Posts Tagged ‘marine biology’

Exploring Energy Conservation Through Shark Research

Sunday, August 10th, 2008

Web address:
     http://www.sciencedaily.com/releases/2007/11/
     071130155548.htm 

Dr. Amy Lang and a graduate student work in UA’s water tunnel lab researching skin friction over solid surfaces. (Credit: University of Alabama Photography)ScienceDaily (Dec. 1, 2007) — The stars of the “Jaws” films–sharks–have recently become the subject of a University of Alabama engineering research project. Conducted by Dr. Amy Lang, assistant professor of aerospace engineering and mechanics, the project explores energy conservation and boundary layer control in regard to a shark’s surface.

The project findings will allow researchers to explore natural solutions for the reduction of skin friction over solid surfaces, which could result in new innovations and applications concerning energy conservation. This research will not only provide a greater understanding of the evolutionary development of sharks, but it will also investigate methods of flow control and drag reduction that can be easily applied to mobile vehicles.

Research has shown the issue of reducing drag over solid surfaces can save thousands of dollars. For example, it is estimated that even a 1 percent reduction in drag can save an airline company up to $200,000 and at least 25,000 gallons of fuel per year per aircraft. The resulting reduction in emissions into the air is equally impressive.

Funded through a National Science Foundation Small Grant, the project is investigating the boundary layer flow over a surface that mimics the skin of a fast-swimming shark. The boundary layer is the area closest to the surface where viscous conditions cause drag–in this instance a shark’s skin.

Lang hopes to explain why fast sharks that swim upwards of 60 mph have smaller denticles, or scales, than slower shark species. Evidence suggests that sharks with smaller denticles have the ability to stick out their scales when they swim, allowing them to swim faster and creating a unique surface pattern on the skin that results in various mechanisms of boundary layer control.

“We hope to explain how a shark’s skin controls the boundary layer to decrease drag and swim faster,” said Lang. “If we can successfully show there is a significant effect, future applications to reduce drag of aircraft and underwater vehicles could be possible.”

Lang’s research is being conducted using a water tunnel facility in Hardaway Hall. The water tunnel lab can increase the shark skin geometry by 100 times with a corresponding decrease in flow over the model. This makes the flow over the skin observable, and it allows for the visualization and measurement of flow using modern experimental techniques.

In addition to the National Science Foundation Small Grant, Lang recently received a Lindbergh Grant for this research project. Lindbergh Grants are made in amounts up to $10,580, a symbolic amount representing the cost of building Charles Lindbergh’s plane, the Spirit of St. Louis.
University of Alabama (2007, December 1). Exploring Energy Conservation Through Shark Research. ScienceDaily. Retrieved August 10, 2008, from http://www.sciencedaily.com­ /releases/2007/11/071130155548.htm

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Tiny Starfish Inhabit Undersea Volcano

Monday, May 19th, 2008

By RAY LILLEY

AP
Posted: 2008-05-19 10:55:31
WELLINGTON, New Zealand (May 19) - Marine scientists surveying a large undersea mountain chain were amazed to find millions of tiny starfish swirling their arms to capture food in the undersea current.

Photo Gallery

Tiny starfish, May 18

NIWA / AP

New Zealand marine scientists found millions of tiny starfish trying to capture food in a large string of underwater volcanoes. The “sheer volume” of the starfish “challenged what we as scientists thought we knew,” said one researcher. Click through the photos to see sightings of other rare creatures.

An expedition by 19 scientists, including five from Australia, studied the geology and biology of eight Macquarie Ridge sea mounts. They are part of a string of underwater volcanoes - dormant for millions of years - that stretches 875 miles from south of New Zealand toward Antarctica.

The scientists also investigated the world’s biggest ocean current - the Antarctic Circumpolar Current - amid expectations they would find evidence of climate change in the Southern Ocean.

While the expedition’s cameras found a wide range of corals, a high density of cardinal fish and the huge coral, the vast collection of brittle stars was the highlight of the voyage.

“I’ve personally never seen anything like this - all these animals, the sheer volume - all waiting for food from the current,” expedition member and marine biologist Dr. Mireille Consalvey said Monday. “It challenged what we as scientists thought we knew.”

Expedition leader and marine biologist Ashley Rowden said starfish usually cover only slopes away from the top of the undersea mountains.

“It got us excited as soon as we saw it,” Rowden said of the site, dubbed “Brittle Star City.”

The starfish are about 0.4 inch across, with arms about 2 inches long.

The expedition began March 26 and returned to port in New Zealand’s capital Wellington on April 26.

Melbourne-based marine biologist Tim O’Hara, a brittle star specialist, said the vast collection of brittle stars, or ophiuroid ophiacantha, is “like a relic of ancient times.”

“Normally fish would prey on them and eat them … so for whatever reason there’s a lack of fish predation there and it’s seen this particular animal flourish,” he said.

O’Hara, who was not part of the voyage, said the speed of the sea current in the area may partly explain why fish were not feeding on the tiny animals.

The Circumpolar Current merges the waters of the Atlantic, Indian and Pacific oceans and carries up to 150 times the volume of water flowing in all the world’s rivers, oceanographer Mike Williams said.

Australian oceanographer Steve Rintoul, who was not involved in the expedition, said there have been few measurements of the Antarctic Circumpolar Current, which “strongly influences regional and global climate” by carrying vast amounts of water and heat across oceans.

Fewer than 200 of the world’s estimated 100,000 sea mounts that rise more than a half a mile above the sea floor have been studied in any detail.

Copyright 2008 The Associated Press

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