whale diving ability

From: Phil Clapham (pclapham@whsun1.wh.whoi.edu)
Date: Fri Mar 14 2003 - 06:35:04 EST

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    Hi Robert:

    The sperm whale, as you may know, is the deepest diver of all the whales
    and can get down to probably 9-10,000 feet on dives that in extreme cases
    last two hours. As you say, this presents some unique challenges for an
    air-breathing mammal.
    It's not entirely clear how they do this. In terms of the physiology,
    sperm whales have many times more oxygen in their muscle tissue - bound as
    myoglobin - than we do. In fact, sperm whale muscle is actually black
    rather than dark red because it's so heavily oxygenated. Sperm whale
    tissue can also respire anaerobically for much longer than ours can.
    In terms of the pressure issue, there are a couple of things going on.
    Two of the big problems with human divers and baropressure is that a)
    they're breathing pressurized air from tanks; and b) they can't collapse
    their lungs. Thus, when they dive that air goes under increased pressure
    and when they ascend too quickly it (actually the mitrogen in the air)
    forms bubbles in the blood, which can be fatal (the bends). It's the same
    thing as shaking up a can of soda and then taking the top off - the gas
    (CO2) is pressurized by the shaking, then the sudden release of pressure
    with the cap being taken off causes the gas to form bubbles. Sperm whales
    get around this problem by not breathing pressurized air - they're taking
    down regular air, distributed widely about the muscles and elsewhere.
    Since whales (like us) are made up mostly of water in their tissues, the
    pressure isnt as much a problem as you'd think for most of the tissue,
    since water is essentially incompressible. But it's the body cavities -
    notably the lungs - that present the problem during the pressure of a
    dive. Unlike humans, in whom the lung cavity is subject to increasing
    pressure during a dive and can't react to it, sperm whales can collapse
    their lungs, so that there's no large air space in their body.
    Those are the basics, but it's still a bit of a stretch of one's
    imagination to think about an air-breathing mammal subject to over 300
    atmospheres of pressure!
    By the way, recent tagging work by Woods Hole Oceanographic Institution
    has shown that sperm whales are upside down most of the time when they're
    at the bottom of a dive; no one is entirely sure why!
    Hope this helps.

    Phil Clapham

    -- 
    Phillip J. Clapham, Ph.D.
    Large Whale Biology Program
    Northeast Fisheries Science Center
    166 Water Street
    Woods Hole, MA 02543
    

    Tel (508) 495-2316 Fax (508) 495-2066

    > > > Dear Sir, > > > > I am serving on active duty in the United States Navy as a nurse, and > am currently stationed at Naval Hospital Camp Lejeune in North > Carolina. I am also currently a student at UNC-W working on a dual > degree in marine biology and family practice nurse practitioner (I > read about job openings with NOAA needing FNP's as ship's doctors > while at sea and am very interested in pursuing that career option > when I finish with the NAVY) I am > writing you as the marine biology major. One of the classes I am > taking this semester is deep sea biology. I am writing a major term > paper on the deep diving abilities of the sperm whale, and am looking > for two major areas of information: what happens to barophobic > animals under increasing pressure, and how does a sperm whale counter > these effects. I appreciate your consideration in this matter and > look forward to hearing back from you. > > > > Sincerely > > > > Robert W Whitaker II > > > > > --- Christy Whitaker > > --- christywhitaker@earthlink.net > > --- EarthLink: It's your Internet.



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