The Juan de Fuca tectonic plate is by far one of the Earth's smallest. It spans just a few hundred kilometers of the Oregon, Washington, and British Columbia coast. But what the Juan de Fuca lacks in size it makes up for in connectivity. It's home to a unique, high-speed optical cabling that has snaked its way across the depths of the Pacific seafloor plate since late 2009.

This link is called NEPTUNE—the North-East Pacific Time-Series Underwater Networked Experiment—and, at more than 800 kilometers (about 500 miles), it's about the same length as 40,000 subway cars connected in a single, long train.

A team of scientists, researchers, and engineers from the not-for-profit group Oceans Network Canada maintains the network, which cost CAD $111 million to install and $17 million each year to maintain. But know that this isn’t your typical undersea cable. For one, NEPTUNE doesn’t traverse the ocean’s expanse, but instead loops back to its starting point at shore. And though NEPTUNE is designed to facilitate the flow of information through the ocean, it also collects information about the ocean, ocean life, and the ocean floor.

So forget the Internet of Things—NEPTUNE has created an Internet-connected tectonic plate.

Deep sea—the final frontier

University of Washington Oceanography Professor John Delaney first proposed the idea for NEPTUNE in the mid-1990s, sensing the Internet’s then-rapid proliferation would have larger implications than simply connecting home and office PCs. He suggested "distributed robot-sensor networks throughout the oceanic environment" would soon observe the seas continuously in ways that researchers on boats with precious little sea time could scarcely imagine or afford.

Fast-forward to the present day, and constant connectivity to the seafloor is still no small feat. Though we've long since mastered the ability to wirelessly communicate with satellites and spacecraft, some now billions of kilometers away, the depths of the ocean are a different, still nascent frontier. There’s no wireless communication in the water, for starters. Everything must be wired, watertight, and shielded from hazards such as wayward anchors, corrosion, and leaks. In this regard, the Juan de Fuca, too, is a formidable threat; about 400 earthquakes occur across the plate each year.

Incredibly, Ocean Networks Canada has managed to make it all work. Five deep-sea sites along NEPTUNE’s length play host to myriad sensors and instruments, from tsunami detection systems for seismic studies, to measurements of greenhouse gases in ocean ecosystems. The deepest site—a sixth that lacks funding for sustained observation, on the edge of the Juan de Fuca plate—sits 2.4 kilometers (1.5 miles) beneath the surface of the ocean, about as deep as the Alcatel-Lucent submarines that laid NEPTUNE's cabling can dive.

Each site is already providing valuable data, down to the second, on the health of our oceans and the planet overall, in ways that scientists at sea for a few weeks each summer could once only dream. And by connecting this network to the Internet, that data is available for anyone to watch, stream, access, and analyze in real time, worldwide. It's the ultimate realization of Delaney’s vision and one of NEPTUNE’s most important goals.

But bringing NEPTUNE online and keeping it that way hasn’t been easy. Based on its few years of operation, it's safe to say that we never designed computer networks to be operated at such depths.

The setup

Wally is about the size of a mini fridge and roams the Pacific Ocean floor. His tether gives him about 70 meters to move in any given direction, a benthic area of geothermal vents his handlers have affectionately termed "Wallyland." The name has a distinctly amusement-park vibe, if your idea of amusement is a hotbed of bacteria and gas hydrates—the latter, solid blocks of ice-like methane only stable a half mile below the ocean’s surface. This is where Wally has lived for almost two years.

Wally is unusual for robotic undersea crawlers; they don't typically stay underwater for quite this long. Even the scientists who operate him do so in a most unusual way—via remote control, over the Internet, from the other side of the world. Because of NEPTUNE, the crawler is constantly connected, powered from shore, and available 24/7/365.

Geophysicist Martin Scherwath, who acts as something of a liaison between Wally and his faraway German operators, doesn't know of any other deep-sea crawlers that have been installed in this way. But that’s probably because companies such as Alcatel-Lucent don’t typically install things in the sorts of environments that Wally and NEPTUNE’s other instruments call home.

"We wanted to put cables in places they would never go, that they would avoid," Kim Juniper recalls. The marine microbiologist is director of science and user engagement at Ocean Networks Canada, and he acts as a liaison between the cabled network and the scientists worldwide who have developed instruments such as Wally for his team to deploy. From 2004-2006, he served as co-chief scientist, working closely with Alcatel-Lucent on planning NEPTUNE's cabled route.