Pliocene diatom and sponge spicule oxygen isotope ratios from the Bering Sea: isotopic offsets and future directions

• Published in: Climate of the Past
• Main Authors: A. M. Snelling, G. E. A. Swann, J. Pike, M. J. Leng
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2014
• Subjects: Environmental pollution; TD172-193.5; Environmental protection; TD169-171.8; Environmental sciences; GE1-350; Bering Sea
• Online Access: https://doi.org/10.5194/cp-10-1837-2014; https://doaj.org/article/896f60bbbea3441aa8645683b169ba2d

Oxygen isotope analyses of different size fractions of Pliocene diatoms (δ 18 O diatom ) from the Bering Sea show no evidence of an isotope offset and support the use of bulk diatom species samples for palaeoceanographic reconstructions. Additional samples containing concentrations of sponge spicules produce δ 18 O values several per mille (‰) lower than δ 18 O diatom with a calculated mean offset of 3.9‰ ± 1.5. This difference is significantly greater than modern-day variations in water δ 18 O through the regional water column. Despite the potential for oxygen isotope disequilibrium within δ 18 O sponge , there appears to be some similarity between δ 18 O sponge and a global stacked benthic δ 18 O foram record. This highlights the potential for δ 18 O sponge in palaeoenvironmental research at sites where carbonates are not readily preserved.