The cameras have left, but tears continue to fall in the Gulf of Mexico, four years after the environmental catastrophe caused by an explosion on British oil giant BP's Deepwater Horizon rig.

In "The Great Invisible", a documentary which won the Grand Jury prize at the South by Southwest (SXSW) festival in Texas, director Margaret Brown shines the spotlight back on the main victims of the disaster.

Australian scientists Wednesday said they had successfully tested a vaccine against chlamydia in wild koalas, in what they believe is a breakthrough in combating the disease ravaging the native marsupial.

The much-loved furry animal has been under increasing threat, with the government classifying it as a vulnerable species amid a plunge in population numbers from habitat loss, disease and other factors.

An unmanned rocket owned by Orbital Sciences Corporation exploded Tuesday in a giant fireball and plummeted back to Earth just seconds after launch on what was to be a resupply mission to the International Space Station.

"The Antares rocket suffered an accident shortly after lift-off," NASA mission control in Houston said, describing the blast at Wallops Island, Virginia, as a "catastrophic anomaly."

A portion of a Columbian mammoth skull and tusks have been uncovered in Idaho, and experts say a rare entire skeleton might be buried there.

Experts estimate the mammoth was about 16 years old and lived about 70,000 to 120,000 years ago in what was a savanna-like country populated with large plant-eaters and predators.

The divers descended 410 feet (125 meters) into dark Mediterranean waters off Italy, their lights revealing the skeleton of a ship that sank thousands of years ago when Rome was a world power. A sea-crusted anchor rested on a rock. The ship's cargo lay scattered amid piles of terra cotta jars, called amphora.

Highly trained technical divers with a Florida-based group called Global Underwater Explorers — GUE for short — are helping Italian researchers to unlock an ancient shipwreck thought to date to the second Punic Wars between Rome and Carthage. Able to descend hundreds of feet (meters) further than most divers, they aide the archaeologists by swimming about the wreck fetching artifacts — as no robotic submersible can.

Space launch operator Arianespace said on Monday that Europe had decided against hoisting two more Galileo geolocation satellites in December following a launch mishap in August.

Two Galileo satellites, part of an orbiting constellation scheduled to completed by 2020, were to have been launched from Kourou, French Guiana, by a Russian Soyuz rocket.

Orbital Sciences postponed its planned launch of the Cygnus cargo ship toward the International Space Station on Monday due to a boat in the waters near the Virginia launch pad.

"Tonight's launch of the Antares rocket carrying the Cygnus cargo craft has been scrubbed," a NASA commentator said on the U.S. space agency's live broadcast.

Australian government plans to protect the Great Barrier Reef are inadequate, short-sighted and will not prevent its decline, the country's pre-eminent grouping of natural scientists said Tuesday.

The draft plan, released for consultation last month, was supposed to allay concerns by the United Nations about the reef's health after UNESCO threatened to put it on the World Heritage "in danger" list.

Japan's coastguard said it arrested a Chinese fishing boat captain Monday on suspicion of coral poaching after a high seas chase in the country's exclusive economic zone.

The boat, the Zheling Yuyun 622, fled after ignoring an order by a Japanese patrol ship to land off one of the Ogasawara islands, some 1,000 kilometers (630 miles) south of Tokyo, according to Japan's coastguard.

China is to build its own airfield in Antarctica, media reported Monday, as Beijing continues to expand its footprint in the most remote corners of the globe.

The airstrip will be built to assist China's four research stations on the frozen continent, the Beijing Evening News said, without giving details such as runway length or capacity.