The race to mine the deep sea has a subtle unsettling quality. It’s not visible to you. No visible scars on a hillside, no protests outside a mine entrance. All of this is happening thousands of meters below the surface, in complete darkness, and under intense pressure, and that invisibility might be the exact issue.
In an effort to create the most comprehensive understanding of the potential effects of deep-sea mining on marine life, a recent review headed by Professor Adrian Glover of the Natural History Museum in London has examined more than 200 published and unpublished reports covering more than 50 years. The results are significant and, in some cases, subtly concerning. According to the review, biodiversity loss in some areas may be irreversible.
Over half of the Earth’s surface is covered by the deep ocean. The majority of it is still unnamed, unmapped, and unresearched. Polychaete worms, echinoderms, crustaceans, and sponges inhabit the abyssal plains, which are enormous, silty expanses of seafloor at depths greater than 3,000 meters. Many of these organisms have not even received scientific names yet. In other places, hydrothermal vents rise sharply from the ocean floor, releasing geothermally heated water and supporting completely independent ecosystems, including tube worms, shrimp, crabs, and snails that flourish in environments that shouldn’t support anything at all. Some of the planet’s most remarkable biological systems might be found in locations we haven’t really explored.
Additionally, those locations are perched atop vast mineral wealth. Hydrothermal vents are covered in copper, cobalt, and gold, while polymetallic nodules scatter like stones across the abyssal plains. The demand for these particular metals has increased as the world moves toward more environmentally friendly technologies, such as batteries, electric cars, and renewable energy infrastructure. The reasoning is nearly circular: one of the planet’s last genuinely unspoiled habitats is buried beneath the minerals required to create a cleaner planet.
Professor Glover was open about a gap that even he was taken aback by. “It is surprising that such a major environmental issue has not yet been comprehensively reviewed in the scientific literature,” he stated. The review, which was published in Current Biology, makes an effort to close that gap to some extent, but it is cautious to point out that the data is still lacking in important areas. Abyssal plains may be able to recover from mining disturbance over a long period of time, although the recovery will only be partial. The situation is less promising for seamounts and hydrothermal vents. The review is straightforward: significant disturbance at active vent sites would be incompatible with biodiversity commitments that the majority of countries have already made in international policy. These environments are home to species that are found nowhere else.
The most actively targeted region at the moment is the Clarion-Clipperton Zone, a six million square kilometer stretch of deep Pacific between Hawaii and Mexico. Between 6,000 and 8,000 species could be found there. There are only 436 names. After describing 24 new crustacean species from deep-sea surveys, scientists at the Natural History Museum and the National Oceanography Centre are attempting to change that. In the most awkward sense of the word, it feels like a race.
The review refrains from endorsing or opposing mining. Because of the intense political and economic pressures in this area, scientists who voice their values too loudly run the risk of losing the room, so this restraint is intentional and probably wise. The team does contend, albeit more subtly but with genuine conviction, that the regulatory framework needs more precise science. The 30% protected area currently set aside in the CCZ sounds significant, and it may be, but as the review notes, there is currently very little information on whether those boundaries will truly protect what matters.
It seems as though the commercial momentum and the science are advancing at different rates as this field develops. The minerals are present. There is a demand. The technology is nearly complete. Our knowledge of precisely what we would be destroying and whether any of it would return once it is gone is still lacking.
