ENVIRONMENT

Deep-sea mining has been coming for the better part of 50 years. Now, experts argue that this process can be done sustainably, with minimal disturbance to the surrounding seafloor. (Undark)

Use our resources to better understand undersea mining—and the other kind of SMS.

Teachers, scroll down for a short list of key resources in our Teachers’ Toolkit, including today’s simple MapMaker Interactive map.

An ocean vent sits over a deep fissure in the ocean floor. Ocean vents eject hot, often toxic, fluids and gases into the surrounding seawater. They often mark sites of tectonic activity, and create some of the most hostile habitats on Earth. There are many different types of ocean vents: diffuse flows, black smokers, white smokers, and vents associated with undersea volcanoes. Scroll through this gallery to peek into some vents, and click here for a history of their discovery.

Diffuse flows can often lack the telltale color of hydrothermal vents. This ocean vent in the Sea of Cortez, Mexico, is only visible as a translucent plume. Photograph by Brian J. Skerry, National Geographic

Black smokers, like this one along the mid-Atlantic Ridge, are the largest type of ocean vent, and eject the hottest fluids. Vent fluids heated to more than 400° Celsius (752° Fahrenheit) spew out of tall chimneys at rates of up to 5 meters per second (16 feet per second). Their thick black “smoke” is made of tiny particles of metals (including iron and copper) and salts (mostly sulfates). Photograph by Stephen Low Distribution Inc.

White smokers, like the so-called Champagne vents off the Caribbean island of Dominica, are cooler and more acidic than black smokers. The vent fluids in white smokers lack high metallic content, which gives them their lighter color. Photograph courtesy NOAA

Ocean vents sit over fissures (cracks) in the seafloor. The hot, toxic fluids they emit may color the vent fluid as well as surrounding rocks, like those at the base of this ocean vent in the Brimstone vent field, off the coast of Rota, one of the Mariana Islands in the South Pacific. Photograph courtesy Submarine ROF 2006, NOAA Vents Program. (CC BY 2.0)

Ocean vents are often associated with underwater volcanoes like this one erupting in the Pacific Ocean between Fiji, Tonga, and Samoa. Just as steam vents surround terrestrial volcanoes, ocean vents can surround seamounts. Photograph courtesy NOAA and NSF

• According to the Undark article, deep-sea hydrothermal vents are rich sources of minerals including manganese, gold, copper, zinc, silver, nickel, and rare earth elements. What are these ores used for?
  • These metals are used for heavy industry, and are “essential to smartphones, tablets, and other personal electronics.”
  • This Nat Geo magazine article describes rare earth elements as “the secret ingredients of everything.”

• What are seafloor massive sulfide deposits and how did they accumulate around ocean vents? The final section in our encyclopedic entry on ocean vents might help—just scroll down to the short “Mining” section.
  • SMS deposits describe the metallic ores that surround an ocean vent. As superhot, metal-rich vent fluid exits the ground, it contacts cold seawater. The interaction causes the metals to solidify and accumulate on and around the growing vent chimney. SMS deposits can be material left over from collapsed chimneys or chimneys themselves.

• Where can scientists and mining companies find SMS deposits? Use our activity to help find these “deep-sea geysers.”
  • Although the ocean vents of the South Pacific and Indian Oceans are most attractive to mining companies, hydrothermal vents dot all the world’s ocean basins.
  • Many SMS deposits fall within the exclusive economic zone (EEZ) of developing countries, such as Papua New Guinea and Namibia. This eliminates “the potential complications of mining the seabed that lies under international waters.” (Negotiating territory and extraction rights in the Arctic is an example of these complications.)

• Has seafloor mining ever been tried before? Take a look at today’s MapMaker Interactive map for some help.
  • Yes, but not on a large scale or in deep water. According to the good folks at WHOI, “In the 1960s, Marine Diamond Corp. recovered nearly 1 million carats from the coast of Namibia. Today, de Beers obtains a significant portion of its total diamond production from the continental shelf of southern Africa, in water shallower than 300 meters (1,000 feet).”
  • Solwara I, a 1,600-meter-deep (5,250-feet-deep) vent field off the coast of the island of New Ireland, Papua New Guinea, is world’s first major SMS mining operation. It is expected to begin extraction, primarily of copper and gold, by 2017 or 2018. Learn more about Solwara I extraction program here.

• Why are hydrothermal vents an attractive site for mining?
  • Obviously, SMS deposits are rich in valuable ores.
  • Ocean vents are free of the layers of soil and rock that surface miners must excavate. The ore is literally piled up on the seafloor.

• What makes mining SMS deposits so challenging?
  • Seafloor mining is a complicated and expensive procedure. Although the ores are not underground, they are underwater. The work must be conducted remotely, by specialized equipment that can function in extremely cold, salty water, and, perhaps most crucially, under great pressure.

• How might seafloor mining impact the ecology of ocean vent ecosystems?
  • Extractive activity is always invasive: According to our entry, “[t]he environmental impact is enormous. Microbes and animals are destroyed or displaced as the seafloor is disrupted.”
  • We don’t know what’s out there: According to WHOI, “No two vents discharge exactly the same mixes of fluids, so no two vents are colonized by exactly the same life forms . . . These strange life forms may hold clues to how life started on Earth. So little is known about them that if vents are mined, we may never know what species have been lost.”
  • Extractive activity might impact life beyond the immediate area: Undark reminds us that “[s]urrounding every hydrothermal vent is a halo of fauna that, though not endemic to hydrothermal vents, aggregate around them due to the prodigious amount of food available . . . Halo fauna are deep-sea generalists, adapted to an environment that is vast and stable. Where hydrothermal vent communities may be resilient to the environmental insult of deep-sea mining, any level of disturbance will likely exceed the resilience of the halo community.”

• Why might these ecological concerns not be as serious as they first appear? Both
  • Undark and WHOI provide some mitigating evidence.
    • Catastrophe is the norm: “Deep-sea hydrothermal vents. . . are exceptionally dynamic ecosystems, experiencing natural, occasionally catastrophic disturbance on a decadal time scale. Whether a mining event exceeds the natural disturbance of a hydrothermal vent ecosystem is one of many unknowns of this largely unexplored venture.”
    • Conservation science is ahead of industry: “We have almost 40 years of data about deep-sea hydrothermal vents. This presents us with a rare opportunity to establish environmental and biodiversity baselines at the prospective site and within connected communities, before the first mining tool crawls across the seafloor.”
    • Vents aren’t always isolated: Many SMS-rich vent fields are not isolated ecosystems, but part of a “biogeographic province—an area in which vent systems share the same fauna . . . Identifying and establishing refuges, or vent fields where mining cannot occur, may be adequate to preserve the overall biodiversity of the biogeographic province and act as a source for later recruits if the mine site recovers. In the rare circumstances where we’ve been fortunate enough to observe a vent system recover after volcanic eruptions decimate the community, this has been the case.”
    • These are hardy ecosystems: “The mining industry maintains that it is using and developing environmentally sensitive techniques, and many ocean habitats often appear to recover from damage.”

TEACHERS’ TOOLKIT

Undark: Living With Deep-Sea Mining

Nat Geo: What are ocean vents?

Nat Geo: Where is the world’s first deep-sea mining operation? MapMaker Interactive map

Nat Geo: Deep-Sea Geysers

Woods Hole Oceanographic Institution: What is Seafloor Mining?

Nautilus Minerals: Solwara I