Water, not food, contributes the majority of strontium and barium deposited in the otoliths of a marine fish

Abstract

We quantified the relative contributions of water and food to strontium (Sr) and barium (Ba) Ba ratios in otoliths were quantified using laser ablation ICP-MS. The relative contributions of water and food sources to otolith aragonite were assessed using a simple linear isotope mixing model. Water sources contributed 83% of Sr and 98% of Ba in otoliths formed in spiked seawater. Our results indicate that water chemistry is the dominant factor controlling the uptake of Sr and Ba in the otoliths of marine fishes. Thus, chemical signatures recorded in the otoliths of marine fishes should reflect the ambient water composition of these elements at the time of deposition. KEY WORDS: Otolith · Element uptake · Sr isotope · Ba isotope · Water sources Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 311: [125][126][127][128][129][130] 2006 water and diet is important because we would only expect otolith chemistry to reflect dissolved concentrations in the environment if water were the primary source of ions in the otoliths.Traditionally, water was thought to contribute most to the composition of calcareous structures in teleosts (Schiffman 1961, Berg 1968, Simkiss 1974, Hoff & Fuiman 1995, Farrell & Campana 1996, Gallahar & Kingsford 1996. However, dietary composition may also influence otolith chemistry. The elemental composition of otoliths has been shown to reflect diet in both freshwater (Limburg 1995, Kennedy et al. 2000 and marine (Buckel et al. 2004) fishes. We sought to address these discrepancies by rearing juvenile mummichogs Fundulus heteroclitus in seawater spiked with enriched Sr and Ba isotopes beyond the natural isotope ratios found in food. This experimental approach provided a definitive test of the relative contributions of water and diet to otolith composition. MATERIALS AND METHODSFish-rearing conditions. Mummichogs are estuarine killifish that occupy marsh habitats along the east coast of North America from Florida to Newfoundland (Collette & Klein-MacPhee 2002). Individuals were collected from Eel Pond in Woods Hole, Massachusetts, using baited minnow traps set during spring tides in June 2002. Eggs were manually extracted from gravid females and fertilized in vitro by commingling eggs and diced testes from sacrificed males in Petri dishes containing filtered natural seawater. The pieces of testes were removed after 24 h. Eggs developed in Petri dishes at a room temperature of 19°C and seawater was changed every 3 d. Eggs hatched after approximately 28 d and the larvae were then transferred to experimental tanks.High-density polyethylene tanks were filled with 10 l filtered natural seawater at a salinity of 30 (PSU). Replicate control tanks contained unaltered seawater, while treatment tanks were spiked with 1 mg 86 Sr and 50 μg 137 Ba each. Stable isotopes were purchased from Oak Ridge National Laboratory, Tennessee, USA. After treatment tanks were spiked, 10 fish were added to each tank, except for 1 control tank that contained only 9 fi...

Do vertebral chemical signatures distinguish juvenile blacktip shark (Carcharhinus limbatus) nursery regions in the northern Gulf of Mexico?

“…Under estuarine conditions, bony fish otolith Sr : Ca generally shows a positive correlation with salinity, whereas Ba : Ca typically shows a negative relationship with salinity (Limburg 1995;Elsdon and Gillanders 2005;Macdonald and Crook 2010). Because a large portion of otolith Sr and Ba is derived from the surrounding water (Walther and Thorrold 2006;Webb et al 2012;Izzo et al 2015), fluctuations in Sr : Ca and Ba : Ca can be used to infer the relative salinity of environments experienced by a fish during its lifetime (e.g. Limburg 1995).…”

Multi-element otolith fingerprints unravel sea−lagoon lifetime migrations of gilthead sea bream Sparus aurata

“…They are, therefore, natural tags whose structure and chemistry provide a record of the environmental history of individuals throughout their lives (Campana 1999), and can reveal movements of present and ancient fish between different water bodies (e.g. Carpenter et al 2003, Walther & Thorrold 2006, Clarke et al 2009, Tanner et al 2011. Nevertheless, most studies in this field (e.g.…”

Dietary effects on multi-element composition of European eel (Anguilla anguilla) otoliths

“…Previous investigations on the importance of food on element incorporation into otoliths were highly ambiguous. Walther and Thorrold (2006) concluded that Sr and Ba contents in marine Wsh otoliths clearly reXect ambient Sr and Ba concentrations, while Kennedy et al (2000) reported 70% of the Sr isotopic signature in freshwater Atlantic salmon (Salmo salar) otoliths to originate from food. SigniWcant dietary eVects on strontium incorporation have been demonstrated for American shad (Alosa sapidissima) (Limburg 1995) and Black bream (Girella elevata) (Gallahar and Kingsford 1996) and for strontium and barium incorporation in blueWsh (Pomatomus saltatrix) (Buckel et al 2004).…”

“…DiVerent analytical methods are commonly used for microchemical studies of Wsh otoliths: Synchrotron X-ray Xuorescence analysis (Tsukamoto et al 1998), particle induced X-ray emission (PIXE; Elfman et al 1999), electron probe microanalysis (HoV and Fuiman 1995), solution based inductively coupled plasma mass spectrometry (ICP-MS; Buckel et al 2004) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS; Walther and Thorrold 2006). In the present study, LA-ICP-MS was chosen to measure feed-dependency on the incorporation of 16 elements because of its high precision in multi-element analysis and good spatial resolution.…”