SCUBA Travel News

Sensors developed by the University of St Andrews have been employed by Antarctic researchers to collect otherwise inaccessible information about the climate. The small data logging transmitters have been attached to the heads of elephant seals.

Scientists usually collect data to characterise the ocean using satellite sensing, buoyant floats, and ship expeditions, but winter sea ice renders the Southern Ocean virtually impermeable to all three.

Professor Mike Fedak from the University's Gatty Marine Laboratory said, "The Southern Ocean is a hotspot for climate research because its circulation is critical to understanding the earths climate and its huge ice sheet is sensitive to climate change.

"Southern elephant seals are wide-ranging predators that roam all over the Southern Ocean, even under the sea ice in the wintertime - a time when conventional ocean observation methods are unable to gather data."

The instruments measure temperature, pressure, and salinity and transmit data as well as seal positions to satellites when the seals surface. From this, researchers are able to amass data for a vast range of hitherto inaccessible ocean, including areas deep within the sea-ice in winter while also learning about the animals themselves.

This new data has enabled them to follow the yearly rise-and-fall cycle of sea ice production, and should help scientists refine computer models of the Southern Ocean circulation.

Led by Dr Jean-Benoit Charrassin, a marine biologist at the Natural History Museum in Paris, researchers in France, the UK, Australia and the US have attached electronic dataloggers to 70 seals at the four most important breeding colonies of southern elephant seals.

The species can dive as deep as 2 km in search of food while ranging across much of the southern ocean. Thanks to this innovative technology, the only remaining area with limited coverage is the Pacific sector, which contains no islands for the seals to breed on.

Professor Fedak explained, "I think this is an extremely exciting new approach for ocean observation which has now been extended to seals roaming the seas around both Poles as part of the International Polar Year (IPY)."

The on-going MEOP project (Marine Mammals Exploring the Oceans Pole to Pole) has equipped 100 seals of 3 polar species with oceanographic sensors and these animals are now routinely sending large quantities of near real-time information from the undersampled polar regions.

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Labels: environment, research

Some large whale species, including the humpback, are now less threatened with extinction, according to the cetacean update of the 2008 IUCN Red List. Most small coastal and freshwater cetaceans, however, are moving closer to extinction.

The humpback whale (Megaptera novaeangliae) has moved from Vulnerable to Least Concern, meaning it is at low risk of extinction, although two subpopulations are Endangered. The southern right whale (Eubalaena australis) has also moved to Least Concern.

“Humpbacks and southern right whales are making a comeback in much of their range mainly because they have been protected from commercial hunting,” says Randall Reeves, Chair of the Cetacean Specialist Group of the IUCN Species Survival Commission, who led the IUCN Red List assessment. “This is a great conservation success and clearly shows what needs to be done to ensure these ocean giants survive.”

Despite the improvement in status of these two species, the assessment revealed deterioration in the status of others. Overall, nearly a quarter of cetacean species are considered threatened, and of those, more than 10% (nine species) are listed as Endangered or Critically Endangered, the highest categories of threat. In addition, two subspecies and 12 subpopulations are listed as Critically Endangered.

Whales are under threat in many areas from ship strikes, entanglement in fishing gear, habitat deterioration, declining prey and noise disturbance.

Military sonar is another threat that particularly affects deep-diving beaked whales and other cetaceans like the melon-headed whale. Mass strandings of these species have occurred more often in the last 30 years.

“Large parts of the oceans are now filled with human-generated noise, not only from military sonar but also from seismic surveys and shipping. This noise undoubtedly affects many cetaceans, in some cases leading to their death,” says Jan Schipper, Conservation International and IUCN Global Mammal Assessment Director. “It may not always kill whales and dolphins, but it affects their ability to communicate and it can drive them away, at least temporarily, from their feeding grounds.”

Climate change is also starting to affect whales. The distribution of many species is changing, with the potential for a cascade of effects such as exposure to new diseases, inter-species competition and changes in prey populations. The Antarctic great whales, for example, depend on krill for food. As water temperatures rise, krill populations may decline, leaving such whales short of food.

“To save whales for future generations, we need to work closely with the fishing industry, the military and offshore enterprises including shippers and oil developers – and we need to fight climate change,” says Julia Marton-Lefèvre, IUCN Director General.

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Labels: environment, SCUBA News, whale and dolphins

The first scientific mission with Sentry, a newly developed robot capable of diving as deep as 5,000 meters (3.1 miles) into the ocean, has been successfully completed by scientists and engineers from the Woods Hole Oceanographic Institution (WHOI) and the University of Washington (UW).

The vehicle surveyed and helped pinpoint several proposed deep-water sites for seafloor instruments that will be deployed in the National Science Foundation (NSF)'s planned Ocean Observatories Initiative (OOI).

Sentry is a state-of-the-art, free-swimming underwater robot that can operate independently, without tethers or other connections to a research ship.

The autonomous underwater vehicle, or AUV, is pre-programmed with guidance for deep-water surveying, but it can also make its own decisions about navigation on the terrain of the seafloor.

"This investment into emerging technologies is paying off in delivering state-of-the-art science support," said Julie Morris, director of NSF's Division of Ocean Sciences. "In the near future, Sentry will conduct high-resolution oceanographic surveys that would be otherwise impossible."

Working in tandem with sonar instruments on the UW-operated research vessel Thomas G. Thompson and with photo-mapping by WHOI's TowCam seafloor imaging system, Sentry gathered the most precise maps to date of seafloor features known as Hydrate Ridge and Axial Volcano off the coast of Oregon and Washington.

The AUV can collect the data needed to make seafloor maps at a resolution of less than one meter. On this first cruise, Sentry collected as many as 60 million individual soundings of seafloor depth in a single dive.

Powered by more than 1,000 lithium-ion batteries-similar to those used in laptop computers, though adapted for extreme pressures, Sentry dove for as long as 18 hours and 58 kilometers, with the potential for longer trips in the future.

Sentry is designed to swim like a fish or fly like a helicopter through the water. The sleek hydrodynamic design allows the vehicle to descend quickly from the sea surface to the depths (about 3,500 meters per hour). The novel shape also gives the vehicle tremendous stability and balance while cruising through bottom currents.

The vehicle has thrusters built into its foils, or wings. Like an airplane, the foils allow the vehicle to gain lift or drag or directional momentum, as needed.

When necessary, the AUV also can hover over the bottom for close-up inspections, navigational decision-making, and for rising up and down over rugged seafloor terrain. The design allows the vehicle to start, stop, and change directions, whereas many AUVs tend to travel in one direction.

The AUV steers itself with a magnetic compass; long-baseline (LBL) navigation triangulated from underwater beacons; a sophisticated inertial guidance system (INS); and, when within 200 meters of the bottom, an acoustic sensor that can track the vehicles' direction and speed with incredible precision.

"Sentry is a true robot, functioning on its own in the deep water," said Rod Catanach, a WHOI engineer who works with Sentry. "The vehicle is completely on its own from the time it is unplugged on the deck and cut loose in the water."

Eventually, vehicles like Sentry and its successors will plug into and interact with the ocean observatory system, using the power charging systems and high speed communications delivered by the submarine networks.

Further Reading: National Science Foundation


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The Governor of the Red Sea in Egypt has decreed that the Red Sea will be the first plastic bag free Governorate with effect from 1st January 2009. This decree represents a considerable step forward in tackling the issues caused by excess rubbish and in particular plastic bags in the Red Sea.

Plastic bags pose a massive hazard to birds, turtles, dolphins and other marine creatures that are killed in alarming numbers each year after swallowing or becoming entangled in plastic bags blown out to sea. Turtles easily mistake plastic bags for yummy jellyfish. Once in the stomach, the indigestible plastic wraps itself around the intestines of the creature and it slowly starves to death.

Typically plastic bags are used for only 20 minutes before being thrown out; but they will each take up to 1,000 years to rot away. During their long decay millions of bags litter and pollute our streets, the desert, and are blown out to sea where they become a toxic plastic soup that threatens the existence of marine and wild life.

The Red Sea campaign follows many high profile campaigns in Europe to limit this most damaging form of pollution. The government in Ireland introduced a bag tax, which led to a 90 per cent reduction after its introduction in 2002. In 2007, the biggest supermarkets in France imposed a ban on free carriers. They now charge between 2p and 42p for reusable bags. This has removed millions of free bags from high streets and the French government will impose an outright ban in 2010.

Environmental group is working alongside the Governorate to suggest practical solutions and alternatives for plastic bags. As part of the campaign in support of this decree they will also be undertaking education initiatives and lobbying activities.

Further Reading: HEPCA

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Labels: environment, Red Sea