Continuous seawater isotopic (δ18O, δD, and d-excess) observations from 2021 Arctic cruise on United States Coast Guard Cutter Healy

The dataset presented here includes isotopic measurements (δ18O, δD, and deuterium excess) of seawater to assess contributions of freshwater and identify different ocean water masses during a 2021 Arctic cruise on board the United States Coast Guard Cutter (USCGC) Healy. The cruise (HLY21TD, HLY2101) began in Seward, Alaska, sailed north around Alaska, through the Northwest Passage and into Baffin Bay, and performed numerous transects of Baffin Bay, the Labrador Sea, and along the Greenland coast. The isotopic measurements are made continuously (29 Aug – 10 Oct) on seawater sampled through the underway along the cruise track. These measurements can be used to identify and quantify sources of freshwater and partition different ocean water masses in order to help better understand changing ocean water composition and circulation.