On the ocean floor, at a depth that not even sunlight can reach, volcanoes are spewing precious minerals at temperatures reaching 750 degrees Fahrenheit. These hydrothermal vents somehow also provide the opportunity for life.

The vents release iron, zinc, copper, lead, and cobalt, and a whole host of strange sea creatures call them home. More than 300 species have been identified living in and around hydrothermal vents, according to the World Wildlife Fund, and 95% of them had never been seen before.

But mining companies see these vents as an opportunity to extract resources from the ocean floor. Though no undersea mining has started yet, several companies are getting ready to do so.

A hydrothermal vent on the Ring of Fire erupts more than 1,800 feet under the sea. Submarine ROF 2006, NOAA Vents Program In 2011, the government of Papua New Guinea granted Nautilus Minerals a lease to extract minerals from the hydrothermal vents around its islands. But the company has said its Solwara 1 project to mine copper and gold is still in the exploration phase, and will likely not begin mining until 2018.

Deep-sea mining, as Nautilus Minerals explains it, is similar to how minerals are mined on land. The company plans to use large machines to cut the rock containing minerals on the sea floor, then collect the rock and seawater slurry to pump it to the surface. Once the slurry reaches the ship at the surface, it is strained and the water is pumped back to the seafloor.

Since no hydrothermal vent mining has started yet, some scientists are arguing that now is the time to decide internationally if we want to allow it at all, and if we do — what standards we have for ensuring it has the littlest environmental impact possible.

—Andrew David Thaler (@SFriedScientist) June 9, 2015

Earlier this year, Nautilus commissioned what it said was an independent environmental review from Earth Economics, a non-partisan, non-profit research group. "Solwara 1 appears to be a well-planned, carefully developed project with a clear opportunity to dramatically reduce the social and environmental impacts of copper mining," the report concluded.

A traditional copper mine on land in the eastern region of Papua, Indonesia. Muhammad Adimaja/Antara Foto/REUTERS But a coalition of environmental groups, based in Canada, questioned the report's findings, saying Solwara 1 had far more environmental impacts to consider, like what disrupting the rare ecosystems of hydrothermal vents could do.

"The report compares only the first of several potential Solwara sites with massive industrial scale terrestrial mines," said Catherine Coumans of Mining Watch Canada in a press release, which "is like comparing apples to mangoes."

Luckily, scientists have had 40 years to study the ecosystems of hydrothermal vents since they were discovered in the 1977.

"This gives us the opportunity to think about how to do deep-sea mining right," deep-sea ecologist Andrew David Thaler told Nautilus (the magazine, not the company). "Like any mining process, it's ultimately destructive, but there are ways to do it to minimize the extent of the destruction. ... But until someone goes down and mines, we don't know if they're actually walking the walk rather than talking the talk. So the first deep-sea mines will be an experiment."

A hydrothermal vent erupts on the Ring of Fire, deep undersea.