In many ways, undersea rivers are similar to the rivers we see on land. They have banks on either side. Smaller rivers called “tributaries” feed into larger ones. The rivers carve valleys into the sea floor. They follow meandering paths and can even change course, resulting in abandoned sections similar to oxbow lakes. Ultimately, they spill out onto the abyssal plain in the ocean depths in similar ways to a river estuary.
Rather than flows of fresh (or at least salty) water, undersea rivers are slurries of silt and sand that cascade along channels on the seabed. Each particle tumbles through the water under its own weight. A new river starts on the continental shelf like an avalanche in the mountains, picking up speed and momentum as it moves until it flows like a liquid. Once started, an undersea river can flow for weeks and even months at a time, moving the same amount of sediment in one go that all the world’s land-based rivers transport in an entire year.
Yet the sheer power of these enormous flows of sediment can make studying them a challenge. In January 2016, Paull and his team lost a fixed monitoring device, along with the one-tonne tripod it was mounted on, when a powerful sediment flow swept down the Monterey Canyon at 12mph (19.3km/h). They eventually found it, after following the pings from its beacon – three miles from its original position, almost completely buried in mud. When they managed to pull it out, they found steel plates on the frame had been bent out of shape and ground down to a knife-edge. A float on top of the tripod, made of carbon fibre and titanium, had also been badly eroded. Ten months later, they lost a second tripod in a similar manner, while another event saw an entire mooring dragged four miles (7.1km) out of position.
With only 5 percent of the ocean floor mapped, our knowledge of what’s beneath is about as detailed as a set dinner table with a wet blanket thrown over it. You can see the outlines, but how do you tell the candelabra from the turkey?
Fortunately, we’re about to whip the blanket off and reveal this aquatic meal in exquisite detail. In June, an international team of oceanographers launched the first effort to create a comprehensive map of all the world’s oceans. To map some 140 million square miles of sea floor, the Seabed 2030 project is currently recruiting around 100 ships that will circumscribe the globe for 13 years. The team, united under the non-profit group General Bathymetric Chart of the Oceans (GEBCO), recently announced it had received $18.5 million dollars from the Nippon Foundation for its efforts.
Modern ships like those that will be employed by Seabed 2030 are outfitted with multibeam bathymetry systems. These sensors ping large swaths of ocean floor with sound waves that bounce back, and are analyzed by computers on deck. One ship can now provide thousands of square kilometers’ worth of high-resolution maps during an expedition. Still, it would take a lone ship approximately 200 years to chart all 139.7 million square miles of ocean.
That’s where Seabed 2030 comes in. It will facilitate the collection of multibeam measurements on a coalition of ships charting previously unexplored territory, while also serving as a repository of existing map data. “When you look at a world map it seems like we’ve got it all figured out,” Jakobsson says. But those maps are just rough, artistic estimations of what the seafloor looks like. “I foresee a lot of new discoveries,” he says of the mapping project. After all, “our major discoveries have been because of mapping”—and there’s a lot more to be found.
Naturally, there are many enterprises waiting to put this knowledge to productive use, though, as always, environmentalists are not too happy:
The discoveries lying in wait beneath the waves aren’t only of interest to oceanographers. Hidden in the subsea mountains and valleys are vast pools of resources like precious metals, rare earth elements and even diamonds. “It’s like the old Klondike [Gold Rush], but the streams lead to the ocean,” says Steven Scott, professor of geology at the University of Toronto and consultant to the marine mining industry. “There’s mining for diamonds off of Southern Africa, tin deposits off of Indonesia, gold off Alaska.”
Currently, seafloor mining only takes place in these relatively shallow, near-shore locations, rather than in deep international waters. That’s partly because prospectors can’t target mining operations without accurate maps of most of the sea floor, but also because international laws make it challenging to exploit resources in international waters.
“We know so little about potential environmental impacts” of ocean mining, Gjerde says. “Some are starting to question if we know enough to authorize mining to proceed. We really need a better understanding of the deep sea before we start to do any irremediable harm.” Gjerde is co-author on a recent editorial in the journal Nature Geoscience arguing that while deep-sea mining might fuel economic development, the industry should increase its efforts to protect marine habitats.
“Mines on land are soon going to run out,” Scott says. “Every electronic device in the world has rare earth [metals] in it … we need raw resources.” And what happens when we eventually run out of things to mine from the ocean? Scott says, “We start mining asteroids, or Mars.” Well, at least we’ve already got the maps for those.
1200 workers convert an above ground train line to a subway line in 4 hours. Because the workers had such a tight time to complete the project, every step had to be tightly choreographed.
Tokyu Railways, the operators of the track, are one of Tokyo’s numerous competing private rail companies.
On a more pessimistic note: tech venture capitalists sink 10 million dollars into a “wireless ultrasound phone charger”. If built, this would no doubt be incredibly useful — the only wrinkle is that the very concept defies the laws of physics:
Having done my share of ultrasound physics AND wireless charging work in the past, the first thing that struck me about the idea was that, to transmit any appreciable amount of energy through sound waves, those waves would likely burn you, or at least deafen you, and any other small animals in the vicinity. This is why charging is currently done inside copper wires surrounded by plastic – so you don’t get hurt!
I used nice round numbers and assumed things like perfect focusing and a 1 square meter transmitter (seriously… 3 feet by 3 feet?? The cracks are showing…) and then calculated how much power you’d end up with at the phone, and it turns out to be about 100x less than the standard wall charger. That means it’ll take 100x longer to charge your phone with one of these, assuming you’re willing to deafen your dog and mount a 9 square foot speaker on the wall. Instead of a charge taking overnight, with UBeam it’ll take three months. Oh, and whatever you do, don’t ever stand in front of it or you might get killed!
UBeam’s investors included top tech investors Andreesen Horowitz, and it’s disheartening that they’re willing to throw money at such a project without doing proper due diligence. Though the company’s PR machine is still whirling, last year, their former VP of engineering wrote a series of blog posts confirming the above claims and describing the company as a sham. It’s a fascinating insight into the dark underbelly of technology innovation.