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Slices of history

A little goes a long way in sediment cores, but there’s not much left of this one laid out horizontally in a case. Seafloor sediment accumulates slowly as dead organisms rain down from the surface, building mere millimeters over many years. Scientists analyze a core based on the place, depth and age they want to study, and many researchers share, taking just pieces of it. Only a few slices (or ages) of dried mud remain of this seafloor core—you might say it’s nearly out of time!
(Photo by Ellen Roosen, Woods Hole Oceanographic Institution)