The Rewards and Perils of Mining the Ocean Floor

As far back as I can remember, I loved the ocean. I grew up in Brooklyn and spent as much time as I could swimming in salt water. As I grew older, I realized that the ocean which bordered my hometown was not the best location in which to scuba dive. The water was murky and often polluted with untreated sewage.

Fortunately, my aunt and uncle owned a beach house on Reynolds Channel, a strait in Nassau County, New York. One summer morning I visited them, put on my scuba gear, and for the first time waded into the water below their dock. Until that moment, every body of water I had dived in had gradually deepened the further I got from the shore. Reynolds Channel was different.

As I swam out about 50 yards, I found myself on the edge of an immense underwater canyon. Gazing into the darkness below, I suddenly became distressed. My mind was shouting “What’s down there? Is it dangerous?”

How Our Planet Developed Oceans

The oceans contain 97% of the water on our planet; about 332,000,000 cubic miles. Where did all this water come from?

Hydrogen and oxygen are among the most abundant elements in the universe. Water exists in clouds of empty space, in newborn planetary systems, and in the atmospheres of giant planets in other solar systems.

In our own solar system, Jupiter, Saturn, Uranus and Neptune and their moons and rings contain water ice. Astronomers believe that water exists on Jupiter’s moons Ganymede, Europa and Calisto, and on Saturn’s moon Enceladus and Titan. As these moons orbit their planets, tidal forces stretch and pull the moon’s mass and cause ice to heat up and melt. Consequently, these moons may house liquid oceans below their surfaces.

Around 4.5 billion years ago, the molten Earth began to cool. Over vast periods of time, water vapor and other gases in the atmosphere escaped from molten rock and began to condense. When the planet cooled to below 212 degrees Fahrenheit (the temperature at which water becomes a gas) the water vapor condensed into liquid water (called “juvenile water). It rained for millions of years, filling the hollows and basins to create our oceans. The force of gravity kept the water from escaping into space.

Hydrothermal Vents

Reynolds Channel, where I swam as a boy, was a small-scale version of the enormous trenches and canyons that cut through the ocean floors.

In 1977, scientists discovered vents on the bottom of the Pacific Ocean that pour hot, mineral-rich fluids from the planet’s mantle. Hydrothermal vents form in volcanically active areas — often on mid-ocean ridges, where Earth’s tectonic plates are spreading apart and where magma wells up to the surface or close beneath the seafloor.

Ocean water invades the crust of these vents through cracks and porous rocks and is heated by underlying magma. As the water becomes hotter and more acidic, it leaches metals such as iron, zinc, copper, lead, and cobalt from the surrounding rocks. Temperatures at the vents reach 750 degrees Fahrenheit, yet the water does not boil because of the intense pressure at depths of 4 to 7 miles below sea level.

Because hydrothermal vents act as natural plumbing systems that transport heat and chemicals from the interior of the Earth into the oceans, they help regulate global ocean chemistry. As a result, they cause vast amounts of potentially valuable minerals to accumulate on the seafloor.

Nodules and the ISA

Scientists have recently discovered that the oceans are strewn with potato-sized nodules containing sought-after metals that are scarce on the planet’s surface but abundant on the seafloor. As just one example, scientists estimate that the seafloor houses 6,000 times as much tellurium as exists on the surface. Electric vehicles, wind turbines, batteries and solar panels utilize copper, tellurium, cobalt, nickel and other rare earth elements such as yttrium.

Mining these seabed metals is not only expensive and but may also contribute to the environmental destruction of the previously unknown organisms that thrive around the hypothermal vents.

The strange and beautiful species of fish, crabs, octopuses, worms and countless other species that inhabit these depths seem to have leapt from science fiction novels and movies. Some dangle organic lightbulbs from their heads to illuminate the darkness. Colonies of six-foot long tubeworms live on volcanic vents that spew superheated nutrient-filled water into the ocean.

All of these life forms may now be threatened with extinction.

The Impact of Mining on the Seabed

The International Seabed Authority (ISA) is a watchdog organization housed in Jamaica. The ISA has jurisdiction over how nations can mine the seabed. It gives mining companies permission to develop (or exploit) the seabed within two hundred miles from the land. The ISA controls seabed mining only in the 100,000,000 square miles of seafloor outside this region, which it calls the “Area.” It considers the Area, from the ocean’s surface to the sea, to be “the common heritage of mankind.”

To date, thirty mining companies have applied for and received permits from the International Seabed Authority to mine the seabed. This activity will impact and likely destroy many of the thousands of hitherto unknown species that inhabit the Area.

We need these resources. But we must also value and respect the strange life forms that co-exist with them. Unfortunately, we have a poor track record of preserving species standing in the way of progress.

Will this time be different?