Oceanography

A Duke University-led analysis of available records shows that while the North Atlantic Ocean’s surface waters warmed in the 50 years between 1950 and 2000, the change was not uniform. In fact, the subpolar regions cooled at the same time that subtropical and tropical waters warmed.

This striking pattern can be explained largely by the influence of a natural and cyclical wind circulation pattern called the North Atlantic Oscillation (NAO), wrote authors of a study published Thursday, Jan. 3, in Science Express.

Winds that power the NAO are driven by atmospheric pressure differences between areas around Iceland and the Azores.

New research published in Quaternary Science Reviews says the collapse of the North American (Laurentide) Ice Sheet caused the flood believed to be behind the "Noah's Ark" story 8000 years ago that kick-started modern European agriculture.

The results indicate a catastrophic rise in global sea level led to the flooding of the Black Sea and drove dramatic social change across Europe. The research team argues that, in the face of rising sea levels driven by contemporary climate change, we can learn important lessons from the past.

The collapse of the Laurentide Ice Sheet released a deluge of water that increased global sea levels by up to 1.4 meters and caused the largest North Atlantic freshwater pulse of the last 100,000 years.

Giant waves, also known as monster waves, have been talked about by sailors for centuries, often related to unexplained disappearances at sea, but no one quite believed them.

They have been considered merely a myth until recently, when new studies using technological developments like buoys, radars and satellites have scientifically proven the existence of rogue waves, and that they exist in much higher numbers than it was ever expected.

These rogue waves could be the cause of tragic accidents at sea, not only because of their immense power and heights that reach over 30 meters, but it is their unpredictable nature that poses a bigger threat; they emerge as unexpected mighty walls of water towering from calm seas.

Tiny probes packed with instrumentation have been turned loose in a laboratory in France. The marble-sized devices are an important step on the road to long-anticipated miniaturized machines known as smart dust (picture the artificial swarm in Michael Creighton's "Prey," only without the bloodlust). The small and simple machines are being developed to be released in large numbers to collect data about the motion of fluid systems such as ocean currents and atmospheric winds.

The two centimeter probes are on the large side for smart dust (typically, miniature machines must fill a volume of a cubic centimeter or less to make the cut), still the probes' abilities are impressive for their size.

Australia’s coral reefs, particularly the Great Barrier Reef, are national icons, of great economic, social, and aesthetic value. Tourism on the Great Barrier Reef alone contributes approximately $5 billion annually to the Australia’s economy. Income from recreational and commercial fishing on tropical reefs contributes a further $400 million annually. Consequently, science-based management of coral reefs is a national priority.

Globally, the welfare of 500 million people is closely linked to the goods and services provided by coral reef biodiversity.

The world’s oceans are becoming more acid, with potentially devastating consequences for corals and the marine organisms that build reefs and provide much of the Earth’s breathable oxygen.

In 2007, Arctic summer sea ice reached its lowest extent on record - nearly 25% less than the previous low set in 2005. At the end of each summer, the sea ice cover reaches its minimum extent and what is left is what is called the perennial ice cover which consists mainly of thick multi-year ice floes.

The area of the perennial ice has been steadily decreasing since the satellite record began in 1979, at a rate of about 10% per decade. But the 2007 minimum, reached on September 14, is far below the previous record made in 2005 and is about 38% lower than the climatological average. Such a dramatic loss has implications for ecology, climate and industry as new shipping lanes open.

This visualization shows the annual Arctic sea ice minimum from 1979 to 2007.

A new study says that salt-saturated brine moving through floating sea ice follows “universal transport properties” and that this new understanding can help anticipate the effects of global warming on the polar oceans and the microbial communities existing there.

According to this new model, similar porous materials – including ice on other worlds, such as Jupiter’s icy ocean-covered moon Europa – should follow the same rules.

“It means that almost the exact same formulas describing how water flows through sedimentary rocks in the Earth's crust apply to brine flow in sea ice, even though the microstructural details of the rocks are quite different from sea ice,” says University of Utah math Professor Ken Golden.

Australian scientists have identified the missing deep ocean pathway – or ‘supergyre’ – linking the three Southern Hemisphere ocean basins in research that will help them explain more accurately how the ocean governs global climate.

The new research confirms the current sweeping out of the Tasman Sea past Tasmania and towards the South Atlantic is a previously undetected component of the world climate system’s engine-room – the thermohaline circulation or ‘global conveyor belt’.

Wealth from Oceans Flagship scientist Ken Ridgway says the current, called the Tasman Outflow, occurs at an average depth of 800-1,000 metres and may play an important role in the response of the conveyor belt to climate change.


Oce

More than a mile beneath the Atlantic’s surface, roughly halfway between New York and Portugal, seawater rushing through the narrow gullies of an underwater mountain range much as winds gust between a city’s tall buildings is generating one of the most turbulent areas ever observed in the deep ocean.

In fact, the turbulence packs an energy wallop equal to about five million watts -- comparable to output from a small nuclear reactor, according to a landmark study led by Florida State University researcher Louis St. Laurent.

The study -- an international collaboration of scientists from the United States and France -- documents for the first time the turbulent conditions in an undersea mountain range known as the Mid-Atlantic Ridge.

Finding a decent, honest mate is challenging enough without the added problem of reduced visibility caused by human-induced changes to the aquatic environment.

Yet this is precisely the sort of dilemma female stickleback fish are facing in the Baltic Sea, according to a recent study published in the August issue of the American Naturalist by Dr. Bob Wong, an Australian researcher from Monash University, and his Scandinavian colleagues, Dr. Ulrika Candolin from the University of Uppsala and Dr. Kai Linstrom from the Åbo Akademi in Finland.