Controls on planktonic foraminifera apparent calcification depths for the northern equatorial Indian Ocean

  • Within the world’s oceans, regionally distinct ecological niches develop due to differences in water temperature, nutrients, food availability, predation and light intensity. This results in differences in the vertical dispersion of planktonic foraminifera on the global scale. Understanding the controls on these modern-day distributions is important when using these organisms for paleoceanographic reconstructions. As such, this study constrains modern depth habitats for the northern equatorial Indian Ocean, for 14 planktonic foraminiferal species (G. ruber, G. elongatus, G. pyramidalis, G. rubescens, T. sacculifer, G. siphonifera, G. glutinata, N. dutertrei, G. bulloides, G. ungulata, P. obliquiloculata, G. menardii, G. hexagonus, G. scitula) using stable isotopic signatures (δ18O and δ13C) and Mg/Ca ratios. We evaluate two aspects of inferred depth habitats: (1) the significance of the apparent calcification depth (ACD) calculation method/equations and (2) regional species-specific ACD controls. Through a comparison with five global, (sub)tropical studies we found the choice of applied equation and δ18Osw significant and an important consideration when comparing with the published literature. The ACDs of the surface mixed layer and thermocline species show a tight clustering between 73–109 m water depth coinciding with the deep chlorophyll maximum (DCM). Furthermore, the ACDs for the sub-thermocline species are positioned relative to secondary peaks in the local primary production. We surmise that food source plays a key role in the relative living depths for the majority of the investigated planktonic foraminifera within this oligotrophic environment of the Maldives and elsewhere in the tropical oceans.
Author:Stephanie Stainbank, Dick Kroon, Andres Rüggeberg, Jacek RaddatzORCiDGND, Erica S. de Leau, Manlin Zhang, Silvia Spezzaferri
Pubmed Id:
Parent Title (English):PLoS one
Place of publication:Lawrence, Kan.
Contributor(s):Gerald Ganssen
Document Type:Article
Year of Completion:2019
Date of first Publication:2019/09/12
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2019/09/16
Tag:Calcite; Geochemistry; Maldives; Oceans; Plankton; Salinity; Sea water; Water columns
Issue:(9): e0222299
Page Number:34
First Page:1
Last Page:34
Copyright: © 2019 Stainbank et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Institutes:Geowissenschaften / Geographie / Geowissenschaften
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 55 Geowissenschaften, Geologie / 550 Geowissenschaften
6 Technik, Medizin, angewandte Wissenschaften / 63 Landwirtschaft / 630 Landwirtschaft und verwandte Bereiche
Licence (German):License LogoCreative Commons - Namensnennung 4.0