CFCs: those man-made chemicals emitted by hairspray cans and refrigerators of the 1960s. What am I doing talking about those out at sea? Well, CFCs are the “unintentional tracer” of the ocean!
CFCs were invented to replace toxic chemicals that were being used as refrigerants. However, even though CFCs are non-toxic humans, they can cause serious damage when they enter the upper atmosphere. The upper atmosphere is the area that includes our ozone layer, which protects Earth and regulates the surface temperature by absorbing ultraviolet radiation from the sun. Once it was discovered that CFCs were creating holes in the ozone layer, governments started to ban the production and usage of CFCs. Since 1996, industries have phased out CFCs and the amount of CFCs in the atmosphere has started to decline. |
And this is where it gets fun for us- even though they are no longer being used, their longer half-life means that they will exist in the atmosphere for many years to come. Well, the ocean and the atmosphere are always in constant contact and interacting by exchanging gases. The ocean takes up CFCs, which get carried with the currents. CFCs act like a dye in ocean currents that scientist can measure and track. Determining the age and the amount of CFCs in the water column can tell us about the rates and pathways of ocean circulation and mixing patterns. They allow us to track the age of the water and they provide us a clue as to when it last came in contact with the atmosphere. Magic! |
Onboard, the CFC group gets first dibs at sampling the ocean water we bring up. Because they are measuring these chemicals at such small concentrations, they need to capture the water from the Niskins as quickly and efficiently as possible, without allowing it to interact with the air, as that would contaminate the sample. The concentration of CFCs are then measured by passing the sample through a gas chromatogram.
Onboard, the CFC group gets first dibs at sampling the ocean water we bring up. Because they are measuring these chemicals at such small concentrations, they need to capture the water from the Niskins as quickly and efficiently as possible, without allowing it to interact with the air, as that would contaminate the sample. The concentration of CFCs are then measured by passing the sample through a gas chromatogram.