German researchers on Wednesday said they had evidence that sowing the ocean with iron particles sucks up and stores carbon dioxide (CO2), preventing the gas from stoking dangerous climate change.

But their work, touching on a fiercely controversial issue called geo-engineering, came under attack from other scientists and environmentalists.

A second nuclear reactor has begun working in Japan, officials said Thursday, the day after its operator was ordered to examine a possible active tectonic fault directly under the plant.

Kansai Electric Power Co. (KEPCO), which runs the Oi power plant in the nation's industrial heartland, said it switched on Unit No. 4 late Wednesday, following the restart of Unit No. 3 reactor earlier this month.

The science world has added an unusual tribute to the long list of accolades bestowed on Nelson Mandela, naming a prehistoric woodpecker after South Africa's first black president, who turns 94 Wednesday.

The anti-apartheid icon has already seen his name conferred on a species of spider, a nuclear particle, an American rescue dog, a tree, several sub-groups of flower, numerous race horses and a flat in a television sitcom.

An iceberg twice the size of Manhattan tore off one of Greenland's largest glaciers, illustrating another dramatic change to the warming island.

For several years, scientists had been watching a long crack near the tip of the northerly Petermann Glacier. On Monday, NASA satellites showed it had broken completely, freeing an iceberg measuring 46 square miles.

U.N. culture and science body UNESCO on Tuesday awarded a prize financed by the leader of Equatorial Guinea despite fierce criticism from rights groups who decried the move as "shameful".

Rights groups and Western nations have condemned the life sciences award, financed to the tune of $3 million (2.5 million euros) over five years, because of accusations that President Teodoro Obiang Nguema rules with an iron grip and heads a government festering with corruption.

Through a labyrinth of hallways deep inside a 1950s-era building that has housed research that dates back to the origins of U.S. space travel, a group of scientists in white coats is stirring, mixing, measuring, brushing and, most important, tasting the end result of their cooking.

Their mission: Build a menu for a planned journey to Mars in the 2030s.

A new biodiesel plant in Cuba -- the first of its type -- is turning seeds from the so-called "bellyache bush" into a green energy source, it was announced Monday.

Jatropha seeds are rich in oil but toxic for human consumption, explained Jose Sotolongo, director of the province's Center for Applied Technology for Sustainable Development.

NASA's Curiosity rover is on target to arrive on Mars on August 6 for a two-year mission to find out whether microbial life once existed on the Red Planet, the U.S. space agency said Monday.

Landing the car-sized rover is of course no easy task, NASA scientists say.

Caterpillars belonging to a species of butterfly previously unknown as far north as Canada have been discovered in Montreal, in a sign that this country's cool climate is warming, researchers said Monday.

The city's botanical garden and insectarium said the giant swallowtail butterflies (Papilio cresphontes Cramer) were recently found for the first time on a prickly ash plant there.

Tens of thousands of people rallied at a Tokyo park Monday demanding that Japan abandon nuclear power as the country prepares to restart another reactor shut down after last year's tsunami-generated meltdown at the Fukushima power plant.

Led by Nobel-winning novelist Kenzaburo Oe, pop star Ryuichi Sakamoto and visual artist Yoshitomo Nara, the protesters expressed outrage over a report that blamed the Fukushima disaster on Japan's culture of "reflexive obedience" and held no individuals responsible.