WILLIAM BRANGHAM: Along certain parts of the ocean floor lie a bounty of rare minerals and metals, critical components for batteries, electric cars and other electronics.

But mining for them in the deep sea is a controversial and potentially destructive process.

Special correspondent Willem Marx detailed the process and the stakes in a series of "News Hour" reports last year.

Marx now has a new piece in "Scientific American" on the controversy.

And he joins us now.

Willem, thanks so much for being here.

Before we get to the debate over this mining practice, tell us a little bit more about what is down there and why there's such a strong incentive to go get it.

WILLEM MARX: Well, there's a variety, William, of deposits all over the planet from various depths in our various oceans.

And those often include very valuable metals, things like copper, cobalt, zinc, lead, what's known as rare earth minerals.

Some of the deposits contain gold and silver.

And so the incentive, as is often the case with mining, is around money.

But, as you mentioned, at the moment in this era where we're transitioning as a species essentially away from fossil fuels to renewable energy, some of these metals, in particular, things like cobalt, like copper, are crucial not just for electric cars, but also for electric power, building infrastructure, grid for our electricity systems.

And so there's a huge incentive for miners, given high prices for some of these metals, to spend money and try and find new deposits.

And one area that has until now really been entirely untapped is at the bottom of the ocean.

WILLIAM BRANGHAM: As you detailed in your stories for the "News Hour," it's quite a process to bring that treasure from the ocean floor up to the surface.

What did you see?

And what else, what other kinds of procedures do mining companies use?

WILLEM MARX: So, a lot of this is really quite experimental at this stage.

It's not been done at huge scales until now.

There's a number of different companies out there who've looked at developing a variety of techniques.

The vessel that we visited in Papua New Guinea last year was trialing a new system that essentially sent a huge 12-ton hydraulically-powered claw a mile down from a surface vessel.

And at the bottom of the ocean, as it hit the seafloor, that claw would dig into the surface and try and pull up anywhere from two to three to as much as six or seven tons of material, and then essentially hoist them a mile back up to the surface with the help, I should add on, on the floor of a remotely operated vehicle, essentially an unmanned submersible, that would guide it into the right position.

And it was a really intricate, complex task.

You had a winch operator on the surface vessel coordinating with the individuals who were piloting this remotely operated vessel a mile down beneath them.

And there was a bit of a dance to try and make sure that the jaws closed around the surface successfully.

Some of the other operators are looking at trying to more or less hoover, vacuum up the material from the floor.

There are different types of deposits, some of which are like small rocks.

And they want to try and hoover those up, vacuum those up along these huge hoses up to surface vessels, clean out the gunk, deposit that gunk back into the ocean.

And that leads, of course, to some of the concerns about the environmental impact as well, as you might imagine.

WILLIAM BRANGHAM: President Trump has reportedly expressed interest in assigning an executive order to speed this process along.

Is there a governing authority that has any jurisdiction over this?

And what might an American president's executive order do to that process and to this industry?

WILLEM MARX: It's really complex.

It's rooted in a treaty that was signed more than four decades ago known as the Law of the Sea, to which the United States is not currently a party.

But to try and break it down as clearly as possible, within 200 miles of every coastal country's shoreline, they are able to exercise what's known as exclusive economic control.

These are exclusive economic zones, particular to each coastal nation.

And within that area, those governments have jurisdiction over essentially what happens in their oceans, whether that's mining or fishing.

Beyond 200 miles, nautical miles, I should add, from a shoreline, you enter what are known as international waters.

And under this treaty the Law of the Sea, those international waters are under the jurisdiction of a U.N.-affiliated body known as the International Seabed Authority.

It's headquartered in Jamaica and the Caribbean.

And that body has been promising for many years now to essentially set up a series of rules that will allow not just the exploration of these international waters, but potentially also the exploitation, that is, mining.

And for many years, they promised regulations.

And for many years, members of this nascent industry, deep-sea mining industry, have been waiting in vain for those new regulations to be issued.

And what President Trump seems to have been suggesting in the last few weeks when he has talked about this publicly, talking about an executive order that would essentially override the International Seabed Authority, to which the United States right now is not a member nation, and say to mining companies, you know what, we as the U.S. authorize you with a mining permit to go out and extract these types of minerals and metals from the deep ocean.

And that would throw this entire industry into an entirely new region in terms of what's possible for investors, what's possible for operators, and, until now, the status quo would be completely undermined.

WILLIAM BRANGHAM: All right, that is "News Hour" special correspondent Willem Marx.

Willem, thank you so much for being here.

WILLEM MARX: Thanks so much, William.