How low can we go? The importance & impacts of deep sea mining

Written by Jenny Hickman

For centuries, the high seas have been a place of exploitation and misuse. The “out of sight, out of mind” attitude that pervades offshore activity has resulted in the ocean becoming steadily depleted of fish stocks and filling up with anthropogenic waste. For far too long it was believed that the ocean was too big to be damaged by human activity and that whatever we took out or put in would ultimately make no difference to the barren and empty world thousands of fathoms below.

oil rig
We have been mistreating our oceans for centuries, is deep sea mining the next on the list?

These days of course, we know differently. Although still so much of our oceans remain unexplored and undiscovered, we have learnt enough to know that the deep sea is far from barren and empty. It is not the great dead zone we once believed it to be. We now know that not only are the deepest parts of the ocean brimming with life, it is believed that it is within these depths that all of life on earth began, forming around deep sea vents, gradually migrating towards the surface and on to land. We know that life at the bottom of the sea is more bizarre and alien than any we have seen before, and that we have not even begun to understand it yet. We know that now is the time to show the deep sea the respect and attention it deserves.

So why now of all times are we looking to exploit it? Unfortunately, the same conditions which provide deep sea organisms with an environment in which to thrive, have also created huge quantities of materials which are increasingly valuable to humans. As superheated waters billow into the sea from beneath the Earth’s crust, deposits of metals, minerals and rare-earth elements have formed around them. Which has created environments rich in sulphide deposits, metallic crusts and ferromanganese nodules, all of which are as important to deep sea organisms as they are to us.

hoovering nodules
A giant ‘hoover’ vacuums up valuable ferrmanganese nodules from the seafloor

It is because of these valuable deposits that we are currently teetering on the brink of an extensive new mining industry. Major companies have already been created with huge financial backing and the race to beat the rest to the deep sea treasures is quickly intensifying. Gigantic machines designed to hoover up the seafloor are already being built and their deployment is imminent, but what are the implications of their activity going to be?

Realistically we don’t know the full scale of the impacts this new industry could have. However, what we do know is that the deep sea is a unique environment which is largely free of disturbance. This is very important, as when an environment is subject to frequent natural disturbances, such as the pounding of waves on a rocky shore or periodic fires in a forest, the organisms within the ecosystem are adapted to survive and the ecosystem as a whole will develop resilience. The deep sea is an environment which remains hugely undisturbed and therefore is not likely to bounce back from such disturbance.

The gigantic mining equipment ready to get to work on the seafloor

The sediment layer grows achingly slowly as tiny specs of “marine snow” drift down through the water column over hundreds of years. The sediment is soft and light, it is not coarse, grainy and heavy like the sediment we see in shallow water. The animals which live here may be suspension or filter feeders, burrowed into the soft floor exposing only the delicate appendages designed to catch food and provide oxygen. Survival under such crushing pressures also for most organisms negates the feasibility for protective skeletons or exoskeletons, meaning many creatures are soft bodied and vulnerable.

When large machinery passes over this environment, not only will the creatures directly in its path be crushed, but the sediment layer, which has taken thousands of years to form and contains so much deep sea fauna will be removed. Sediment around the vehicle will be thrown up into the water column and redeposited elsewhere, at a rate significantly higher (it is believed it could be as much as 300% higher) than normal sediment deposition rates. The plumes in the water column could extend for hundreds of miles and the fragile creatures which survive here could find themselves smothered, unable to gather food or reach oxygenated waters.

So, with all this in mind, why should we let this go ahead? Well, this is where it gets tricky. The materials we are gathering from the seafloor are all so valuable because they are required to meet the increasing demand for new technologies, including renewable energy, mobile phones, satellites and electric cars. As much as I am a conservationist at heart and my gut instinct is to protect these environments and the incredible life that lives here, I am also a realist. The human race will persist, and whilst we persist, we will develop. Unfortunately this means we cannot exist without utilising the natural environment to some extent. It is a bitter pill to swallow, but nothing in this world comes without a price.


grab claw
A large piece of a metallic deposit is removed from the seafloor

The good news is that this new mining activity has arguably had more investigation in to impacts than any previous large-scale resource gathering. In previous years we have indiscriminately exploited the environment with little to no attention paid to the impacts we have. More than ever, the mining industry is being forced to understand the impacts of their activities and to attempt to mitigate them. The International Seabed Authority (ISA) is the main organisation tasked with regulating mining activities. It has so far granted 29 licences for companies to begin exploratory work on seabed mining, with a heavy focus on the Clarion Clipperton Zone (CCZ), a nutrient rich expanse of seabed in the Pacific Ocean.

However, the ISA has also come under scrutiny for some of the decisions it has made. As part of the license application process, companies must undertake scientific surveys to assess the damage their activities will cause. Many researchers believe that the quality of these surveys is highly questionable and often inadequate, as well as often being completely funded by the companies applying for the licenses in the first place. This is all overlooked by the ISA who themselves are something of a paradox, because of their duel responsibilities to both preserve and sustainably exploit the seabed at the same time.

In addition to this the ISA only has authority over international waters and not in any individual countries exclusive economic zone (EEZ). Granted most deep sea mining will take place out in deeper international waters, but countries are still free to exploit their own sections of seabed or sell the rights to do so to big multi-national corporations.

removing minerals
Sulphide deposits surrounding deep-sea hydrothermal vetns, a key marine ecosystem, are destroyed

Deep sea mining is happening, imminently. But the question remains, have we done enough? As usual, the economic gains push with far more weight than the environmental losses. So, have we done enough to be sure we are not causing irreparable harm to an environment we haven’t even begun to understand? It is not too late to act with a conservation mind and I hope that we use this opportunity we have to finally act for the benefit of both people and the environment. In 2020 especially, we have seen with chilling clarity what our maltreatment of the natural world can do. With a combination of hindsight and science we have learned that it is possible to live more sustainably and harmoniously with the natural world. I can only hope we have the foresight to do so.

Jenny is currently studying Marine Biology and Coastal Ecology at Plymouth University, with a keen interest in ecology and biodiversity. Jenny believes reconnecting people with nature is vital to conservation and previously spent ten years working in environmental education and charity management. You can find her on instagram (@hickman.jenny) and linked in here.

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