Li partitioning in the benthic foraminifera Amphistegina lessonii. (19th December 2015)

• Record Type: Journal Article
• Authors: Langer, Gerald; Sadekov, Aleksey; Thoms, Silke; Mewes, Antje; Nehrke, Gernot; Greaves, Mervyn; Misra, Sambuddha; Bijma, Jelle; Elderfield, Henry
• Is Part Of: Geochemistry, geophysics, geosystems. Volume 16:Number 12(2015:Dec.)
• Page Start: 4275
• Page End: 4279
• Publication Date: 2015-12-19
• Subjects: Li partitioning -- foraminifera -- biomineralization; Geochemistry -- Periodicals; Geophysics -- Periodicals; Earth sciences -- Periodicals; 550.5
• DOI: 10.1002/2015GC006134
• Languages: English
• ISSNs: 1525-2027

Abstract

Abstract: The shallow water benthic foraminifer Amphistegina lessonii was grown in seawater of variable Li and Ca concentration and shell Li/Ca was determined by means of LA‐ICPMS. Shell Li/Ca is positively correlated to seawater Li/Ca only when the Li concentration of seawater is changed. If the seawater Ca concentration is changed, shell Li/Ca remains constant. This indicates that Li does not compete with Ca for incorporation in the shell of A. lessonii . A recently proposed calcification model can be applied to divalent cations (e.g., Mg and Sr), which compete for binding sites of ion transporters and positions in the calcite lattice. By contrast, the transport pathway of monovalent cations such as Li is probably diffusion based (e.g., ion‐channels), and monovalent cations do not compete with Ca for a position in the calcite lattice. Here we present a new model for Li partitioning into foraminiferal calcite which predicts our experimental results and should also be applicable to other alkali metals. Key Points: Li partitioning in A. lessonii fundamentally differs from Mg and Sr partitioning The Li partitioning coefficient should be based on the seawater Li concentration A new cellular transport model for alkali metals is presented