sail-world.com
 
 
News Home Cruising Photo Gallery Video Gallery

 

Sail-World.com : How dolphins handle 'the bends'

How dolphins handle 'the bends'

'A common dolphin is examined by ultrasound after stranding alive on Cape Cod, Mass. (Image under NOAA Stranding Agreement with International Fund for Animal Welfare (IFAW)'    WHOI Graphic Services

Scientist are aware that the blood and tissue of some deceased beaked whales stranded in the vicinity of naval sonar exercises are riddled with bubbles. It is also well-known that human divers can suffer from bubble induced decompression sickness, more often referred to as the bends.

What researchers know comparatively little about is how living marine mammals handle the compression of lung gas as they dive deep and then resurface.

Now, in a study published online in the Proceedings of the Royal Society B, a team that includes researchers from the Woods Hole Oceanographic Institution (WHOI) has confirmed that bubbles do form in live, stranded dolphins. But in many cases, those animals are able to 'manage' those bubbles and can resume relatively normal lives of swimming and diving in the ocean.

'Evidence suggests that live dolphins that have been stranded have bubbles that appear not clinically significant,' said Michael Moore, a senior research specialist in biology and director of the WHOI Marine Mammal Center.

The multi-institutional research team, led by Sophie Dennison of the Marine Mammal Center in Sausalito Ca., along with collaborators from WHOI, the International Fund for Animal Welfare (IFAW), and the Chicago Zoological Society, performed ultrasound scans on 22 live stranded and capture-release dolphins. The researchers examined the liver, kidneys, eyes, and blubber-muscle interface.

They found gas in the kidneys of 21 of the live stranded dolphins and in some liver veins of two of the animals. Nine then died or were euthanized, and the presence of bubbles was corroborated by computer tomography and necropsy examinations. Of the remaining 13 that were released, 11 did not re-strand.

The researchers said that off-gassing of supersaturated blood and tissues was the most likely origin for the gas bubbles. 'In contrast to marine mammals repeatedly diving in the wild, stranded animals are unable to recompress by diving, and thus may form bubbles,' they report in their paper. 'Since the majority of beached dolphins released did not re-strand, it also suggests that minor bubble formation is tolerated and will not lead to clinically significant decompression sickness.'

A common dolphin is examined by ultrasound after stranding alive on Cape Cod, Mass. (Image under NOAA Stranding Agreement with International Fund for Animal Welfare (IFAW) -  © International Fund for Animal Welfare  

The results, Moore said, 'suggest that dolphins are possibly managing bubbles routinely to avoid decompression sickness, also known as the bends. Humans likewise manage 'silent bubbles.’' Only a minority of human divers that get bubbles, he added, get the bends.

Moore said it was the observation of bubbles in deceased beaked whales that led to the current study. 'In routine decompression, the animal exhibits normal physiology and experiences few bubbles,' he said. 'But acoustic stressors, such as sonar, seem to change normal bubble management.'

'Beaked whales are stranding atypically when exposed to sonar,' Moore said. 'The beaked whale mortality events have led the current generation of marine mammal physiologists to revisit the question of how marine mammals manage the issue of lung gas being compressed as they dive deeper,' he said.

'Above the depth of alveolar collapse, a depth at which the gas-exchange surface of the lung is no longer inflated, increasing pressure with depth can cause gases to dissolve in the body; the gases then come back out of solution as they resurface. If this decompression is uncontrolled, bubbles can form. In humans such bubbles can cause joint pain that is relieved by 'bending' limb joints - hence the popular name. It was thought that marine mammals were immune to such problems, but the beaked whale cases reopened this assumption to fresh scrutiny.'

Moore said the study, which was funded by the U.S. Office of Naval Research and IFAW, is but one piece to the puzzle of possible effects of how human or environmentally induced changes to ocean conditions might affect the health and behavior of dolphins. Nevertheless, he said, 'We have shone a bit more light on bubbles in marine mammals.'

Woods Hole Oceanographic Institution website

The Woods Hole Oceanographic Institution is a private, independent organization in Falmouth, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the ocean and its interaction with the Earth as a whole, and to communicate a basic understanding of the ocean's role in the changing global environment.




by Woods Hole Oceanographic Institution

  

Click on the FB Like link to post this story to your FB wall

http://www.sail-world.com/index.cfm?nid=90040

9:19 PM Thu 27 Oct 2011 GMT






Click here for printer friendly version
Click here to send us feedback or comments about this story.


News - USA and the World

Express 27 National Championship overall + Video by Erik Simonson, Pressure-Drop.US,














America's Cup: Louis Vuitton Cup's Yves Carcelle dies at 66 *Feature by Richard Gladwell/Sail-World.com/nz,












Audi Melges 20 World Championship - ‘Samba Pa Ti’ crowned champion by International Audi Melges 20 Class Association,










Audi Melges 20 World Championship - Final race to decide champion by International Audi Melges 20 Class Association,










Fort Lauderdale International Boat Show - 13 things to See and do by Fort Lauderdale International Boat Show,




Volvo Ocean Race: Update from Team Vestas Wind in images by Richard Gladwell/Sail-World.com/nz,








Audi Melges 20 World Championship - Classic Garda conditions on day 2 by International Audi Melges 20 Class Association,








Audi Melges 20 World Championship - Day 2 images by Stefano Gattini
Volvo Ocean Race - Two more join Dongfeng Race Team
OHPRI Teen Summer Camps make a splash
East to West: A profile of Volvo Ocean Race crew Team Dongfeng
Extreme Sailing Series - First-ever Turkish team to race in Istanbul
Audi Melges 20 World Championship - Race 4 images by Max Ranchi
New Around Britain and Ireland Monohull 40ft and less world record
Detroit Cup - Fifth place finish a difficult result for Neptune Racing
Audi Melges 20 World Championship - Alessandro Rombelli's 'STIG' leads
Volvo Ocean Race: Call of Duty comes first for Team Alvimedica
Audi Melges 20 World Championship - Day 1 images by Stefano Gattini
Helping boaters understand weather basics
PWA Alacati World Cup - Exciting finish on day 2
Match 40s find the surface again + Video
Audi Melges 20 World Championship - Day 1 images by Max Ranchi
Clagett Regatta names first Executive Director
Transatlantic Race - Fleet expanded for 2015 edition
IFDS World Championship overall
Anna Tunnicliffe: Alinghi finishes second - Extreme Sailing Series
2014 18' Skiff International Regatta - Day 2
2014 Audi Melges 20 World Championship - It's go time in Garda   
2nd Annual Keith Dinsmoor Regatta September 13-14   
Aldo Alessio Regatta - Three days of tight racing   
PWA Alacati World Cup - First blood to Van Der Steen and Offringa   
Oakcliff Sailing hosts the Nacra 17, 49er and 49erFX Nationals + Video   
International 18ft Skiff Regatta underway on San Francisco Bay   
Maxi Yacht Rolex Cup 2014 - Quality fleet for Maxi Classic   
Sailing Champions League - which is Europe's best sailing club?   
Weta fun at the Wine & Roses Regatta   
Extreme Sailing Series: The Wave, Muscat claims victory on Cardiff Bay   
International 14 World Championships 2015: Not just for boys   
Rio de Janeiro achieves 50% treatment of sewage outflow *Feature   
2014 AWT Quatro Desert Showdown - Event memorable videos   
2014 18' Skiff Int Regatta: Day 1 at San Francisco - Reversal on beach   
Emirates Team NZ: Last race boost cannot save team from table bottom   
PWA Alacati World Cup - Furious slalom is upon us   
J/111 World Championships - The Winner is Shmokin Joe!   
J/24 US National Championship - Victory for Will Welles’ Cougar   
Extreme Sailing Series: View the Final Day's action - Replay   
NYYC Grandmasters Team Race - Reign continues for Noroton Yacht Club   


For this week's complete news stories select    Last 7 Days
   Search All News
For last month's complete news stories select    Last 30 Days
   Archive News







Sail-World.com  


















Switch Default Region to:

Social Media

Asia

Australia

Canada

Europe

New Zealand

United Kingdom


http://www.sail-world.com/event_images/image/Twitter_logo_small.png http://www.sail-world.com/event_images/image/FaceBook-icon.png  http://www.sail-world.com/event_images/image/RSS-Icon.png

United States

Cruising Northern

Cruising Southern

MarineBusiness World

PowerBoat World

FishingBoating World

 

Contact

Commercial

News

Search

Contact Us

Advertisers Information

Submit news/events

Search Stories/Text

Feedback

Advertisers Directory

Newsletter Archive

Photo Gallery

 

Banner Advertising Details

Newsletter Subscribe

Video Gallery

Policies

 

 

 

Privacy Policy

 

 


Cookie Policy

 

 



This site and its contents are © Copyright TetraMedia and/or the original author, photographer etc. All Rights Reserved.  Photographs are copyright by law.  If you wish to use or buy a photograph contact the photographer directly.
XLXL NEW US
LocalAds   DE  ES  FR  IT