Calcification, dissolution and test properties of modern planktonic foraminifera from the central Atlantic Ocean

• Published in: Frontiers in Marine Science
• Main Authors: Zarkogiannis, Stergios D., Iwasaki, Shinya, Rae, James William Buchanan, Schmidt, Matthew W., Mortyn, P. Graham, Kontakiotis, George, Hertzberg, Jennifer E., Rickaby, Rosalind E.M.
• Other Authors: European Research Council, University of St Andrews. School of Earth & Environmental Sciences, University of St Andrews. Centre for Energy Ethics, University of St Andrews. St Andrews Isotope Geochemistry
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2022
• Subjects: Planktonic foraminifera; Shell weight; X-ray microtomography (µCT); Shell bulk density; Relative shell density; Buoyancy regulation; GC Oceanography; Aquatic Science; Oceanography; Ocean Engineering; Environmental Science (miscellaneous); Global and Planetary Change; Water Science and Technology; DAS; GC; Mid-Atlantic Ridge
• Online Access: http://hdl.handle.net/10023/25485; https://doi.org/10.3389/fmars.2022.864801

This research was supported in part by a Royal Society Newton International postdoctoral Fellowship to SZ from the Royal Society of London. JWBR acknowledges funding from the European Research Council under the European Union’s Horizon 2020 research and innovation program (grant agreement 805246). We also acknowledge support from U.K. NERC Grant (PUCCA) NE/V011049/1. The mass of well-preserved calcite in planktonic foraminifera shells provides an indication of the calcification potential of the surface ocean. Here we report the shell weight of 8 different abundant planktonic foraminifera species from a set of core-to sediments along the Mid-Atlantic Ridge. The analyses showed that near the equator, foraminifera shells of equivalent size weigh on average 1/3 less than those from the middle latitudes. The carbonate preservation state of the samples was assessed by high resolution X-ray microcomputed tomographic analyses of Globigerinoides ruber and Globorotalia truncatulinoides specimens. The specimen preservation was deemed good and does not overall explain the observed shell mass variations. However, G. ruber shell weights might be to some extent compromised by residual fine debris internal contamination. Deep dwelling species possess heavier tests than their surface-dwelling counterparts, suggesting that the weight of the foraminifera shells changes as a function of the depth habitat. Ambient seawater carbonate chemistry of declining carbonate ion concentration with depth cannot account for this interspecies difference. The results suggest a depth regulating function for plankton calcification, which is not dictated by water column acidity. Publisher PDF Peer reviewed