Stable carbon and oxygen isotope ratios for different test sizes of live benthic foraminifera from the Arabian Sea

DOI

We determined the stable oxygen and carbon isotopic composition of live (Rose Bengal stained) tests belonging to different size classes of two benthic foraminiferal species from the Pakistan continental margin. Samples were taken at 2 sites, with water depth of about 135 and 275 m, corresponding to the upper boundary and upper part of the core region of the oxygen minimum zone (OMZ). For Uvigerina ex gr. U. semiornata and Bolivina aff. B. dilatata, delta13C and delta18O values increased significantly with increasing test size. In the case of U. ex gr. U. semiornata, delta13C increased linearly by about 0.105 per mil for each 100-µm increment in test size, whereas delta18O increased by 0.02 to 0.06 per mil per 100 µm increment. For B. aff. B. dilatata the relationship between test size and stable isotopic composition is better described by logarithmic equations. A strong positive linear correlation is observed between delta18O and delta13C values of both taxa, with a constant ratio of delta18O and delta13C values close to 2:1. This suggests that the strong ontogenetic effect is mainly caused by kinetic isotope fractionation during CO2 uptake. Our data underline the necessity to base longer delta18O and delta13C isotope records derived from benthic foraminifera on size windows of 100 µm or less. This is already common practice in down-core isotopic studies of planktonic foraminifera.

Supplement to: Schumacher, Stefanie; Jorissen, Frans J; Mackensen, Andreas; Gooday, Andrew J; Pays, Olivier (2010): Ontogenetic effects on stable carbon and oxygen isotopes in tests of live (Rose Bengal stained) benthic foraminifera from the Pakistan continental margin. Marine Micropaleontology, 76(3-4), 92-103

Identifier
DOI https://doi.org/10.1594/PANGAEA.707882
Related Identifier https://doi.org/10.1016/j.marmicro.2010.06.002
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.707882
Provenance
Creator Schumacher, Stefanie ORCID logo; Jorissen, Frans J ORCID logo; Mackensen, Andreas ORCID logo; Gooday, Andrew J; Pays, Olivier
Publisher PANGAEA
Publication Year 2010
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Language English
Resource Type Supplementary Publication Series of Datasets; Collection
Format application/zip
Size 10 datasets
Discipline Earth System Research
Spatial Coverage (66.568W, 23.215S, 66.720E, 23.289N); Arabian Sea
Temporal Coverage Begin 2003-03-22T00:00:00Z
Temporal Coverage End 2003-10-01T13:11:00Z