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Core Principles

December 2, 2016

WHOI biogeochemist Konrad Hughen (left) and research assistant Justin Ossolinski use a special underwater drill to take a core sample from a boulder coral off an island in the Chagos archipelago in the Indian Ocean. Corals build skeletons from chemical components in seawater and grow in annual layers, like tree rings, so scientists can precisely date when the skeletons formed. Back in the lab, scientists can analyze the skeleton chemistry, revealing shifts over time in sea surface temperature, salinity, nearby river runoff, and even pollution at up to weekly resolution. The longer the core, the further back in time the scientists can go. (Photo by Colleen Hansel, Woods Hole Oceanographic Institution)