What is the finger of death?

What is finger of death?


with this striking name is known to a natural phenomenon due to cold and salt that is slow, beautiful, stylish and lethal. At least for the sea creatures of the Southern Ocean.

With such a dramatic name we could expect anything. But the fact is that is well known for a natural phenomenon that occurs in Antarctica . In some specific points, thanks to the characteristics of the ocean temperatures, a spiral ice begins to grow slowly. It’s an incredibly beautiful and very, very slow performance. But also lethal. So when we saw a group of BBC managed to make a timelapse of their training. Now, we can all appreciate how this form finger death and why it is called so.


Slow but deadly

the finger of death, also known in English by brinicle ( brine , brine and icecle , icicle) is a column of ice as an iceberg, but is formed inside the water from an ice sheet. According grows there comes a point where it touches the ground and begins to spread in one direction, more or less, creating an icy trail in its wake. So far, very correct. Except for one thing: why call it, then finger of death? One of the things that has always fascinated marine biologists, probably because of its morbidity rather than another by a scientific question, is the ability to catch tens or even hundreds of creatures in its path.

finger death

of course, not talking about fish or animals whose movement is fast. So that the finger of death caught a few species need a minimum time at which water freezes around the limbs of the animal. Of course, in Antarctic waters the amount of “slow” in their movement, species is huge. This is what you have to live in subzero temperatures. The metabolism slows down , as a result of the cold. And not all animals are prepared to survive under such conditions. Only the most extreme are trained. Of course, that means in many cases that are simple species such as starfish and sea urchins, sea cucumbers and some (sea cucumbers). And none is moving too fast, so they are grazing finger of death.

tiny feet are caught and now, from there, the rest of body the video freezes in fact be seen as they move with their tiny tube feet, as small ventositas. Approaching the path of the column (or when the ice on them), these tiny feet are caught and now, from there, the rest of the body is frozen, which is a Unlike mortal. It is very interesting to note how many of these stars are trying to move away to feel the cold, or salt, ice column while lowering. If observáramos at normal speed probably will not be so impressive. But timelapse , a fast camera, images are decidedly impressive.

Why is the finger of death form?

Training this curious column brine can be explained by the temperature and the concentration of salt dissolved in water. Water freezes at temperatures below 0. But the more salt has dissolved, harder it is freezing, getting lower the freezing point . Once frozen, part of the leaves are “expelled” from the solution. With this in mind, now we go to the ice sheet. This, relatively close above ground, is in contact, on its surface, with the cold air, maintaining a temperature of about -20. However, the water temperature is -1 or -2. Thus, at one point, the water around the ice begins to freeze, creating around them a thin layer of salt (and denser) water itself seawater around them.

you can see the brine emerging from the fingertips of death with the right conditions, such training begins to bulge, creating a current that descends because of its higher density. Thus, the water begins to freeze down as more and more and more ejected brine . This forms a gap with super-cold water by being in contact with the ice up tube, but does not freeze due to the brine, which goes down. The hollow column, brine channels and grows slowly. You can see the brine emerging from the fingertips of death. It is a point where the two waters have a very large difference in salinity.

 finger of death

as it descends the column, if the soil is sufficiently close, catching up ends. Then the brine extends toward the mainstream, transmitted by channels finger of death. This way the frozen carpet is created, about ten degrees below zero , which is enough to kill even the agencies extremophiles who like to live in cold water. This phenomenon has been known since the 60s, but has not been until recently that it was possible to shoot in fast motion to enjoy an incredible image. And, of course, one must admit that the finger of death lives up to its name.


Hypertext

What is the finger of death?
Source: english  
February 17, 2016

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