Original Research ARTICLE
Light impacts Mg incorporation in the benthic foraminifer Amphistegina lessonii
- 1Department of Ocean Systems, Royal Netherlands Institute for Sea Research (NIOZ), Netherlands
- 2Utrecht University, Netherlands
The ratio of Mg to Ca in foraminiferal calcium carbonate (Mg/Cacc) is a popular tool to reconstruct past sea water temperatures. Its application is being complicated by other environmental factors affecting the Mg/Cacc, including salinity and the ratio between sea water [Mg2+] and [Ca2+]. Furthermore, there is considerable intra-specimen variability in Mg/Ca in the form of alternating high- and low-concentration bands. This banding has recently been linked to diurnal cyclicity, in which bands with relatively high Mg/Ca are precipitated during night time. Here we show that light not only impacts variability due to banding but also significantly affects average chamber Mg/Ca in the large benthic, symbiont-bearing foraminifer Amphistegina lessonii. These ratios are higher in foraminifera that calcify for a longer time in the dark, with a difference in Mg/Ca of 23 mmol/mol between carbonate formed completely in the dark versus completely in the light. We propose that individual timing of chamber formation and thus presence or absence of light during calcification is an important driver of inter-specimen variability in foraminiferal Mg/Ca.
Keywords: Mg/Ca carbonates, Foraminifera (benthic), Light - dark, LA-IC-MS data, paleoclimate proxy
Received: 08 Apr 2019;
Accepted: 12 Jul 2019.
Edited by:Benoit Thibodeau, The University of Hong Kong, Hong Kong
Reviewed by:Dirk De Beer, Max-Planck-Gesellschaft (MPG), Germany
Kaoru Kubota, Japan Agency for Marine-Earth Science and Technology, Japan
Copyright: © 2019 Dämmer, de Nooijer and Reichart. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Mx. Linda K. Dämmer, Department of Ocean Systems, Royal Netherlands Institute for Sea Research (NIOZ), Texel, Netherlands, Linda.daemmer@NIOZ.nl