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Images: Follow the Carbon Trail

To their surprise, scientists found evidence that organic matter from massive algal blooms off Nova Scotia (visible in the satellite image above) had been transported hundreds of miles south to the bottom of the Sargasso Sea. That set the researchers on a path to find out how. (Image courtesy of the SeaWiFS Project, NASA)
One species of marine alga, Emiliania huxleyi, almost exclusively produces lipids called alkenones, which have proven quite useful for scientists tracking the movement of carbon through the oceans. The scientists have developed methods not only to date carbon-containing conglomerations, but also individual compounds that contain carbon, such as alkenones. (Photo courtesy of Tim I. Eglinton, Woods Hole Oceanographic Institution)
Alkenones preserved in seafloor sediments provide a record of the temperatures of the waters in which they were made. When seawater temperatures are warmer, Emiliania huxleyi algae produce alkenones with fewer double bonds; when temperatures are colder, they make alkenones with more double bonds. (Image courtesy of Tim I. Eglinton, Woods Hole Oceanographic Institution)
Analyzing seafloor sediments from the Bermuda Rise, scientists concluded that alkenones made off Nova Scotia were transported southward by the Deep Western Boundary Current. Off Cape Hatteras, the current intercepts the clockwise-circulating Worthington Gyre and the counterclockwise North Recirculating Gyre. The two great gyres act like interlocking cogs, drawing Nova Scotian particles from the Deep Western Boundary Current, channeling them eastward between the gyres, and carrying them onto the Bermuda Rise. (Illustration by E. Paul Oberlander, Woods Hole Oceanographic Institution)
It may be mud, but it's also a priceless sample of seafloor sediment for marine geochemists Tim Eglinton and Helen White, a MIT/WHOI Joint Program graduate student who graduated in 2005. (Photo courtesy of Tim I. Eglinton, Woods Hole Oceanographic Institution)
Eglinton and colleagues have deployed moorings equipped with sediment traps positioned to intercept particles raining from overlying surface water; particles being laterally transported eastward off the continental shelf, down the continental slope, and along the seafloor; as well as particles carried southward by the Deep Western Boundary Current. The moorings also have optical sensors that can reveal "clouds" of particles "blowing" laterally from the continental shelf'persistently in some cases and ephemerally in others. Eglinton's moorings are interspersed between other moorings in Line W, which are equipped with instruments to monitor the Deep Western Boundary Current. By analyzing the chemistry of material collected by the traps, Eglinton can determine the composition, age, and sources of carbon being exported to the ocean interior. (Illustration by E. Paul Oberlander, Woods Hole Oceanographic Institution)
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