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Tiny animal carcasses found in buried Antarctic lake

nature.com

1–10 of 22 posts

Re: Tiny animal carcasses found in buried Antarctic lake

#6
I wonder how carbon dating works in this case. My understanding is that the dating method depends on the organism interacting with the carbon in the atmosphere during its lifetime (where carbon-14 is produced by cosmic rays). The interaction stops after organism dies, after which the level of carbon-14 in its body starts to decay.

But here the whole ecosystem was supposedly isolated from the atmosphere for at least 10k years. Wouldn't all organisms, both alive and dead, just have the same (decaying) level of carbon-14 after isolation happened?

EDIT: expanded for clarity.

Re: Tiny animal carcasses found in buried Antarctic lake

#7
post #6

I wonder how carbon dating works in this case. My understanding is that the dating method depends on the organism interacting with the carbon in the atmosphere during its lifetime (where carbon-14 is produced by cosmic rays). The interaction stops after organism dies, after which the level of carbon-14 in its body starts to decay. But here the whole ecosystem was supposedly isolated from the atmosphere for at least 1…

I think you have it backwards -- carbon works by some organic material not interacting with the atmosphere. Atmospheric CO2 has a relatively constant proportion of carbon-14. Once it stops interacting with the atmosphere it begins to decay and have a different proportion than atmospheric carbon.

Re: Tiny animal carcasses found in buried Antarctic lake

#9

Tardigrades are pretty well known for their toughness - I wonder what the odds of one surviving a 10,000 year freeze is.

i think it's unlikely in this case- all the tardigrade toughness comes from entering the cryptobiotic state (extreme desiccation) while I believe all these samples were in water or ice.

Re: Tiny animal carcasses found in buried Antarctic lake

#10
post #7
post #6

I wonder how carbon dating works in this case. My understanding is that the dating method depends on the organism interacting with the carbon in the atmosphere during its lifetime (where carbon-14 is produced by cosmic rays). The interaction stops after organism dies, after which the level of carbon-14 in its body starts to decay. But here the whole ecosystem was supposedly isolated from the atmosphere for at least 1…

I think you have it backwards -- carbon works by some organic material not interacting with the atmosphere. Atmospheric CO2 has a relatively constant proportion of carbon-14. Once it stops interacting with the atmosphere it begins to decay and have a different proportion than atmospheric carbon.

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