Influence of temperature and salinity on the trace element incorporation into statoliths of the common cuttlefish (Sepia officinalis)

Abstract

The use of statolith chemistry to trace migration pathways and distinguish populations of cephalopods is based on the assumption that the elemental composition of statoliths is influenced by physicochemical properties of the ambient environment. However, such influences have not been investigated experimentally up until now. This study presents the first microchemical analyses of cephalopod statoliths obtained from laboratory experiments under different controlled temperature and salinity conditions. Our results show that statolith chemical composition is strongly related to both salinity and temperature in ambient waters. The Ba/Ca ratio is negatively related to temperature and shows no relation to salinity. The I/Ca ratio is positively related to temperature and negatively to salinity. No Sr/Ca relation was found to either salinity or temperature, suggesting that the well-established proxy strontium is not as useful in cephalopod statoliths as in other biomineralized aragonites. Microanalysis of trace elements, however, shows an enormous potential for field studies on distribution, migration and stock separation of cephalopods. Furthermore, Synchrotron X-ray Fluorescence Analysis is introduced as a promising novel method for statolith analysis, providing a spatial resolution of typically 10-15 lm combined with detection limits down to 0.5 ppm.

Geographic variation in trace-element signatures in the statoliths of near-hatch larvae and recruits of Concholepas concholepas (loco)

“…Using these discriminant functions, only 22% of the recruits were correctly reclassified, which, with few exceptions, lie at the borders of the discriminant function analysis space generated by larvae ratios in the natal core of recruit statoliths collected from the northern region may be interpreted in relation to the presence of a persistent upwelling shadow inside Antofagasta Bay , Lagos et al 2008). This agrees with the significant reduction in Ba/Ca from southern to northern recruit statoliths, and might be associated with the negative effect of temperature in the incorporation of Ba as has been reported in studies conducted in gastropods (Zacherl et al 2003a, Zumholz et al 2007, Lloyd et al 2008 and bivalves (Carson 2010). Interestingly, pre-hatch larval statoliths (where individuals are fixed in place) do not show this pattern, and instead show a significant increase of the Ba/Ca ratio from southern to northern populations.…”

Metapopulation dynamics of the softshell clam, Mya arenaria

“…We found evidence for a negative correlation between temperature and Ba uptake in both larval and juvenile shells, which is consistent with results of Zacherl et al (2003b) and Zumholz et al (2007), who both found a negative correlation in the aragonite structures of laboratory-reared molluscans. We found no significant relationship between DBa and salinity, which is also consistent with results from Zumholz et al (2007).…”

“…We found no significant relationship between DBa and salinity, which is also consistent with results from Zumholz et al (2007). Ba is likely to be a useful addition to elemental tagging studies, even in situations where its concentration does not vary spatially, as uptake into molluscan shell appears to have a consistent relationship with temperature.…”

“…As a result, temperature-associated variation in growth rates or metabolism could have been responsible for the Sr uptake patterns rather than temperature itself. A more recent study of temperature effects on Sr in statoliths of the laboratory-reared cuttlefish Sepia officinalis that controlled for growth rates also reported no correlation, suggesting biological regulation of Sr ions outweighs the kinetic effects of temperature on Sr incorporation (Zumholz et al, 2007 There is less ambiguity in the literature for the relationship between Sr uptake into molluscan calcium carbonate and salinity. The most commonly reported result is a lack of correlation Hallam and Price, 1968;Zumholz et al, 2007), as we found in our larval shells.…”

“…The use of geochemical signatures in fish otoliths as natural tags for population studies is well established ). Recent efforts have expanded the use of elemental tags to invertebrates including decapods (DiBacco and , gastropods (Zacherl et al, 2003a), bivalves , and cephalopods (Arkhipkin et al, 2004;Zumholz et al, 2007).…”