Tim Kenna, a researcher at Columbia University’s Lamont-Doherty Earth Observatory, prepares to be lowered onto an ice floe by crane to collect ice samples Sept. 8, 2015, in the Arctic Ocean. Kenna is underway on Coast Guard Cutter Healy, as the ship supports the National Science Foundation-funded Arctic GEOTRACES, part of an international effort to study the distribution of trace elements in the world's oceans. (U.S. Coast Guard photo by Petty Officer 2nd Class Cory J. Mendenhall)