In a sense, it will be as if dozens of spots on the sea floor had Ethernet ports and power outlets. Into these, scientists will literally be able to plug in almost any kind of instrument they can think of: seismometers, water current meters, nutrient monitors, tethered robotic subs, sea floor rovers, high-definition cameras, and more. "We are providing a whole new dimension to oceanography by bringing power and the Internet to an environment that simply hasn't had that," says Christopher Barnes, the distinguished oceanographer and paleobiologist who is executive director for NEPTUNE Canada. This consortium, based at the University of Victoria, is leading the effort to build the northern third of NEPTUNE.

NEPTUNE will cover one of Earth's most diverse and dynamic landscapes [see map, "NEPTUNE's Realm"]. The network will trace the outline of the Juan de Fuca tectonic plate. One of the smallest of Earth's several dozen tectonic plates, it is bounded by the coast of Oregon, Washington, and British Columbia to the east and the gigantic Pacific tectonic plate a few hundred kilometers out to sea to the west. The plates consist of crusts of rock, tens of kilometers thick, that float atop Earth's mantle layer. Collisions among the crusts produce a lot of important geological phenomena, such as earthquakes and tsunamis.

North America is sliding over Juan de Fuca's eastern edge at the geologically breakneck pace of 4.5 centimeters per year and, in the process, fueling dramatic changes underwater. As the North American plate plows sediments along the ocean bottom, liquids and gases ooze from the seabed, including natural gas hydrates—a frozen mixture of methane and water. The hydrates could prove to be the last frontier for fossil fuel exploration, or they could be a potent source of greenhouse gases whose release could induce sudden climate change.

On Juan de Fuca's southwest edge, about 400 kilometers west of Portland, Ore., rises an undersea volcanic crater that has exploded three times in the last 15 years, making it one of the most active sites in the world and a perfect laboratory to study volcanism.

A few hundred kilometers west of Vancouver Island, Juan de Fuca's collision with the vast Pacific plate gives rise to Endeavor Ridge, a hyperactive earthquake zone whose magma chambers produce 300 ºC jets of water that feed an undersea jungle teaming with bizarre flora and fauna [see photo, "Black Smokers"]. These hydrothermal vents—one of the most important biological discoveries of the past 30 years—have shattered long-held conceptions of life's limits on this planet and the prospects for finding it elsewhere.

Seawater seeping through cracks in the strained sea floor at Endeavor hits magma-heated rock and erupts to the surface as a superhot soup carrying a corrosive mix of dissolved minerals. When the minerals meet the icy water of the ocean bottom, they precipitate out, depositing rock chimneys tens of meters high. Ancient vents like Endeavor's are a likely source of many large ore deposits on land.

But just as important as the geology and geophysics behind the vents is the life they sustain. Before the vents were discovered, biological dogma held that all life was ultimately dependent on the sun for energy. Yet hydrothermal vents such as Endeavor's, which lie in the darkest depths of the sea, support a riot of life. These weird ecosystems—thick mats of microbes, snails, tube worms, giant spider crabs, and stranger stuff—live off the vents' hot chemical plumes. Endeavor is home to at least a dozen species found nowhere else on Earth, including a microbe that thrives at 121 ºC, making it the planet's heat-tolerance champion.

Ecosystems like Endeavor's give hope that life may find a way in seemingly inhospitable extraterrestrial environments, such as Jupiter's icy moon Europa. But exploring Endeavor's hot vents and Juan de Fuca's other treasures has been a slow and often frustrating process. There is never enough time below with submersibles. And getting positioned to observe the plate at its most dynamic moments is a game of hit or miss with today's ship-based oceanography.

Consider the swarm of earthquakes that rattled Endeavor early this year. U.S. Navy hydrophones detected 3742 earthquakes over a six-day period, a sign that the plate's crust was stretching. It was an excellent opportunity to measure how fast the crust is moving—a key parameter needed to predict the Pacific Northwest's next killer earthquake. Scrambling a research ship, Seattle-based University of Washington seismologists set out to deploy more-sensitive instruments. But they arrived one week after the swarm began—and one day after it ended.

Such frustrations inspired the pioneers behind NEPTUNE. In the early 1990s, John Delaney, a professor of oceanography at the University of Washington, began to work on the idea of making a cabled observatory at Endeavor Ridge that would provide continuous power and telecommunications to instruments there. He found an enthusiastic ally in University of Victoria biologist Verena J. Tunnicliffe, who made some of the earliest discoveries about the vents' ecology and who was equally frustrated by the piecemeal science she was restricted to on a ship.

By 2000, Delaney and Tunnicliffe had assembled a steering committee from five institutions to try to make NEPTUNE a reality. It included their home institutions as well as the Monterey Bay Aquarium Research Institute; the Woods Hole Oceanographic Institution, which brought experience in developing underwater research technology; and the NASA Jet Propulsion Laboratory. JPL, in Pasadena, Calif., contributed its expertise in engineering for long-term operation in the most remote environment of all: space.

Together, researchers at these institutions have forged a plan for 3000 km of power and fiber-optic cable emanating from shore stations on Vancouver Island and the Oregon coast and linking some 30 science stations, or nodes [see again, "NEPTUNE's Realm"]. Data and power lines radiate from the nodes to dozens of sensors. This integrated network of instruments should be capable of monitoring every shake and shudder of the tectonic plate, each puff from volcanic vents, and the shifting circulation of the sea above without an oceanographer donning so much as a sweater, let alone a wet suit.

With NEPTUNE, oceanographers are aiming for an observatory infrastructure that is robust enough to last 30 years and versatile enough to provide power to, and stream data from, essentially any kind of instrument an ocean scientist might need. Scientists will help design instruments to be installed on NEPTUNE nodes and may get some brief exclusive use, but in short order the instruments—and their data streams—will become available to their peers and perhaps even to the public. Doing science with NEPTUNE will be more like mining a fast-growing database than signing up for a few days aboard Alvin.