Navigation Links
Life in a bubble
Date:7/30/2008

CAMBRIDGE, Mass. -- Hundreds of insect species spend much of their time underwater, where food may be more plentiful. MIT mathematicians have now figured out exactly how those insects breathe underwater.

By virtue of their rough, water-repellent coat, when submerged these insects trap a thin layer of air on their bodies. These bubbles not only serve as a finite oxygen store, but also allow the insects to absorb oxygen from the surrounding water.

"Some insects have adapted to life underwater by using this bubble as an external lung," said John Bush, associate professor of applied mathematics, a co-author of the recent study.

Thanks to those air bubbles, insects can stay below the surface indefinitely and dive as deep as about 30 meters, according to the study co-authored by Bush and Morris Flynn, former applied mathematics instructor. Some species, such as Neoplea striola, which are native to New England, hibernate underwater all winter long.

This phenomenon was first observed many years ago, but the MIT researchers are the first to calculate the maximum dive depths and describe how the bubbles stay intact as insects dive deeper underwater, where pressure threatens to burst them.

The new study, which appears in the Aug. 10 issue of the Journal of Fluid Mechanics, shows that there is a delicate balance between the stability of the bubble and the respiratory needs of the insect.

The air bubble's stability is maintained by hairs on the insects' abdomen, which help repel water from the surface. The hairs, along with a waxy surface coating, prevent water from flooding the spiraclestiny breathing holes on the abdomen.

The spacing of these hairs is critically important: The closer together the hairs, the greater the mechanical stability and the more pressure the bubble can withstand before collapsing.

However, mechanical stability comes at a cost. If the hairs are too close together, there is not enough surface area through which to breathe.

"Because the bubble acts as an external lung, its surface area must be sufficiently large to facilitate the exchange of gases," said Flynn, who is now an assistant professor of mechanical engineering at the University of Alberta.

The researchers developed a mathematical model that takes these factors into account and allows them to predict the range of possible dive depths. They found that there is not only a maximum depth beyond which the bubble collapses, but a minimum depth above which the bubble cannot meet the insect's respiratory needs.

Though the researchers found that the insects can go as deep as 30 meters below the surface, they rarely venture deeper than several meters, due to environmental factors such as amount of sunlight, availability of prey and the presence of predators.

The researchers first took an interest in the external lung phenomenon when they accidentally captured one of the underwater breathers while looking for water striders. A few years ago, Bush and colleagues figured out how the striders use surface tension to glide across the water's surface.

Other researchers have explored systems that could replicate the external lung on a larger scale, for possible use by diving humans. A team at Nottingham Trent University showed that a porous cavity surrounded by water-repellent material is supplied with oxygen by the thin air layer on its surface. The surface area required to support human respiration is impractically large, in excess of 100 square meters; however, other avenues for technological application exist. For example, such a device could supply the oxygen needed by fuel cells to power small autonomous underwater vehicles.


'/>"/>

Contact: Teresa Herbert
therbert@mit.edu
617-258-5403
Massachusetts Institute of Technology
Source:Eurekalert

Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/28/2016)... BANGALORE, India , April 28, 2016 /PRNewswire/ ... product subsidiary of Infosys (NYSE: INFY ), and ... global partnership that will provide end customers with ... banking and payment services.      (Logo: http://photos.prnewswire.com/prnh/20130122/589162 ... area for financial services, but it also plays a fundamental ...
(Date:4/26/2016)... 27, 2016 Research and ... Biometrics Market 2016-2020"  report to their offering.  , ... The analysts forecast the global multimodal biometrics ... during the period 2016-2020.  Multimodal biometrics ... such as the healthcare, BFSI, transportation, automotive, and ...
(Date:4/15/2016)... Research and Markets has announced ... 2016-2020,"  report to their offering.  , ... global gait biometrics market is expected to grow ... 2016-2020. Gait analysis generates multiple variables ... to compute factors that are not or cannot ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... - BIOREM Inc. (TSX-V: BRM) ("Biorem" or "the Company") announces ... Clean Technology Fund I, LP and Clean Technology Fund ... venture capital funds which together hold approximately 59% of ... as converted basis), that they have entered into an ... in Biorem to TUS Holdings Co. Ltd. ("TUS") (en.tusholdings.com) ...
(Date:6/27/2016)... N.C. (PRWEB) , ... June 27, 2016 , ... ... commercial operations for Amgen, will join the faculty of the University of ... as adjunct professor of strategy and entrepreneurship at UNC Kenan-Flagler, with a focus ...
(Date:6/24/2016)... ... June 24, 2016 , ... While the majority of commercial spectrophotometers and ... and the 6000i models are higher end machines that use the more unconventional z-dimension ... light beam from the bottom of the cuvette holder. , FireflySci has developed ...
(Date:6/23/2016)... 23, 2016 /PRNewswire/ - FACIT has announced the ... biotechnology company, Propellon Therapeutics Inc. ("Propellon" or ... of a portfolio of first-in-class WDR5 inhibitors for ... as WDR5 represent an exciting class of therapies, ... medicine for cancer patients. Substantial advances have been ...
Breaking Biology Technology: