Migration history of an ariid Indian catfish reconstructed by otolith Sr/Ca and <i>δ</i>¹⁸O micro-analysis

Abstract

also carry signatures of both physiological and environmental processes throughout the life history of the fish (Campana et al., 1999; Elsdon et al., 2008). Today, catfish occupy an important position as a fish stock in the coastal areas of Indo-Pacific regions (Menon, 2003). The otolith analyzed in this study was obtained from a catfish (order Siluirofrmes) in the family Arridae. Their otoliths are characteristically large, often as much as 1 cm long (Chen et al., 2011; Dan, 1980), and hence are well suited to provide high-resolution ecological and climatological data. We analyzed d 18 O and element/Ca ratios in the same otolith of a catfish collected off the coast of western India to estimate its migration history and to assess the potential of this analysis to be used as an environmental recorder. MATERIALS AND METHODS Climatology of Gujarat The study region is located in the Gujarat state in western India (Fig. 1). Gujarat is a large peninsula lying

Bomb‐14C Peak in the North Pacific Recorded in Long‐Lived Bivalve Shells (Mercenaria stimpsoni)

“…After photographs of the cross sections were taken, we obtained samples for 14 C analysis by drilling the outer shell layer (Kubota et al, 2017), using a high-precision micromilling system (Geomill326, Izumo Web, Japan) with a triangle-shaped tungsten carbide drill bit (Shofu) (e.g., Kubota et al, 2015;Sakamoto et al, 2017). The drilling path was centered on a relatively wide annual growth increment, with a length of 10 mm, width of 0.8 mm, and depth of 1.4 mm, thus producing 10-15 mg of calcium carbonate powder (Figures 2b and 2c).…”

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

“…The determined average δ 13 C value for translucent grains of IAEA-603 was +2.46 ± 0.04 ‰, and that for white opaque grains was +2.33 ± 0.08 ‰; the average δ 18 Both the δ 13 C and the δ 18 O values differed significantly between translucent and white opaque grains (P < 0.001). IAEA-CO-1, which was also prepared from the same marble material as IAEA-603, has highly homogeneous δ 13 ( Figure 4A). According to the IAEA-603 reference sheet, 9 storage in sealed ampules helps prevent the exchange of moisture and CO 2 between the sample and the atmosphere.…”

“…9 The development of advanced high-precision micromilling systems (e.g., New Wave/Merchantek MicroMill ® ; 10 Izumo-web/ GEOMILL326 11 ) has made it possible to obtain very small (submicrogram) samples of carbonate, and the isotopic compositions of small (<100 μg) samples of biogenic carbonate such as fish otoliths and molluscs can be used for high-resolution reconstruction of paleoenvironments. [12][13][14][15] In addition, the isotopic compositions of single microfossil specimens, such as foraminiferal tests (<50 μg), are being used as new environmental and paleoecological proxies. [16][17][18][19][20] To ensure the reliability of microscale isotopic analyses of carbonate, grain-scale δ 13 C and δ 18 O variations in the IAEA-603 new international reference material must be examined.…”

Isotopic analysis of otolith carbonates using laser heating: A fast method for obtaining high‐resolution climate signal

“…The isotopic enrichment effect of removing the organic matter, consisting mostly of carbon compounds, is expected to be more in the δ 13 C values than in the δ 18 O values, which is consistent with our finding. In summary, our results show that the roasting did not cause any significant change in the δ 18 O values but it enriched the 13 C values. In this context, we must acknowledge that complete removal of the binding organic matter associated with the otolith carbonate minerals is never possible, and by roasting we could only lower the organic matter contribution to the isotopic values.…”