Grain‐scale stable carbon and oxygen isotopic variations of the international reference calcite, IAEA‐603

Abstract

Low-abundance opaque grains (1-2 grains out of 100 grains) have lower δ C and δ O values, suggesting that these grains should be eliminated when using IAEA-603 for single-grain (microscale) isotope analysis.

Deciphering lifelong thermal niche using otolith δ18O thermometry within supplemented lake trout (Salvelinus namaycush) populations

“…We found that the IAEA‐603 calcite contained significant isotopic heterogeneity at the sub‐nanogram sample mass provided by our SIMS instrument. This is consistent with the results reported by Nishida and Ishimura (2017) who observed variations in the isotopic compositions of IAEA‐603 at the single‐grain scale.…”

“…On the second day of our SIMS analytical sequence, we observed a clear relationship between the measured 18 O – / 16 O – ratio and the 16 O – count rate with some 2.5‰ difference in the isotopic ratio detected between the two groups of the IAEA‐603 grain types (opaque and translucent). It is noteworthy that Nishida and Ishimura (2017) found a δ 18 O value difference of only 0.28‰ between the two subpopulations they observed for IAEA‐603. However, these authors were working with test portion masses some four orders of magnitude larger than masses used in our SIMS determinations.…”

“…However, these authors were working with test portion masses some four orders of magnitude larger than masses used in our SIMS determinations. As suggested by Nishida and Ishimura (2017), the isotope ratio for individual grains of IAEA‐603 could be correlated with the optical clarity of a given grain.…”

Combining microvolume isotope analysis and numerical simulation to reproduce fish migration history

“…Otolith δ 18 O was measured using a continuous-flow isotope ratio mass spectrometry system (MICAL3c with IsoPrime 100) at the National Institute of Technology, Ibaraki College. This system allows analysis of δ 18 O from sub-microgram carbonate samples (>0.2 μg) with high precision and accuracy (Ishimura, Tsunogai, & Gamo, 2004;Ishimura et al, 2008;Kitagawa et al, 2013;Nishida & Ishimura, 2017;Oda et al, 2016;Sakamoto et al, 2017). Otolith powders reacted with phosphoric acid at 25°C, and the released CO 2 was purified and then introduced into the mass spectrometer.…”

“…Recently, however, the analysing system MICAL3c has been developed. This system requires 1/100 of the sample quantity required for conventional mass spectrometry (Ishimura, Tsunogai, & Nakagawa, 2008;Nishida & Ishimura, 2017), thereby allowing an accurate analysis of narrow growth increments in small otoliths (Sakamoto et al, 2017). Despite this drastic technical improvement, interpreting otolith δ 18 O values to estimate fish migration history remains difficult.…”