Deglacial diatom and sponge silicon isotope records from cores MD84-551, MD88-773 and MD88-772 ...

• Main Authors: Dumont, Matthew, Pichevin, Laetitia, Geibert, Walter, Crosta, Xavier, Michel, Elisabeth, Moreton, Stephen, Dobby, Keira, Ganeshram, Raja S
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 2020
• Subjects: Deglaciation; Diatom; silicon isotope; Southern Ocean; sponge
• Online Access: https://dx.doi.org/10.1594/pangaea.911189; https://doi.pangaea.de/10.1594/PANGAEA.911189

Silicon isotope records from diatoms can be used as a proxy for the relative consumption of dissolved silicic acid (DSi) in surface waters. Silicon isotopes in sponges provide information on the concentration of DSi within the ambient seawater in which the sponges reside. Here we provide deglacial silicon isotope records from both diatoms (d30Si_diat) and sponges (d30Si_sponge) collected in three piston cores from the Southern Ocean. Isolated diatom samples were produced from bulk sediment by mechanical separation and chemical cleaning. Pure diatom samples were digested in 0.1 M NaOH before removal of matrix via cation exchange chromatography. The samples were analysed by MC-ICP-MS at the University of Edinburgh. Sponge spicules were individually picked from sediment and underwent the same analytical procedure as decribed above. We relate the d30Si_diat records to changes in the deep upwelling DSi supply and diatom demand for DSi in the Southern Ocean surface across the deglaciation. We suggest that during ...