Identification of ventilated and submarine glacial meltwaters in the Amundsen Sea, Antarctica, using noble gases

• Published in: Frontiers in Marine Science
• Main Authors: DongYoub Shin, Doshik Hahm, Tae-Wan Kim, Tae Siek Rhee, SangHoon Lee, Keyhong Park, Jisoo Park, Young Shin Kwon, Mi Seon Kim, Tongsup Lee
• Format: Article in Journal/Newspaper
• Language: English
• Published: Frontiers Media S.A. 2022
• Subjects: glacial meltwater; noble gases; optimum multiparameter analysis; Amundsen Sea; basal melting; meteoric water; Science; Q; General. Including nature conservation; geographical distribution; QH1-199.5; Getz; Dotson Ice Shelf; Dotson-Getz Trough; Antarc*; Antarctica; Ice Shelf; Ice Shelves
• Online Access: https://doi.org/10.3389/fmars.2022.951471; https://doaj.org/article/7df4d2d370ff405d90159b073850a80d

To delineate the glacial meltwater distribution, we used five noble gases for optimum multiparameter analysis (OMPA) of the water masses in the Dotson-Getz Trough (DGT), Amundsen Sea. The increased number of tracers allowed us to define potential source waters at the surface, which have not been possible with a small set of tracers. The highest submarine meltwater (SMW) fraction (~0.6%) was present at the depth of ~450 m near the Dotson Ice Shelf. The SMW appeared to travel beyond the continental shelf break along an isopycnal layer. Air-equilibrated freshwater (up to 1.5%), presumably ventilated SMW (VMW) and surface melts, was present in the surface layer (<100 m). The distribution of SMW indicates that upwelled SMW, known as an important carrier of iron to the upper layer, amounts for 29% of the SMW in the DGT. The clear separation of VMW from SMW enabled partitioning of meltwater into locally-produced and upstream fractions and estimation of the basal melting of 53 – 94 Gt yr-1 for the adjacent ice shelves, assuming that the SMW fractions represent accumulation since the previous Winter Water formation. The Meteoric Water (MET) fractions, consisting of SMW and VMW, comprised 24% of those derived from oxygen isotopes, indicating that the annual input from basal melting is far less than the inventory of meteoric water, represented by MET.