Utility of Nd isotope ratio as a tracer of marine animals: regional variation in coastal seas and causal factors

Abstract

2018. Utility of Nd isotope ratio as a tracer of marine animals: regional variation in coastal seas and causal factors. Ecosphere 9(8):Abstract. Isotopic compositions of animal tissue are an intrinsic marker commonly used to trace animal origins and migrations; however, few isotopes are effective for this purpose in marine environments, especially on a local scale. The isotope ratio of the lanthanoid element neodymium (Nd) is a promising tracer for coastal animal migrations. Neodymium derives from the same geologic materials as strontium, well known as an isotopic tracer ( 87 Sr/ 86 Sr) for terrestrial and anadromous animals. The advantage of the Nd isotope ratio ( 143 Nd/ 144 Nd, expressed as e Nd ) is that it varies greatly in the ocean according to the geology of the neighboring continents, whereas oceanic 87 Sr/ 86 Sr is highly uniform. This study explored the utility of the Nd isotope ratio as a marine tracer by investigating the variation of e Nd preserved in tissues of coastal species, and the causes of that variation, in a region of northeastern Japan where the bedrock geology is highly variable. We measured e Nd and 87 Sr/ 86 Sr in seawater, river water, and soft tissues of sedentary suspension feeders: the mussels Mytilus galloprovincialis and Mytilus coruscus and the oyster Crassostrea gigas. We also measured concentrations of three lanthanoids (La, Ce, and Pr) in shellfish bodies to determine whether the Nd in shellfish tissue was derived from solution in seawater or from suspended particulates. The e Nd values in shellfish tissue varied regionally (À6 to +1), matching the ambient seawater, whereas all 87 Sr/ 86 Sr values were homogeneous and typical of seawater (0.7091-0.7092). The seawater e Nd values were in turn correlated with those in the adjacent rivers, linking shellfish e Nd to the geology of river catchments. The depletion of Ce compared to La and Pr (negative Ce anomaly) suggested that the Nd in shellfish was derived from the dissolved phase in seawater. Our results indicate that the distinct Nd isotope ratio derived from local geology is imprinted, through seawater, on the soft tissues of shellfish. This result underscores the potential of e Nd as a tracer of coastal marine animals.

The universal imprint of oxygen isotopes can track the origins of seafood

“…By contrast, neodymium isotopes ( 143 Nd/ 144 Nd ratios expressed as Ɛ Nd values) are indicated to be governed by continental geology, resulting in distinct geographic ocean profiles with high spatial resolution (Jeandel et al, 2007). Recent research demonstrated that Ɛ Nd values in the soft and hard tissues of bivalve molluscs are highly effective at identifying the origins of individuals at even small spatial scales (10s km) (Saitoh et al, 2018; Tanaka et al, 2022; Zhao et al, 2019). Concentrations of barium ratioed to calcium (Ba/Ca) are an additional candidate for universal provenance, as signatures reflect seawater composition (Bath et al, 2000; Walther & Thorrold, 2006), and are little affected by individual life history factors, such as physiology or diet (Grammer et al, 2017; Hüssy et al, 2021; Martino et al, 2021).…”

Tracking long‐distance migration of marine fishes using compound‐specific stable isotope analysis of amino acids

“…One advantage of the isotope tracking method is that it can reveal migration routes of individual animals over a prolonged timescale (the timescale of bone growth). Although the spatial resolution of the method depends on the spatial scale of isotopic gradients among habitats, the use of additional isoscapes based on radiocarbon content (Larsen et al 2018) or neodymium stable isotope ratios (Saitoh et al 2018) could help enable finer‐scale determinations of fish migration routes.…”

Designing Porous Ion Emitters for Thermal Ionization Mass Spectrometry: Evaluating Metal–Organic Frameworks

“…Here, we focus on neodymium (Nd), which is becoming widely applied to many areas outside of traditional geochemistry and geochronology. Recent applications include paleoceanography, nuclear forensics, and source attribution with each new application necessitating the analysis of smaller sample sizes. − For example, isotope ratios of neodymium ( 143 Nd/ 144 Nd) extracted from marine animal samples have been used as intrinsic markers of local geology to track their origin …”

“…1−3 For example, isotope ratios of neodymium ( 143 Nd/ 144 Nd) extracted from marine animal samples have been used as intrinsic markers of local geology to track their origin. 4 While multicollector inductively coupled plasma mass spectrometry has become popular for such sensitive measurements, the overall efficiency (number of atoms analyzed relative to the number of atoms available) of these systems is 1−2%. 5,6 By contrast, the efficiency of thermal ionization mass spectrometry (TIMS) measurements varies with the analyte of interest, quality of sample preparation, and loading technique.…”