Stable isotope and Mg/Ca record of Globigerinoides ruger morphotypes

DOI

Tests of the planktonic foraminifer Globigerinoides ruber (white; d'Orbigny) have become a standard tool for reconstructing past oceanic environments. Paleoceanographers often utilize the Mg/Ca ratios of the foraminiferal tests for reconstructing low-latitude ocean glacial-interglacial changes in sea surface temperatures (SST). We report herein a comparison of Mg/Ca measurements on sample pairs (n = 20) of two G. ruber (white) morphotypes (G. ruber sensu stricto (s.s.) and G. ruber sensu lato (s.l.)) from surface and downcore samples of the western Pacific and Indian Oceans. G. ruber s.s. refers to specimens with spherical chambers sitting symmetrically over previous sutures with a wide, high arched aperture, whereas G. ruber s.l. refers to a more compact test with a diminutive final chamber and small aperture. The G. ruber s.s. specimens generally show significantly higher Mg/Ca ratios compared to G. ruber s.l. Our results from the Mg/Ca ratio analysis suggest that G. ruber s.l. specimens precipitated their shells in slightly colder surface waters than G. ruber s.s. specimens. This conclusion is supported by the differences in delta18O and delta13C values between the two morphotypes. Although it is still unclear if these two morphotypes represent phenotypic variants or sibling species, our findings seem to support the hypothesis of depth and/or seasonal allopatry within a single morphospecies.

Supplement to: Steinke, Stephan; Chiu, Han-Yi; Yu, Pai-Sen; Shen, Chuan Chou; Löwemark, Ludvig; Mii, Horng-Sheng; Chen, Min-Te (2005): Mg/Ca ratios of two Globigerinoides ruber (white) morphotypes: Implications for reconstructing past tropical/subtropical surface water conditions. Geochemistry, Geophysics, Geosystems, 6, Q11005

Identifier
DOI https://doi.org/10.1594/PANGAEA.738255
Related Identifier IsSupplementTo https://doi.org/10.1029/2005GC000926
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.738255
Provenance
Creator Steinke, Stephan; Chiu, Han-Yi; Yu, Pai-Sen ORCID logo; Shen, Chuan Chou ORCID logo; Löwemark, Ludvig ORCID logo; Mii, Horng-Sheng ORCID logo; Chen, Min-Te ORCID logo
Publisher PANGAEA
Publication Year 2005
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Resource Type Supplementary Publication Series of Datasets; Collection
Format application/zip
Size 4 datasets
Discipline Earth System Research
Spatial Coverage (69.045W, -13.082S, 124.413E, 23.992N); South China Sea; Timor Sea; Arabian Sea
Temporal Coverage Begin 1986-05-10T00:00:00Z
Temporal Coverage End 2001-05-24T16:34:00Z