Oceanography

The origin and movement of waves reaching up to 11 metres that devastated France's Reunion Island in the Indian Ocean on Saturday evening have been detected with ESA's Envisat satellite.

The waves that thrashed the southern port of Saint Pierre, leaving two fishermen missing, causing several piers to collapse and flooding several homes and businesses, originated south of Cape Town, South Africa, and travelled northeast for nearly 4000 km over a period of three days before slamming into Reunion Island.

Threatened coral reefs could be given a helping hand by establishing marine reserves, according to a research team led by the University of Exeter. Marine reserves have already proved to be a successful way of protecting marine life against commercial fishing. Marine reserves could also help in the recovery of corals, which are already suffering the effects of climate change and over-fishing.


Adult male of the queen parrotfish, Scarus vetula, one of the most important grazers on Caribbean coral reefs. Credit: Photograph courtesy of Evan D’Alessandro.

A study released today provides some of the first solid evidence that warming-induced changes in ocean circulation at the end of the last Ice Age caused vast quantities of ancient carbon dioxide to belch from the deep sea into the atmosphere. Scientists believe the carbon dioxide (CO2) releases helped propel the world into further warming. The study, done by researchers at the University of Colorado, Kent State University and Columbia University's Lamont-Doherty Earth Observatory, appears in the May 10 advance online version of the leading journal Science.

Scientists have discovered how ocean circulation is working in the current that flows around Antarctica by tracing the path of helium from underwater volcanoes. The details are published in Nature this week.

The team, led by Alberto Naveira Garabato of the National Oceanography Centre, Southampton (formerly based at the University of East Anglia), has discovered a 'short-circuit' in the circulation of the world's oceans that could aid predictions about future climate change.

Arctic sea ice is melting at a significantly faster rate than projected by even the most advanced computer models, a new study concludes. The research, by scientists at the National Center for Atmospheric Research (NCAR) and the University of Colorado's National Snow and Ice Data Center (NSIDC), shows that the Arctic's ice cover is retreating more rapidly than estimated by any of the 18 computer models used by the Intergovernmental Panel on Climate Change (IPCC) in preparing its 2007 assessments.


This figure illustrates the extent to which Arctic sea ice is melting faster than projected by computer models.

A major study has shed new light on the dim layer of the ocean called the "twilight zone"—where mysterious processes affect the ocean's ability to absorb and store carbon dioxide accumulating in our atmosphere.

The results of two international research expeditions show that carbon dioxide — taken up by photosynthesizing marine plants in the sunlit ocean surface layer — does not necessarily sink to the depths, where it is stored and prevented from re-entering the atmosphere as a greenhouse gas. Instead, carbon transported to the depths on sinking marine particles is often consumed by animals and bacteria and recycled in the twilight zone—100 to 1,000 meters below the surface—and never reaches the deep ocean.

As the national repository for geological material from the Southern Ocean, the Antarctic Marine Geology Research Facility at Florida State University houses the premier collection of Antarctic sediment cores -- and a hot new acquisition will offer an international team of scientists meeting there May 1-4 its best look yet at the impact of global warming on oceans worldwide.

The remarkable new core was extracted during the recent Antarctic summer from record-setting drilling depths 4,214 feet below the sea floor beneath Antarctica's Ross Ice Shelf, the Earth's largest floating ice body. Laced with sediment dating from the present day to about 10 million years ago, the core provides a geologic record of the ice shelf's history in unprecedented detail.

A new "black smoker" -- an undersea mineral chimney emitting hot, iron-darkened water that attracts unusual marine life -- has been discovered at about 8,500 feet underwater by an expedition currently exploring a section of volcanic ridge along the Pacific Ocean floor off Costa Rica.

Expedition leaders have named their discovery the Medusa hydrothermal vent field. The researchers are working aboard WHOI's research vessel Atlantis, and the expedition is funded by the National Science Foundation.

Scientists have found one of the largest fields of seafloor vents gushing super-hot, mineral-rich fluids on a mid-ocean ridge that, until now, remained elusive to the ten-year hunt to find them.

"The discovery of the first active vents ever found on an ultraslow-spreading ridge is a significant milestone event," said Jian Lin, leader of a team of Woods Hole Oceanographic Institution (WHOI) scientists who participated in a Chinese expedition to the remote Southwest Indian Ridge in the Indian Ocean in February and March.

In 2008, scientists will, for the very first time, create a continual profile of ice thickness in the Artic, extending from the Canadian coast across the North Pole to Siberia. At the core of the project lies the crossing of the North Pole by zeppelin. The airship will be equipped with an electromagnetic sensor developed at the Alfred Wegener Institute for Polar and Marine Research. The project of French physician Jean-Louis Etienne is financed by the French oil company Total and will be presented in Berlin on April 5.


Photo composition of the airship "Dirigeable," carrying the EM-Bird. The zeppelin is currently built in Moscow. Credit: Total