Saving the Elephants: Fighting Illegal Poaching by Carbon-14 Dating

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by MatthewGD
Last updated 5 years ago

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Science
Subject:
Chemistry

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Saving the Elephants: Fighting Illegal Poaching by Carbon-14 Dating

Saving the Elephants: Fighting Illegal Poaching by Carbon-14 Dating

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This information can be used to identify if a piece of ivory was taken from an elephant illegally (before the trade of raw ivory was banned in 1975 for Asian elephants and in 1989 for African elephants) and thereby punish those who illegally slaughter elephants.

Instead of looking at the rate of carbon-14 decay, these researchers used a technique called accelerator mass spectrometry (AMS). Here, cesium atoms bombard the material under question to release carbon atoms, which allows the ratio of carbon-14 to carbon-12 in the material to be measured.

The researchers analyzed 29 animal and plant tissues of known age collected between 1905 to 2008. It was found that tissues formed at the same time had the same carbon-14 levels, and the grasses and the animals that ate them had the same levels as well.

Consequently, this newly developed AMS method can be used to identify the year that animals killed after 1955 died and thereby determine if they were poached. Cool, right!?

What They Did

What They Found

How is this possible? Let's start with this video to look at how carbon-14 dating works for fossils.

Can carbon-14 dating be used to determine the year an animal died and thereby fight illegal poaching?

Yes! Researchers at the University of Utah have devised a method to detect the amount of carbon-14 in the tusks, teeth and hair of various animals, including elephants and hippos, to determine the year the animal died.

Neutrons from open-air nuclear bomb tests performed by the US and Soviet between 1952 and 1962 bombarded the atmosphere's nitrogen to turn some of it into carbon-14, shown in the figure to the left. This caused a peak in the atmosphere's carbon-14 levels, which in turn increased the amount of carbon-14 in plants and animals. These levels have since been declining, resulting in a graph called a "bomb curve". By looking at the ratio of carbon-14 to carbon-12, the researchers were able to use the bomb curve to determine the age of the samples (within about a one-year range).

The news article "Age and legality of ivory revealed by carbon-14 dating can fight poachers" can be found here

The oldest samples, obtained from animals that died between 1905 and 1953, were found to have very low amounts of carbon-14 as compared to the other samples.

But why?


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