Benthic addition of Nd in the modern Southern Ocean and its dispersal in various water masses - results from four Polarstern expeditions EASI-1 and EASI-2

durch Marcus Gutjahr (GEOMAR Kiel)

Mittwoch 17.12.2025, 13:15 → 14:30 Europe/Berlin

8A-002 - Hörsaal Ostufer / Lecture Hall East (GEOMAR - Standort Ostufer / GEOMAR - East Shore)

Abstract:

The Southern is the only major ocean connecting all three major oceans. In terms of water masses, it is largely occupied by various water bodies forming the Antarctic Circumpolar Current (ACC), underlain in most parts by different varieties of Antarctic Bottom Water. While water masses can classically be distinguished based on physical properties (e.g., potential temperature, salinity, neutral density), it is more difficult to identify the geographic origin of individual water masses. During two major expeditions exploring the interaction of the East Antarctic Ice Sheet with Southern Ocean water masses (EASI-1 and EASI-2), an extensive set of water samples has been collected along various transects along the East Antarctic continental margin, within Prydz Bay, as well as through a sampling transect at 100°E starting in front of Denman Glacier and reaching to 45°S. In this talk, I will present the water column neodymium isotope composition (expressed in eNd), as well as neodymium and samarium concentration data. This data set traces the origin and mixing proportions of various water masses in the Indian sector of the Southern Ocean. The Nd isotopic tracer is particularly sensitive at resolving water mass interactions between water masses of the southernmost ACC and regional East Antarctic shelf waters. Studies like this here resolve the cycling of this rare earth element in the Southern Ocean, and are an essential prerequisite for any paleoceanographic investigation aiming to reconstruct basin-scale water mass circulation in the past using authigenic Nd isotopes.