource: hydrothermal (or polymetallic) sulphides.

This time, we are at the level of the

oceanic ridges

where hydrothermal sources eject a fluid enriched in metals which will, over millions of years, fall and form massive sulphides.

And there, we have mainly iron enrichments, with zinc, copper and rare metals such as gold, silver, indium and germanium.

The sulphides form insignificant massifs of the order of one km² only.

These deposits are found between 800 and 5000 meters deep.

The last resource is the cobalt-rich crusts that we will find on seamounts.

These plates a few centimeters thick are formed in areas of currents that will bring these metals.

These crusts are between 400 and 4000 meters deep and are composed of manganese, cobalt or platinum tellurium, titanium or tallium.

It is the least explored resource and to exploit it, it would be necessary to tear these plates from these seamounts.

Three types of geological structures are favorable for mineral resources.

These minerals are precious both for our current consumption needs but also to ensure the energy transition...

This is the great paradox.

All these metals are essential for the manufacture of electronic devices: mobile phones, computers, batteries, semiconductors... But we also need to go and exploit the deep sea - at least this is one of the solutions - to ensure the energy transition and fight against climate change, for the construction of wind turbines, electric car batteries, photovoltaic panels...

What is France's place and Ifremer's role in this new gold rush?

France is one of the pioneering countries in the exploration of nodules in particular, from the 1970s-80s, in the Clarion-Clipperton zone.

We were also the first to request an exploration contract for this nodule zone, more than fifteen years ago.

Ifremer manages, for the French State, the two exploration contracts that France has: the first on the Clarion-Clipperton Pacific zone [south-east of Hawaii, on an area of 75,000 km², since 2001 , Editor's note] and the other in the North Atlantic, on the ridge for polymetallic sulphides [10,000 km²].

We have several obligations: to assess the resource (the tonnage, the richness of these minerals);

assess the ecosystems that are associated with these resources and the potential impacts;

and possibly assess the economic feasibility of exploitation.

Indeed, several threats to underwater biodiversity close to these deposits have already been clearly identified.

What are they ?

The difficulty is that we are able to identify these impacts but not to quantify them.

And it's not just Ifremer: this lack of knowledge is the subject of an international consensus.

The first, direct impact is the disappearance of ecosystems that we still know very little about.

Why, on land, do we stop construction on land because we come across a protected species - a snail, for example, whose role in its environment science knows - and we wouldn't do it at the bottom of the sea?

If you remove the substrate, the support of the deposits if you will, you remove the whole ecosystem that is linked to it.

Will this lead to the elimination of particular species?

At what scale of space can we work?

At what time scale will ecosystems be able to regenerate, if at all?

We don't know exactly yet.

The second threat is the creation of clouds of particles and sediments.

Indeed, when a machine will scrape the ground, a massive sulphide for example, it will form a plume of sediment.

Several consequences to this.

First, it will be exported by the currents: who knows how far?

This plume will potentially smother filter-feeding organisms in adjacent areas.

Then, as they fall, the particles will transform the ocean floor around the mined area.

Moreover, certain metals contained in the sediments can be toxic once dissolved in water.

Discharges of toxic waste therefore risk impacting surface water.

Third impact, these mining machines will bring noise and light.

We are increasingly interested in noise as a means of communication for marine ecosystems, such as coral reefs: for them, it is a means of finding their food, of situating themselves in space, of finding areas to colonize. , etc

If we add noise, we will perhaps disrupt the functioning of ecosystems, which we do not yet know enough about.

Similarly, fish need darkness to hide or stalk their prey.

Finally, the last potential impacts would be linked to accidental phenomena due to the presence of ships.

The ocean is the great climate regulator on the planet.

It retains carbon and releases half of the oxygen we breathe.

Could this exploitation disrupt this regulation?

For example, by releasing sequestered carbon.

Indeed, this may be one of the hypotheses to be verified.

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Why are these threats not enough to stop any attempt at exploitation?

If we are asked the question of exploitation tomorrow, our position at Ifremer will be to say that we do not yet have enough information to progress to exploitation.

In the event of exploitation, the impact will be there, that is clear.

As with all extractive activities.

On such exploitation of resources, with a renewal over geological time, ie millions of years, we cannot speak of sustainable exploitation, in any case.

The ocean is likely to be impacted up to the surface, with a possible effect including for seabirds.

Our very limited role is to ensure that the environmental impact is as low as possible.

But it is not enough to speak of impacts.

The challenge, once they have been listed, is to quantify them, in order to find acceptable thresholds so that the ecosystems do not disappear.

If we deploy a few tenths of a millimeter of sediment on an environment, there may not be any consequences.

What about several centimeters thick?

We are in complicated environments, deep and difficult to access and where it is difficult to experiment and quantify the potential impacts.

When is what you do irreversible?

If you have 200,000 km² of nodules and you exploit “only” a quarter of them, do you significantly modify your environment, to the point that it no longer works?

It is this tipping point that

The researchers take a delicate position: rather favorable to exploration since any knowledge of the poorly known ocean is good to take, precisely to protect it, but do not comment on exploitation.

However, from exploration to exploitation, there is only one step...

The position, if it is delicate for us, it is in the emergency.

There is a lot of talk in scientific publications about “adaptive management”.

That is to say that if, in five or ten years, mining takes place, it will be necessary to ensure that the regulations adapt to the knowledge that is accumulating and which will perhaps vary from here about ten years.

So for us, exploration means first acquiring fundamental knowledge about the functioning of the deep ocean and associated ecosystems.

But the time of industry is faster than that of scientific research.

Two companies, Belgian and Canadian, have already entered the extraction test phase...

It's true that when you see their development plan over the next five or six years, it can go very quickly.

Moreover, Ifremer took part in the independent campaign which aimed to assess the impacts of this pilot test.

And what impacts have you been able to establish: is there damage?

This project is very recent.

The data is being processed.

But we can clearly see that we have gone from something that was technically difficult five years ago to something that is possible within five or ten years.

Japan has carried out trials in their EEZ [national waters, editor's note] and indeed exploitation could start in an EEZ and not in the international zone.

Some experiments were carried out on nodule fields in the 70s and 80s.

Forty years later, their ecosystem has not yet fully recovered from these disturbances...

This map from the International Seabed Authority shows the different areas of exploration in international waters.

It has so far issued some thirty exploration contracts - none for exploitation - to countries or groups of countries.

France has two, in the Pacific and in the Atlantic.

When will science be able to position itself on this subject and what are the next steps?

Difficult to say because we are progressing slowly given the complexity of access to these areas.

The exploration license for the Clarion-Clipperton nodule zone has just been extended for five years.

On the sulphide contract, we had a campaign last year for the evaluation of resources and we should have a campaign in 2023 or 2024 to understand the functioning of ecosystems.

We are also working, either internally or via European programs, on methodologies for monitoring the impacts of scientific activities.

And if science were to recommend saying "no" to exploitation, do you think that its opinion would weigh against the pressures of governments, industrialists and the needs and desires of consumers for technological products?

For other resources, such as oil or land mines, exploitation took place before the impacts were known.

Today, we are in a slightly less bad situation insofar as we ask ourselves the question of the impacts before starting operations.

This is where we, research institutes, have a role to play and not hide behind a “we don't know so we can't go there”.

It is absolutely necessary that we provide answers.

Afterwards, we are certain that the message that we will send as Ifremer scientists will be heard.

That said, when we see what has been done on the climate for 40 years, unfortunately, science cannot put a brake on it since it is not listened to.

When the manufacturers have decided to go there, we will be completely overwhelmed.

All eyes are on the scientists.

Do you feel, at Ifremer or individually as a researcher, pressure in the face of these issues

Don't shoot the messenger.

But one has the impression that there is only one alternative which prevails, that it would absolutely be necessary to seek these mineral resources of the great funds.

When in fact there are other conceivable paths: isn't energy or consumption sobriety also a solution?

The recycling ?

The finer analysis of everything relating to the life cycle of materials?

This is a personal point of view.

My role as a researcher is to provide answers to questions about impact assessment and make this data public.

At Ifremer, we have exchanges on the ethics of scientists and collaboration with industrialists: how to work with them and not for them, how to maintain total freedom in the publication of research results?

We constantly try to keep our right to publish when we work with manufacturers, without the right of veto for these collaborators.

That's the ability to say no that you were talking about.

This is to maintain a good reputation in the research world.

These pressures may have been felt in the past and we are increasingly aware of this.

Our international colleagues also have this kind of pressure.

Could Ifremer be given an operating mandate and find itself judge and jury in some way?

We put the question to our management and it's clearly no: Ifremer will not participate in operating contracts.

As soon as the exploration contracts become exploitation contracts, they will be transferred to manufacturers.

We will thus be able to maintain our independence and continue to work on monitoring the long-term impacts.

Active smokers in the Lau Basin (Tonga Islands, Southwest Pacific).

The chimneys on the left are mainly made of sulphide of zinc, copper and highly concentrated in gold.

Deep-sea mining: "we can't talk about sustainable exploitation anyway"

Deep-sea mining: "we can't talk about sustainable exploitation anyway"

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