The answer is fairly simple – consumer demand. Depending on the environment (abyssal plains and seamounts), different metals can be found including, manganese, copper, lithium, cobalt, and others – all taking thousands to millions of years to accumulate. These metals are necessary in the creation of many modern day advances, like computers, cellphones, and renewable energies. With our growing reliance on technology, and ultimately increased production, we would need access to these deep-sea sites in order to sustain demand.

What is the ISA?

The ISA was created to regulate and control deep-sea mining in the high seas. The high seas are ocean territories which are beyond areas of national jurisdiction – meaning no State has authority over the found resources. In order to deep-sea mine, a State or private company has to first be approved for an exploration contract by the ISA, which lasts for 15 years, and thereafter be approved for an exploitation contract. All five sites have already been approved for exploration, and in the near future, as the 15 years is coming to a close, States and companies will be able to apply for exploitation contracts.

Reasons for concern in relation to deep-sea mining have previously, and almost exclusively, focused on benthic species, as they would be the most directly impacted. However, this is not just an issue of the deep-sea – the possible environmental implications will start at the ocean surface and trickle down to thousands of metres.

Beginning at the collision of our two worlds – boat traffic will increase dramatically in these mining sites, which raises concern for cetacean-vessel strikes. Known migratory pathways already conflict with some of the mining sites, and all mining sites overlap with known habitats of cetaceans. It is also very important to note that many movement patterns of cetaceans remain unknown, and thus there could be potential conflict we are presently unaware of.

With an increase in boat traffic, also comes an increase in noise pollution. Sound is vital for cetacean communication, navigation, and feeding. This impact will ultimately be intensified with sounds of the actual mining equipment – which includes the use of sonar systems. Although this will impact all cetaceans, it will be especially detrimental for toothed whales which rely on echolocation for feeding. Echolocation is essentially biological sonar, in which toothed whales (and other animals) emit a call that returns back to them after reflecting off their surroundings. Beaked whales have been found to be the most susceptible to sonar based on past studies because their behavioral response to sonar is to dive deeper down. However, after these deep dives, they are then forced to return to the surface at a faster rate than usual, and can acquire decompression sickness, commonly known as “the bends”.

Seamount visitation has been documented in humpback, sperm, sei, northern right, blue, and multiple species of beaked whales. We do not know exactly why seamounts appear to be important habitats for cetaceans, however, one theory is that they are stopover feeding grounds during migrations. If this is correct, seamount mining will not only potentially impact cetaceans’ food source, but the sediment plumes created could impede their hunting capabilities. It is difficult to predict how long these sediment plumes could remain suspended, but they could be potentially long-lived based on slower ocean currents found in the deep ocean. Furthermore, important feeding grounds may not only lay near seamounts, but also the abyssal plains. Recently, over 3,500 depressions were found at over 4,000 meters in the Clarion-Clipperton Zone – these match patterns of foraging beaked whales that consume their prey via suction.

Although very little research has been conducted, it is theorized that cetaceans could be using seamounts, as well as other magnetic ocean structures, as geomagnetic cues during migration. Other species, like fish and birds, are known to contain biomagnetite, and it is possible that cetaceans contain it as well. Biomagnetite is likely to be used as an internal compass for migratory animals, that is triggered by the magnetics of the planet. Further research is needed, but it is possible that cetaceans are drawn to magnetic anomalies, like seamounts, not only for previously stated reasons, but also because of the magnetic pull. This is potentially how cetaceans are able to navigate their way in finding seamounts, a small feature in comparison to a vast ocean. Furthermore, it could explain how cetaceans, like humpback whales, are able to find tropical breeding grounds which can be very small volcanic islands. Thus, it could be reasoned that if mining were to occur, cetaceans might not be able to locate mined seamounts, or navigate in the ocean as successfully because the metals had been removed.

“We know more about the surface of the Moon and about Mars than we do about the deep-sea floor…” –Paul Snelgrove, Marine Biologist.

This is precisely why, if deep-sea mining is to proceed, it should be done with extreme caution and hesitation.

The era of deep-sea mining may be unavoidable due to our modern day dependence on technology. Although, it is critical as we progress forward that all species of the ocean are considered in relation to deep-sea mining. Benthic organisms will perhaps be the most directly affected by mining, however cetaceans’ and other pelagic species’ wellbeing will not necessarily be preserved. It is extremely important when making any environmental decisions to take into account all members of the ecosystem.

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