CREATURES OF THE DEEP

Deep-sea mining is contentious for many reasons – economic, political, financial, social, and environmental, to name a few. One research team at Southampton is honing in on the environmental impacts.

Humanity is still a long way from discovering all the habitats in the deepest depths of our planet’s oceans. If we do not know exactly what is there, how can we protect it if deep-sea mining becomes a bigger industry?

It is an area of interest for Jon Copley, Professor of Ocean Exploration and Science Communication, who devotes his work to understanding the environmental impacts of deepsea mining.

Jon outlined the three deep-sea habitats researchers are focusing on – home to the three mineral resources that are of interest: seafloor massive sulphide (SMS) deposits, manganese nodules, and cobalt-rich crusts.

Seafloor massive sulphides (SMS)

These form next to deep-sea hydrothermal vents.

Back in 2013, Jon led the first HumanOccupied Vehicle dive to the world’s deepest known hydrothermal vents, becoming the first British person to dive more than 5,000 metres.

“Habitats next to active vents are home to over 400 species of animals that are not found anywhere else on Earth,” said Jon. “They are globally rare habitats, home to creatures such as metre-long tube worms, swarms of blind shrimp, and scaly-footed snails.”

The total known area of active hydrothermal vent deposits is less than 50 square kilometres worldwide. “The idea of strip mining such a small area on land would be a total nonstarter, so a big concern of ours is to get protection for active hydrothermal vents and their active biodiversity, as these systems are extremely vulnerable,” said Jon.

Mining an inactive vent, however, would be a different story. “Vents are active for a period of time – it could be a few decades, it could be thousands of years – but at some point, they shut down and the animals that depend on the mineral-rich fluids die out,” explained Jon. “The impact of mining inactive sulphides is very different and could well be manageable. The big question, however, is at what point does a vent become inactive? They often look inactive but then there is a tiny bit of activity – so the thresholds on inactivity need to be set.”

Manganese nodules

Manganese nodules are prolific in the underwater world. They grow very slowly, forming over thousands of years, on the surface of underwater plains. Manganese nodules have been known about for a very long time, since HMS Challenger dredged them up from the Eastern Pacific in the 1870s.

Jon said: “Manganese nodules are prolific, and are an area of scientific excitement. In some places, they carpet the seafloor.”

In one area within the Clarion-Clipperton Zone, between Hawaii and Mexico, manganese nodules cover the seafloor over an area spanning 1.5 million square kilometres.

The International Seabed Authority has already set aside protected areas where there will be no mining. But Jon said: “Research is required to refine whether these protected areas are in the right places, and are representative of the species populations. Are the same species scattered throughout nodule fields, or are there pockets of rare species? Scientists continue to work to understand the patterns of life.”

Cobalt-rich crusts

Cobalt-rich crusts form on seamounts, which are home to very different marine life from hydrothermal vents because they are rocky.

“They are home to slow-growing corals and sponges,” said Jon. “These are vulnerable if the cobalt crusts are scraped off the sides of seamounts – they will be scraped off too. But, their areas of habitat are much bigger than active hydrothermal vents, so they are potentially more widely distributed, and therefore less vulnerable.”

Current projects

Jon is working on two deep-sea projects, SMARTEX and DEEPEND.

SMARTEX (Seabed Mining And Resilience to EXperimental impact) is investigating the ecological environmental impacts of manganese nodule mining. An expedition to collect samples from the Pacific took place in early 2023, and a second expedition will run in 2024. The project involves nine institutions and is funded by the Natural Environment Research Council.

DEEPEND (Deep-ocean resources and biodiscovery – enabling a sustainable and healthy low-carbon future), funded by the DEFRA Global Centre on Biodiversity for Climate, is exploring the biotechnological potential of deep-sea biodiversity, including examining manganese nodules.

“This project is about biodiscovery: guiding people to where there might be natural products of interest for the future,” outlined Jon. “DEEPEND is investigating compounds of potential pharmacological interest – things like new treatments to overcome antibiotic resistance – and looking at compounds produced by animals.”

Southampton’s involvement in DEEPEND includes producing a roadmap for biodiscovery, to guide future exploration. It will show where species and compounds live, to inform future research into what is found where in the deep ocean.

Chemical Reactions

Research led by Rachael James, Professor of Geochemistry, is investigating a hydrothermal field of seafloor massive sulphide (SMS) deposits in the Atlantic that is rich in metals.

The project team has completed one expedition to the Mid-Atlantic Ridge, to the Semenyov Hydrothermal Field, to drill through the SMS deposits to find out what controls the metal concentrations within them. To do this, they need to understand the chemical processes that occur as the deposits form.

“The interest in this particular site is that the vent fields are located in a peridotite crust, which means that the deposits tend to have higher concentrations of metals including copper, nickel, zinc and cobalt, which are required for clean energy technologies – so there is a need to find more resources of them,” said Rachael.

Electric cars contain around three times as much copper as conventional cars, and substantial quantities of cobalt and zinc are needed for the manufacture of wind turbines. Cobalt is crucial for battery performance.

The first expedition focused on drilling and sampling the sulphide, and capping some of the drill holes. On the second expedition, scheduled over five weeks in October and November 2023, the team will uncap the holes to understand the chemical makeup of the fluid circulating through the sulphide mounds.

Rachael explained: “My interest is in understanding the chemical reactions that are occurring as seawater circulates through the crust and through the hydrothermal sulphide deposits, and understanding the processes that lead to metal enrichment.”

THE DEEP-SEA: WHAT RESOURCES ARE DOWN THERE?

Three mineral resources found in the deep sea are of interest. They are manganese nodules, seafloor massive sulphide deposits, and cobalt-rich crusts.

Manganese nodules:

These are found on underwater plains. They are very rich in manganese, used in steel production, and cobalt, which is required for lithium-ion batteries. They also contain rare earth elements, such as neodymium, which is used in magnets for wind turbines, computers, mobile phones, medical equipment, and toys; lanthanum, which is used in lighting; and gadolinium, which is used in MRI and X-ray.

Cobalt-rich crusts:

These crusts form on seamounts (underwater mountains) and are rich in cobalt and rare earth elements.

Seafloor massive sulphide (SMS) deposits: Deposits primarily of copper, nickel and cobalt that are found by hydrothermal vents in volcanic rifts.

DOSI: SAFEGUARDING OUR OCEAN’S FUTURE

In 2022, Southampton researchers were awarded £3.5 million to provide expert advice on deep-sea matters, from conservation to mining.

The funding was awarded by the Arcadia Fund – a charitable fund founded by Lisbet Rausing and Professor Peter Baldwin – to the DeepOcean Stewardship Initiative (DOSI), a global network of 2,600 experts from more than 100 countries, including colleagues from the School of Ocean and Earth Sciences (SOES).

Dr Maria Baker, DOSI’s Executive Director and Senior Enterprise Fellow in SOES, said: “DOSI’s international ties mean that we are ideally placed to provide the knowledge needed to produce effective policies in both national and international waters. That work is especially important now, as the next decade will be a crucial time for the health of our ocean. With this continued support from Arcadia, we can provide independent science to guide high-level interactions on topics like seabed mining, climate change, biodiversity, and more.”

Find out more dosi-project.org