Deep Sea Mining: Out of Sight, Out of Mind?

by |March 12, 2014

Hydrothermal vent tube worms get energy from bacteria that live in their plumes. Photo: Taken in the Pacific Ocean by NOAA’s National Undersea Research Program (NURP)

By Christine Hirt

We are all familiar with some of the movements to protect biodiversity on land, but what about biodiversity in the deep sea? There is 10 times more deep sea (up to 4,000-5,000 meters) than shallow continental shelves (up to 200 meters deep) in the world’s oceans.The deep sea is far from a quiet abyss: Consisting of mountain ranges, canyons, trenches, and seamounts, this stunning underwater landscape is the home to a vast amount of organisms. Biodiversity is often used as a gauge for the health of an ecosystem, since too little biodiversity means the ecosystem might be compromised. The diversity of life in the deep sea can also have major effects on conditions on dry land. Depletion of fish populations, climate change effects, and increased greenhouse gas concentrations in the atmosphere are only a few of the major effects that are influenced by deep sea ecosystems. In order to try and avoid these detrimental effects we can work to protect deep sea environments and sites of high biodiversity.

Hydrothermal vents, although extremely volatile, are home to some of the oceans’ most exotic biomass. Since their discovery, these vents have offered insight into how the ocean chemistry, how the Earth’s surface formed, and even how life may have began. These vents are also the sites of abundant manganese nodules that are composed of copper, cobalt, nickel, gold and other commercially valuable minerals. However, these nodules don’t form overnight. In fact, it takes millions of years for these potato-sized nodule deposits to form. Vast mineral resources like these are found far out in international waters and thousands of meters below the ocean’s surface. Various technological advances in remote sensing, remote operated vehicles (ROV’s), and more have made the extraction of these rich minerals possible, although it is still a costlyand environmentally riskyendeavor.


This hydrothermal vent, named Sully, emits jets of nutrient-rich fluids that create the black smoke. Photo: NOAA

Companies like Nautilus are eager to start mining in these deep sea environments due to dwindling mineral resources on land. These minerals are invaluable in the modern world, and are found in cell phones, computers, building materials and household appliances. Nautilus has stressed its concern about the environmental risks of deep sea mining with its Environmental Impact Statement, Nautilus CARES program, and proposed mitigation strategies. The company reports that the main potential environmental impacts of mining include material and habitat removal, plume generation and water quality distress, and noise and vibration disturbances. Operational strategies aim to reduce the impact on the seafloor environment by designating temporary refugee areas to help excavated areas recover over time, relocating animals from non-excavated areas to places where excavation has been completed, and adding artificial substrates to increase chances of rehabilitation. The mid-ocean and surface environments above these mining sites would also be susceptible to harm. This will be mitigated by additional operational strategies, such as discharging the water contaminated by the mining process. Nonetheless, direct and indirect impacts on vents and nearby communities remain very real possibilities even with these practices in place.

One of the major issues with deep-sea mining is that so little is known about its implications on the environment. Scientists are unable to extrapolate what kinds of populations would be affected by extensive mining because the deep sea is still largely unexplored, and the biodiversity in prospective mining areas so incredibly vast. Scientists at the Lamont Doherty Earth Observatory have discovered new evidence of hydrothermal vents in the Antarctic in the past few years, yet understanding the unique environments around these elusive vents still proves to be a challenge. Due to the lack of knowledge about these ecosystems, no one can say whether they are resilient enough to withstand such trauma. At the recent American Association for the Advancement of Science (AAAS) annual meeting in Chicago, scientists and lecturers were invited to speak about Meeting Global Challenges: Discovery and Innovation. Lecturers included Columbia University faculty and Linwood Pendleton, senior scholar in the Ocean and Coastal Policy Program at Duke University’s Nicholas Institute for Environmental Policy Solutions. Pendleton, as part of a panel on deep sea ecosystems, touched on policy issues: “We know a lot about a few places, but nobody is dealing with the deep sea as a whole, and that lack of general knowledge is a problem for decision-making and policy.” These questions only add to the difficulty of creating regulations regarding deep sea environments.


Vibrant colonies of tube worms thrive on this vent which is predominantly composed of iron- and sulfur-bearing minerals. It is located in the hydrothermal field on the Juan de Fuca Ridge. Photo: NOAA

Regulating deep sea mining has proven to be an onerous task for scientists, mining companies and policymakers alike. One area of mining interest, the Clarion-Clipperton fracture zone, is about 500 miles southeast of Hawaii and 5,000 meters below the ocean surface. Enforcing regulations—or even knowing what regulations to put in place—is extremely difficult there because the zone crosses political, geographic, and disciplinary boundaries. The International Seabed Authority (ISA), formed by the United Nations Law of the Sea, is in charge of developing the regulations for exploration and extraction while also establishing and enforcing the preservation of areas that will be impacted by mining. They have expanded the marine protected area network to cover 24 percent of the 6 million square kilometers that comprise the Clarion-Clipperton zone management area, representing a major marine ecosystem-based management success using a spatial approach. Despite the conservation groups’ recent successes protecting some deep sea ecosystems, mining companies are still preparing for the difficult dive down to these unforgiving, yet lucrative, environments.

Nautilus estimates that if only half of potential sulfide-rich deposits are geographically viable for mining, they could produce several billion tons of copper per annum, a considerable amount compared to the copper content of 19,000 tons from total land mining production in 2012. Nonetheless, oceanographer Craig Smith from the University of Hawaii warns that when mining begins in the Clarion-Clipperton zone, it is likely this massive project will create the largest ecological footprint of any single human activity on the planet. Although deep-sea mining is virtually inevitable, mining in a sustainably conscious way with efficient deep-sea management practices in place is the best solution to each of the stakeholders’ concerns. The race is on to create more progressive, environmental regulations, but much more scientific research is necessary to understand how to best regulate these ecosystems.

Peter Rona, the oceanographer who accidentally discovered hydrothermal vents, recently passed away this February at the age of 79. He described science as detective work, “It’s about racking up one clue after another.”

Christine Hirt is the marketing and communications intern at the Earth Institute Center for Environmental Sustainability. She is majoring in environmental studies with a concentration in earth science at the Macaulay Honors College at Hunter College. Her main interests include hydrology and coastal oceanography. Her favorite deep sea creature is the blob sculpin

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