An eco-friendly strategy for undersea mining

Interest in deep-sea mining is growing and several nations are exploring the depths to find areas with valuable resources. Before they start exploiting the minerals, tests need to be carried out by places such as the Center for Ocean Solutions to assess the potential damage. The research, it is hoped, will inform those involved in how to maintain a balance between extracting valuable resources and preserving marine habitats.

Cnidaria deep sea mining

On the seabed, jurisdiction can be murky. Just 3% of the world's oceans are protected, leaving the remainder vulnerable to exploitation from industrial fishing, pollution and, before long, mining.

Research institutions are currently conducting studies to try and figure out what the effects of mining will be to deep-sea habitats so rules can be established. One such institution is the Center for Ocean Solutions in the US, which published a paper in Science this year highlighting the rapidly growing interest in subsea mining and the current lack of understanding about its effects.

Demand is ever increasing

A number of factors is driving increased interest in deep sea mining, among them the growing demand for rare earth metals used in smartphones and hybrid batteries, as well as advances in mining technology, says marine biologist Dr David Hughes from the Scottish Association for Marine Science.

"The technological ability to harvest some of these minerals from the seabed has greatly increased," he says. "So I think it's a combination of the potential economic value of some of these rare metals combined with the development of this technology."

"The technological ability to harvest some of these minerals from the seabed has greatly increased."

Currently, some of these rare earth metals are mainly found in mines in China. In 2010, they produced over 95% of the world's rare earth supply. Many industries are dependent on some of these metals, says Hughes, and nations are reluctant to become too reliant on one source.

And when the price of metals is high, it becomes more economically viable to consider extracting them from environments that are difficult to access, for instance at the bottom of the deep sea.

There are three main techniques for exploring minerals in the deep sea - the mining of dead or extinct hydrothermal vents, the collection of poly-metallic nodules, and the scraping of sulphide deposits, which are also found on land.

Each of these resources is found a different environment. The hydrothermal vents are usually in relatively shallow waters at about 1500m deep, whereas the nodule fields are much deeper and sulfide deposits occur along ocean ridges at tectonic plate boundaries.

Concerns of marine scientists

Many of the dangers posed by deep-sea mining are unknown, which is what concerns many marine scientists. The bottom of the ocean is one of the least well understood ecosystems on the planet, and scientists are worried about the adverse effects mining activity could have on vast regions.

The paper by researchers from the Center for Ocean Solutions advises the International Seabed Authority about protecting areas of the ocean before they hand out any more exploratory licences. It also addresses the need for research to go ahead that can forecast what damage may be done by deep sea mining.

Biological oceanographer Dr Craig Smith of the University of Hawaii and other researchers from the Center for Ocean Solutions are conducting research in the Clarion-Clipperton zone. This is an area of the Pacific Ocean where much of the imminent mining is likely to take place if extraction licences are granted in around 15, years when exploratory licences expire. Just some of the countries currently exploring the zone are Japan, Great Britain, Russia, South Korea, China and France.

The goal of Smith's research team is to evaluate the diversity of species in the zone and understand how different species and populations connect with one another. They are also looking at how broadly individual species are spread across the region. Primarily, they want to discover what is down there, as "it's not very well studied and it's a vast region", according to Smith

"Understanding species ranges and population connectivity are fundamental to predicting extinction risk from activities like mining," Smith adds. "If it occurs [mining] will impact very large areas."

Professor Phil Weaver is the co-ordinator of the Managing Impacts of Deep-sea resource exploitation project (MIDAS), which is also calculating the probable effects that deep-sea mining will have on surrounding wildlife.

"We're going to be looking at the geological impacts," he says. "Space that's taken up by the mine itself, the area that's covered, and how that might fit with the local biological communities."

"Understanding species ranges and population connectivity are fundamental."

MIDAS researchers are investigating areas in the north east Atlantic, eastern Pacific, the Arctic Ocean, the Mediterranean Sea and the Black Sea. They hope to determine the biggest impacts and feed into the industry dialogue so that miners have the opportunity to extract minerals while causing the least damage possible.

Destruction and plumes

One effect being investigated is the impacts and toxicity of released sediments in the Clarion-Clipperton zone. Mining the nodule fields in the sea will stir up the sediment or grind the rock and create a plume of material, which will then spread away from the mining area and potentially travel a long way. This is of most concern in poly-metallic nodule mining, as the nodules contain heavy metal elements which have the potential to be toxic.

"It has been stated that these plumes could travel up to 100km or more away from the mine site," says Weaver. "They could smother seabed organisms, or actually poison seabed organisms."

Poly-metallic nodules occur in very deep environments where there background level of sedimentation is very low, and they are not used to receiving large deposits of sediment falling out of the water column. Smith says that the plumes could have a potentially serious effect on suspension feeders, animals that feed on particles in the water column.

"They're going to end up picking up sediment particles instead of food particles," he says. "That will probably inhibit their ability to feed, so the plume effects are big."

Species can also be very primitive at these great depths and usually live in very stable environments, which means they will probably recover very slowly from disturbance. In fact, Smith says that if a habitat is removed it could take millions of years to grow back.

In underwater environments that contain hydrothermal vents, creatures have evolved to survive in hot, highly movable environments. They are unlikely to be disturbed to the same extent as those on the poly-metallic nodules because they have adapted to harsh surroundings. But this doesn't mean mining is without its downsides here, explains Hughes, particularly for marine animals such as dolphins and whales that have sensitive hearing.

"There's also an issue with noise," he says. "It would involve a robot cutting and grinding away at these vents, which would be a very noisy process probably."

Weaver stresses the importance of not generalising the consequences of underwater mining. The ecosystems that are of interest are all entirely diverse from one another, and thus will react to falling deposits or disturbance differently.

Who owns the sea?

Currently, countries can mine in their Exclusive Economic Zones. Within these boundaries, each nation is responsible for regulating any mining that goes on, and is free to exploit its resources as it pleases. For example, a Canadian mining company called Nautilus Minerals has permission to start extracting copper grades from the seabed off the coast of Papua New Guinea.

Anything outside of those zones is known as "The Area", which is described as a "common heritage of mankind", meaning it belongs to everyone on earth. It is supervised partly by the United Nations Convention on Law of the Sea, which countries sign up to. In doing so, they agree to be overseen by the International Seabed Authority which hands out exploratory licence to countries and companies that apply for them. With this licence, countries can explore their block of the sea for up to 15 years.

Hughes believes that even though deep sea mining is probably inevitable, there's reason to be positive.

"In none of these cases is there a headlong rush to dive in and get these deposits mined and to hell with the consequences," he says. "There are very few countries in the world I think that can afford to completely ignore environmental concerns."

Hughes adds that nations have an opportunity that they didn't have before, which should be taken advantage of. "It's not often really that we've had the opportunity to do this," he says.

"There are very few countries in the world that can afford to completely ignore environmental concerns."

On land, the typical pattern has been to start the process of exploitation such as mining or deforestation, and deal with the consequences afterwards. But research projects that are going ahead to try and predict the impacts of deep sea mining gives researchers optimism that it will be done correctly.

"I think we're kind of ahead of the game a little bit in the deep sea," says Smith, agreeing that deep sea mining policy will probably benefit from the prior investigations. "We're already worried about environmental management and protecting biodiversity ecosystem function before the extractive activities have begun. But that doesn't mean that we'll get it right."

For Smith, the important thing is that environmental baseline studies are done properly, so it is clear what lives there and what might be impacted.

"I think we're moving in the right direction," he says. "But I think we still have a long way to go for deep sea mining."

All mining has a consequence, Weaver points out, and so organisations and mining companies "need to tread carefully" because ultimately, the true impacts of mining on deep sea habitats won't be known for sure until it happens.

"We will only begin to learn those as some mining begins to take place," he says. "Until someone actually starts doing it there will still be some uncertainty as to how responsibly it can be done."