Title: Frosty fingerprints: Tracing glacial meltwater in the Southern Ocean with δ¹⁸O

Abstract

Seawater oxygen isotopes (δ¹⁸O) can be used alongside salinity to understand the quantities, pathways, and upstream impacts of glacial meltwater across West Antarctica. We present studies in three different regions of West Antarctica, each leveraging seawater δ18O to a different end. In the Amundsen Sea, we analyze a time-series of δ¹⁸O spanning 1994 to 2020, identifying and quantifying the glacial meltwater in the ocean, from two of Antarctica’s most critical glaciers. In the Bellingshausen Sea, we use δ¹⁸O to identify and distinguish between different glacial meltwater sources and trace their pathways across the continental shelf. Finally, in the Ross Sea, we examine the impact of melt from the Amundsen and Bellingshausen Seas on the upstream waters in the Ross Sea from 1976 to 2018, using δ¹⁸O to identify changes in shelf water formation processes. This research highlights the influence of glacial meltwater on Antarctic hydrography and ocean-ice shelf interactions, emphasizing the value of δ¹⁸O in monitoring glacial melt, and its influence on the wider Southern Ocean in a warming world.