Deep-Sea Mining

The deep sea begins at a depth of 200 meters, the point at which almost no sunlight passes through the water. Only a small amount of blue light penetrates through the water column, making the deep sea – aside from the bioluminescent glow of some creatures and volcanic light – rather dark. The water temperature is also quite cold, with an average of only 4 °C and the pressure is 20 to up to 1100 times the pressure of Earth’s atmosphere. The deep sea encompasses more than 95% of the ocean’s volume – making it the largest habitat on Earth!

Deep-sea mining is a process to remove mineral deposits from the ocean’s seabed. These minerals are often in the form of polymetallic nodules – rock-like nuggets rich in rare metals as nickel, cobalt and copper. These metals are in high-demand to support battery production for the global shift towards electric energy. They are crucial components for electric cars and electric energy plants. 

To extract the metals, mining companies would need to lower down robotic vehicles to scoop or suck up the nodules, then pump them up to a ship waiting at the surface. There are different strategies and designs for how to do this, some companies are even working on precision extraction techniques that promise minimal environmental impact. However, many marine scientists and deep-sea experts strongly disagree.

Polymetallic nodules are rock-like mineral formations that are mostly comprised of manganese and iron-oxide (you might even hear them referred to as (ferro-)manganese nodules). These nodules initially form around another object – like a clam shell or a shark tooth – and grow by absorbing metal compounds from ocean water. They grow incredibly slow – it takes about a million years to form one centimetre of diameter.

Nodules are also an important habitat for deep-sea animals and thus home to a unique biodiversity. The deep-sea floor is made up of sediments that tend to be more like ooze rather than a hard surface, that is, except for the nodules. These make up the only solid surface for thousands of kilometers and thus are critical attachment points for a variety of hard-surface-dependent creatures like anemones, sponges, corals and nematode worms.  Even creatures who don’t attach directly to their surfaces sometimes rely on nodules – like a species of octopus that has been observed depositing its eggs onto specific sponges that only grow on polymetallic nodules.

These nodules exist in all oceans, but there are a few areas – like the Clarion-Clipperton Zone – where they occur in high enough density for deep-sea mining to be profitable.

The metals in polymetallic nodules are in crucial to support battery production for the global shift towards electric energy – that’s why you might hear that deep-sea mining is part of the sustainable solution to switch to alternative energies. Indeed, the cobalt, copper and nickel found in the nodules are crucial components for energy storage in technology like electric cars as well as electric energy plants. In efforts to reduce global consumption of fossil fuels, a global shift to electric energy increases the demand for batteries to store this energy and thus the components within them. But while wind and solar might be renewable, the polymetallic nodules needed for batteries are not. The nodules grow incredibly slowly – only 1 cm in diameter every million years. Once they are gone, we can’t expect to see new nodules for millions of years.

Depleting non-renewable nodules isn’t the only unsustainable aspect of deep-sea mining. The process of mining creates extensive and irreversible damage to ocean ecosystems, including:

• Removal of nodules removes important marine species habitat – resulting in species extinction. Scientists estimate that around 18% of species would disappear if we were to move forward with deep-sea mining.
• Mining produces sediment plumes both near the sea bed as well as further up in the water column (from waste-water discharge) that would suffocate and smother animals, disrupt photosynthesis and stir up toxic elements. All of these things will impact the intricate marine food web that humans also rely on.
• Mining would create large-scale disturbance of sequestered carbon stored in the sediment as well as the bacteria and animals involved in the storing of carbon. This re-introduction of carbon could exacerbate climate change.

Can destroying huge swaths of the world’s largest habitat be sustainable? We don’t think so.

Nodules exist in all oceans, but there are only a few areas – like the Clarion-Clipperton Zone – where they occur in high enough density to be prospects for deep-sea mining. The Clarion-Clipperton Zone (CCZ) is an area in the Pacific Ocean between Hawai’i and Mexico that encompasses about 9 million square kilometres – roughly the size of Europe! The reason it is often the subject of deep-sea mining news is because it is the largest deposit of polymetallic nodules, with densities up to 75 kilograms per square meter and an estimated total mass of around 21 billion tons.

 

Because it lies in international waters, the CCZ is managed by the International Seabed Authority, a council responsible for developing regulations for deep-sea mining. Some countries are eager to exploit the deep-sea, while others (now 21!) support a ban, moratorium, or precautionary pause on deep-sea mining. These disagreements have put regulatory talks on hold until 2024.

Studies show that that damage caused by deep-sea mining would be both extensive and irreversible.

Damage from deep-sea mining will impact ocean species, marine ecosystems, global climate and ultimately humans. Here are just a few ways, but the ocean is a complex and interconnected ecosystem, the full impact is still largely unknown.  

Polymetallic nodules provide the basis to form marine life. Removing them from the ground leads consequently to the removal of species that live on them – approximately 18% would disappear.

Machines used to collect polymetallic nodules from the sea floor have been shown to stir up sediments, creating a plume that smothers and suffocates animals living on the ocean floor as it slowly starts to settle. Sediment plumes are also created from wastewater which is pumped back into the ocean, further up in the water column, after the nodules have been collected and rinsed at the surface. These wastewater plums spread sediment over dozens of square kilometres impacting not only the benthic creatures (animals living on the sea floor), but the ones living in the water column as well. Gills and other organs of fish, squids or jellyfish may become clogged, transparent organisms like salps or larvae become visible again to their predators. The sediment also contains toxic metal compounds, which poisons the food chain of the all organisms for many years – including our own.

Studies show that that damage caused by deep-sea mining would be both extensive and irreversible.

Damage from deep-sea mining will impact ocean species, marine ecosystems, global climate and ultimately humans. Here are just a few ways, but the ocean is a complex and interconnected ecosystem, the full impact is still largely unknown.  

Alliances against deep-sea mining are growing – scientists, economists, environmental organizations and even big players in the automobile industry are publicly voicing their disapproval or calling for a ban of deep-sea mining. Yet, there are still countries and companies eager to exploit our oceans. 

So what can we do to protect the deep sea and its unique and valuable species?

1. Encourage political decision makers to stop deep-sea mining, especially without strict and scientifically-informed regulations in place. Go to Defendthedeep.org to easily click a tweet to your national representative. 

2. Talk about the deep sea – with friends, family, colleagues- the more we know and understand something, the more we value and protect it. Help build that understanding and value of the deep sea with those closest to you! Also follow, comment and spread #DefendtheDeep, #NoDeepseaMining and #StopDeepseaMining on your Social Media accounts to help raise the public awareness.  

3. Support organizations or campaigns that are working to study and protect the deep sea and ocean species. Consider donating your time or money to these important causes.