National Geographic News reports that sea levels on the US east coast have risen as a result of a slowing gulf stream - Sea Levels Rose Two Feet This Summer in U.S. East.

Sea levels rose as much as 2 feet (60 centimeters) higher than predicted this summer along the U.S. East Coast, surprising scientists who forecast such periodic fluctuations.

The immediate cause of the unexpected rise has now been solved, U.S. officials say in a new report (hint: it wasn't global warming). But the underlying reason remains a mystery.

Usually, predicting seasonal tides and sea levels is a pretty cut-and-dried process, governed by the known movements and gravitational influences of astronomical bodies like the moon, said Rich Edwing, deputy director for the Center for Operational Oceanographic Products and Services at the U.S. National Oceanic and Atmospheric Administration (NOAA).

But NOAA's phones began ringing this summer when East Coast residents reported higher than predicted water levels, much like those associated with short-term weather events like tropical storms. But these high seas persisted for weeks, throughout June and July.

The startling rise caused only minor coastal flooding—but major head scratching among scientists.

Gulf Stream Mysteriously Slowed

Now a new report has identified the two major factors behind the high sea levels—a weakened Gulf Stream and steady winds from the northeastern Atlantic.

The Gulf Stream is a northward-flowing superhighway of ocean water off the U.S. East Coast. Running at full steam, the powerful current pulls water into its "orbit" and away from the East Coast.

But this summer, for reasons unknown, "the Gulf Stream slowed down," Edwing said, sending water toward the coasts—and sea levels shooting upward. ...

Even before the new report, released by NOAA on September 2, Apostolides said many local fishers had already attributed the sea level rise to the "ferocious" winds from the northeast.

But the underlying puzzle remains.

"Why did the Gulf Stream slow down? Why did the fall wind pattern appear earlier?" NOAA's Edwing said. "We don't have those answers."

Scientific American has a slide show on ocean energy from the gulf stream being used to power Florida - Could the Gulf Stream Provide Florida with Renewable Energy?.

Could the Gulf Stream be used as a renewable energy source to supply much-needed electricity to Florida's heavily populated southern region? That's what a team of researchers from Florida Atlantic University (F.A.U.) in Boca Raton are hoping to find out from four acoustic doppler current profilers (ADCP) that they dropped into the Atlantic Ocean between five miles (eight kilometers) and 22 miles (35 kilometers) from the sands of Dania Beach. The ADCPs, which were placed in the water in February at depths between 725 feet (220 meters) and 2,115 feet (645 meters), use high-frequency, low-power sonar to measure the Gulf Stream's water velocity at different locations, according to the school's Center for Ocean Energy Technology (COET).

COET researchers want to determine whether it is feasible to use underwater tidal turbines—like those now being tested in New York City's East River and elsewhere—to generate renewable energy from the powerful Gulf Stream without harming the underwater ecosystem. The scientists plan to gather as much information as possible about the North Atlantic's massive stream over the next eight months, before putting their prototype 20-kilowatt tidal turbine in the water. Their goal, says Howard Hanson, COET's scientific director: to pin down where the current is strongest.

The deployment of the ADCPs is the first step in COET's plans to create a National Open-ocean Energy Laboratory (NOEL) with a permanent infrastructure off the south Florida shore where makers of tidal turbines and other marine-based renewable energy technology would be able to test their devices. NOEL is expected to provide access to federal and state agencies, technology developers, and universities for testing and evaluation of ocean energy systems, from small subscale outfits to full-scale commercial complexes.

"Most companies aren't going to want to put the infrastructure in place to do it themselves," Hanson says. "Our mission is to become a national laboratory for companies to do this."

EE Times has an update on efforts to harness the power of the Gulf Stream - Going deep: Ocean to power grid, recharge fuel cells.

Harnessing ocean power to generate electricity, hydrogen to fuel cars and heat exchangers to cool buildings is the aim of a $13.75 million effort at Florida Atlantic University's Center for Ocean Energy Technology.

The Center has already built a fleet of acoustic doppler current-profiler platforms to be anchored later this year off Florida's Atlantic coast. By 2009, the Center hopes to have permanent mooring sites picked for underwater adaptations of wind turbines. The ocean turbines would be mated to on-shore hydrogen storage facilities that could recharge fuel cells and generate electricity. The moorings will also house pumping facilities to pipe frigid deep ocean water coming from the Arctic Circle into buildings' heat exchangers for cooling.

"The Gulf Stream works 365 days a year, allowing electricity generated from its current to be available 24/7, compared with solar or wind resources. Plus there is a the possibility of using the thermal difference between the warm waters nearer the surface, and the very cold water at the bottom which comes from the Arctic Circle," said Sue Skemp, COET's executive director. ...

The project will also seek to harvest chilly waters at the bottom of the Gulf Stream, similar to a project already underway in Hawaii, Skemp said. Electrical generators in Hawaii currently harness geothermal gradients inside lava tubes. Researchers there also have experience piping cold water ashore from the ocean depths for use in heat exchangers used to cool buildings.

The first Florida project starting later this summer, will establish temporary moorings 13 to 15 miles offshore for acoustic doppler current-profilers used to evaluate how much the Gulf Stream wanders. The fleet of acoustic sensors will evaluate specific sites for energy-generation potential, as well as to catalog the local ecology and evaluate the environmental impact of an underwater power plant.

Renewable Energy World has a post on ocean energy researchers in Florida and their plans to tap into the Gulf Stream current - US Researchers Hope to Tap Ocean Flows for Electricity.

The same energy that drives ocean waves and currents may be a rich source of electrical power. Researchers in Florida say even gentle flows of two or three knots are enough to drive a propeller attached to an underwater turbine. Advocates say ocean power could be cheap and help replace oil or coal-based systems that are blamed for global warming.

Douglas Bedgood is president of Keys Hydro Power and says he wants to build a turbine farm in the Florida Keys, "We could upscale this to 10 feet [three meters] across and it would be perfect."

The goal is to harness the energy produced by the rise and fall of waters during the tidal cycle. His group is working on a test turbine that it plans to submerge in a site about nine meters under water between two islands. "By the end of 2008 or early 2009, we will have several [turbines] just to see how we can manage them as a group. Then another year after, it will be several hundred," Bedgood said. ...

Similar projects are planned in Europe and other U.S. cities. Just 300 kilometers from Key West, researchers at Florida Atlantic University want to tap the powerful Gulf Stream current that brings warm water north into the Atlantic Ocean.

"So it is a significant velocity with the equivalent energy of some of the world's richest energy sites," says Rick Driscoll, who is head of the university's Center for Ocean Energy Technology.