How do we science? / Science

Science during wartime: The effects of atomic bomb tests on biology, ecology, geology, and geochemistry

This Youtube video, originally posted about 3 years ago, has been making the rounds in the blogosphere as of late. It is frightening and incredible all at once. It acts as a history lesson, showing us who the players were in the arms race and even mirroring the ramp up and end of the cold war.  Looking for the fireworks? Fast forward to 4:30 and see for yourself. The US and USSR tested an absurd number of bombs from 1960-1963. Keep in mind that there are no tests of any kind recorded in this video before the bombs were dropped on Hiroshima and Nagasaki. Such is the tremendous power and danger of such a weapon, that the creatures did not test before using them on humans. Thankfully, these are the only two actual bombings.  It leaves me to wonder why on Earth we needed 2051 more tests, but such were the times. The world was at the brink (and arguably still is), but that is beyond the scope of this blog.

My big  epiphany came at about the 5 minute mark (1963). Bomb testing seems to slow around October of 1963 and becomes concentrated in a few select locations. History buffs will recognize this date as the time when the Limited Test Ban Treaty was passed. The treaty prohibited any nuclear testing that was not underground (ocean and all underwater testing was banned, thankfully). This treaty was enacted because of all of the radioactive carbon (carbon 14) that was being released at the surface and in the atmosphere. Carbon 14 obviously has negative impacts, as it is radioactive, but it also left behind a footprint, making it very useful in calibration of carbon dating, as well as nutrient cycling and the like.

esrl.noaa.gob

esrl.noaa.gov

Above ground nuclear testing peaked in the late 50’s and early 60’s. The massive spike in carbon 14 on this figure is due to this peak. After the LTBT was passed, testing decreased considerably and ceased above ground. As a result, carbon 14 values dropped back towards natural abundance, due to atmospheric exchange with the oceans and biota. This peak is very sharp and definitive and we have a great record of it. We are able to do a variety of thing with this knowledge, not least of see how long it takes for atmospheric CO2 to flow in and out of a system. This timing is clearly of importance to us now as we examine how long CO2 can be sequestered in the oceans (and how much of it can be sequestered).

Another positive to come out of bomb testing is the ability to test our radio carbon dating methods. A recent paper in PNAS explores the use of bomb carbon to detect the age of confiscated animal tissue in order to determine age of the animal from which the tissue came. Hunting restrictions are based on age of the animal and year collected.

Scientists have also used radiocarbon as a tracer in systems such as the ocean in order to calculate residence time of water masses and nutrients. A variety of other isotope concentrations were increased as a result of high energy nuclear testing as well, and they can also be used as tracers. Scientists have been able to find a positive use for the fallout of this indelible time in human history. I’m certainly not saying thank you and I hope this never happens again, but I do recognize what drives our society and accept that often we do not make incredible leaps in technology without a conflict to induce them. For example: We wouldn’t have confirmed that sea-floor spreading existed or even had a decent map of the seafloor without WWII.

For more info on “bomb carbon” check out these links:

http://www.esrl.noaa.gov/gmd/education/isotopes/bombspike.html

http://www.ncbi.nlm.nih.gov/pubmed/23818577

http://www.radiocarbon.com/carbon-dating-bomb-carbon.htm

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