It's Cold in the Ocean but It's Hotter Inside Every Sea Otter (nytimes.com) 25
To stay warm in frigid seas, the marine mammals rely on an unexpected use of the powerhouses of their cells. From a report: Sea otters run hot. It's not just a manner of speaking: Scientists have found that the furry mammals' metabolisms work at a rate three times what might normally be expected from a creature their size, burning swiftly through calories. They seem to be using much of that energy to generate heat, keeping themselves at a toasty 98.6 degrees Fahrenheit in the frigid ocean, where staying warm is a matter of life and death. But the details of their conversion of food and oxygen into vast reserves of heat have been obscure. Now researchers studying sea otters' muscles report that the feat involves using the mitochondria in their muscle cells in an unexpected way. Their study was published Thursday in the journal Science.
Unlike whales and polar bears, sea otters don't have a thick insulating layer of blubber, and their celebrated fur -- the thickest in the world, with up to 2.6 million hairs per square inch -- is not enough on its own to keep them alive in an ocean that can hover on the edge of freezing. Muscles generate heat as they contract, but scientists have known for some time there is another way that muscles can help animals keep warm, a cellular process with the delightful name of proton leak. Inside almost all animal cells, little pill-shaped organelles called mitochondria break down sugar molecules to extract energy. (Mitochondria are often called the powerhouses of the cell.) During the final stage of this process, protons pop through a membrane. In biology textbooks, the protons helpfully trickle through tiny spinning pores, driving them like water wheels to make adenosine triphosphate, a compound that serves as the molecular battery powering cellular processes.
Unlike whales and polar bears, sea otters don't have a thick insulating layer of blubber, and their celebrated fur -- the thickest in the world, with up to 2.6 million hairs per square inch -- is not enough on its own to keep them alive in an ocean that can hover on the edge of freezing. Muscles generate heat as they contract, but scientists have known for some time there is another way that muscles can help animals keep warm, a cellular process with the delightful name of proton leak. Inside almost all animal cells, little pill-shaped organelles called mitochondria break down sugar molecules to extract energy. (Mitochondria are often called the powerhouses of the cell.) During the final stage of this process, protons pop through a membrane. In biology textbooks, the protons helpfully trickle through tiny spinning pores, driving them like water wheels to make adenosine triphosphate, a compound that serves as the molecular battery powering cellular processes.
So, that means (Score:4, Interesting)
Sea Otters are causing global warming?
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Not going to keep much warm doing that.
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That should read, “You can freeze in the seas, but it’s hotter in an otter.” Fixed that for you.
I thought they smelled bad on the outside.
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Re: Mitochondria? (Score:1)
Oh that's great. (Score:3)
Perfect. Protons. Now we find out that otters a nuclear powered. Just one more thing to worry about I guess.
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Protons are more common than you think, actually, and form the basis of many chemical reactions.
A proton is just a hydrogen ion. That's it. H+. Strip hydrogen of its electron and all you're left with is a proton. Any acid will have an excess of H+ reducing the pH. Water splits into ions from time to time H20 --> H+ + OH- but since H+ and OH- are balanced it stays neutral (pH of 7).
And when you see
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So did you just explain the joke, or did I do that just now?
2,4-Dinitrophenol (DNP) (Score:5, Informative)
From https://en.wikipedia.org/wiki/... [wikipedia.org]
DNP acts as a protonophore, allowing protons to leak across the inner mitochondrial membrane and thus bypass ATP synthase. This makes ATP energy production less efficient. In effect, part of the energy that is normally produced from cellular respiration is wasted as heat.
DNP was used extensively in diet pills from 1933 to 1938 [...]
The factor that limits ever-increasing doses of DNP is not a lack of ATP energy production, but rather an excessive rise in body temperature due to the heat produced [...]. Accordingly, DNP overdose will cause fatal hyperthermia, with body temperature rising to as high as 43.1 C (109.6 F) shortly before death.
In light of the adverse effects and fatal hyperthermia caused by DNP when it was used clinically, the dose was slowly titrated according to personal tolerance, which varies greatly. Concerns about dangerous side-effects and rapidly developing cataracts resulted in DNP being discontinued in the United States by the end of 1938. In 1938, the FDA included DNP in a list of drugs potentially so toxic that they should not be used even under a physician's supervision.
Re: 2,4-Dinitrophenol (DNP) (Score:4, Informative)
So I've been listening to Hail Mary this week... (Score:1)
Oh look! (Score:2)
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I wish I could do the same (Score:3)
Why can't humans do the same? Wouldn't it be great to lose weight just by underdressing in the winter?
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We can, to a certain extent. We're not really heavily optimized for it though, so there are definite limits. And pushing it outside fairly narrow limits appears to be something most people don't normally do automatically. And most people treat their body's internal workings as fully automatic.
I could do it automatically as a child, being toasty warm playing in the snow in a T-shirt and shorts (to the horror of some of my mother's friends). And a couple decades later I lucked back into it after capsizing a
Read it as photons at first (Score:1)
And was wondering why I have not heard that they can glow in the dark.
Effect on lifespan (Score:2)
I've got to wonder what that higher metabolic rate does to their life span. How does their life-span compare to other mammals of a similar size?
Metabolic rate tends to be inversely correlated to lifespan to the point that, as a first-order approximation, most mammals tend to live for about the same number of heartbeats. I think that's true of many other classes of animals well, though not necessarily valid for comparing between classes.
Aha! (Score:2)
Now I know why the otter in the Copenhagen zoo always takes a nap on a bed of ice-cubes.
"Journalists" are idiots. (Score:2)
"98.6 degrees Fahrenheit"? Really? First of all, sea otter body temp is actually 100 deg F.
The idiot who wrote this thought body temp = 98.6 F for every thing on earth. Idiot.
Next, what's with the ".6"? More idiocy. That is because 37 deg C is EXACTLY 98.6 deg F. Funny how human body temp ends up being EXACTLY an integral number of degrees C. Especially when measured in the 19th century. More idiocy.