news

한어Русский языкEnglishFrançaisIndonesianSanskrit日本語DeutschPortuguêsΕλληνικάespañolItalianoSuomalainenLatina

an icicle grew downwards and froze the seabed when it touched the bottom. the starfish and sea urchins that did not have time to escape were frozen and died.

this is not a special effect, this scenario happens all the time in antarctica and it’s called “ice fingers of death.”

when winter arrives in the southern hemisphere, the seas surrounding antarctica freeze over, doubling the size of antarctica.

the good news is that the frozen surface isolates the surface temperature, keeping the sea water under the ice at around 2°c, which is 50°c higher than the surface temperature.

for tens of millions of years, there has been a relatively stable environment beneath the antarctic ice, which has allowed life to flourish.

but the bad news is that this stability is often broken by the ice finger of death.

you may be curious, how exactly are ice fingers formed?

the english word for ice is "brinicle," which is made up of "brine" salt water and "icicle" ice columns, which reflects the reason for its formation.

△ the left side is seawater ice, and the right side is freshwater ice

seawater ice is completely different from freshwater ice. seawater ice is porous, like a sponge, while freshwater ice is usually a solid block.

this is because when seawater freezes, it releases salt and other impurities, which is why it is porous.

as seawater freezes, salt is released and seeps into the surrounding seawater, making the surrounding seawater salinity and density higher.

the increase in salinity lowers the freezing temperature of these brines, while the increase in density causes these supercooled brines to sink.

because the sinking salt water is supercooled relative to the surrounding seawater, it causes the surrounding seawater to freeze, which is how the death ice finger is formed.

the death finger is just an ice tube. there is no ice inside it. the sinking supercooled salt water is inside.

in addition, not all ice fingers can extend to the seabed. some cannot even form a stable structure and collapse on their own after a short period of time. this depends on many factors, including temperature, water flow conditions, etc.

scientists have known about the existence of the "fingers of death" since the 1960s, but its formation was not captured on camera for the first time until 2011.

if conditions allow, it will grow downwards several metres every day until it touches the seafloor and spreads a layer of ice on the floor to support itself.