Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study examines how diving marine mammals manage decompression

22.12.2011
Any diver returning from ocean depths knows about the hazard of decompression sickness (DCS) or "the bends."

As the diver ascends and the ocean pressure decreases, gases that were absorbed by the body during the dive, come out of solution and, if the ascent is too rapid, can cause bubbles to form in the body. DCS causes many symptoms, and its effects may vary from joint pain and rashes to paralysis and death.

But how do marine mammals, whose very survival depends on regular diving, manage to avoid DCS? Do they, indeed, avoid it?

In April 2010, the Woods Hole Oceanographic Institution's Marine Mammal Center (MMC) invited the world's experts in human diving and marine-mammal diving physiology to convene for a three-day workshop to discuss the issue of how marine mammals manage gas under pressure. Twenty-eight researchers discussed and debated the current state of knowledge on diving marine mammal gas kinetics—the rates of the change in the concentration of gases in their bodies.

The workshop resulted in a paper, "Deadly diving? Physiological and behavioural management of decompression stress in diving mammals," which was published Dec. 21, 2011, online in the Proceedings of the Royal Society B.

"Until recently the dogma was that marine mammals have anatomical and physiological and behavioral adaptations to make the bends not a problem," said MMC Director Michael Moore. "There is no evidence that marine mammals get the bends routinely, but a look at the most recent studies suggest that they are actively avoiding rather than simply not having issues with decompression."

Researchers began to question the conventional wisdom after examining beaked whales that had stranded on the Canary Islands in 2002. A necropsy of those animals turned up evidence of damage from gas bubbles. The animals had stranded after exposure to sonar from nearby naval exercises. This led scientists to think that diving marine mammals might deal with the presence of nitrogen bubbles more frequently than previously thought, and that the animals' response strategies might involve physiological trade-offs depending on situational variables. In other words, the animals likely manage their nitrogen load and probably have greater variation in their blood nitrogen levels than previously believed.

Because the animals spend so much time below the ocean's surface, understanding the behavior of diving marine mammals is quite challenging. The use of innovative technology is helping to advance the science. At WHOI, scientists have used a CT scanner to examine marine mammal cadavers at different pressures to better understand the behavior of gases in the lungs and "get some idea at what depth the anatomy is shut off from further pressure-kinetics issues," Moore said. For other studies, Moore and his colleagues were able to acquire a portable veterinary ultrasound unit to look at the presence or absence of gas in live, stranded dolphins.

There's still a lot to be learned, including whether live animals have circulating bubbles in their systems that they are managing. If they do, says Moore, noise impacts and other stressors that push the animal from a normal management situation to an abnormal situation become more of a concern. "When a human diver has some bubble issues, what will they do? They will either climb into a recompression chamber so that they can recompress and then come back more slowly, or they'll just grab another tank and go back down for a while and . . . and just let things sort themselves out. What does a dolphin do normally when it's surfaced? The next things to do is to dive, and the one place you can't do that is in shallow water or most particularly if you are beached."

The Woods Hole Oceanographic Institution is a private, independent, non-profit 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.

WHOI Media Relations | EurekAlert!
Further information:
http://www.whoi.edu

More articles from Studies and Analyses:

nachricht Smart Data Transformation – Surfing the Big Wave
02.12.2016 | Fraunhofer-Institut für Angewandte Informationstechnik FIT

nachricht Climate change could outpace EPA Lake Champlain protections
18.11.2016 | University of Vermont

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>