The effects of temperature and water concentration on the otolith incorporation of barium and manganese in black rockfish Sebastes melanops

Abstract

Observations of multiple years of geographic variation in [Ba:Ca](otolith) and [Mn:Ca](otolith) in black rockfish Sebastes melanops prompted this study to examine the effects of temperature and water concentration on the otolith incorporation of Ba and Mn in this wholly marine species. The replicated experiment design consisted of two water temperatures (7.4 and 13.0 degrees C) and four water concentrations of Ba:Ca and Mn:Ca. A positive, linear relationship between [Ba:Ca](water) and [Ba:Ca](otolith) was observed at both temperatures. A positive temperature effect was also observed with mean partition coefficients for Ba (D(Ba)) greater in the 13 degrees C than in the 7.4 degrees C treatments (mean = 0.061 and 0.048, respectively). There was no relationship between [Mn:Ca](water) and [Mn:Ca](otolith) although a negative temperature effect was observed. Mean partition coefficients for Mn (D(Mn)) were lower in the 13 degrees C than in the 7.4 degrees C treatments (mean = 0.027 and 0.036, respectively). The data presented support the assumption of a positive, linear relationship between water and otolith Metal:Ca concentrations for Ba:Ca but not for Mn:Ca. Thus, although indicative of residence in distinct water masses, observed variation in [Metal:Ca](otolith) may not reflect variation in water concentration and can be affected by temperature. Caution should be applied in the interpretation of geographic variation of [Mn:Ca](otolith) until the mechanisms regulating its incorporation are more fully understood.

Evaluating chemical signatures in a coastal upwelling region to reconstruct water mass associations of settlement-stage rockfishes

“…Our results are consistent with previous research indicating that species-specific temperature effects can influence partition coefficients for metals such as Ba and Mg, confirming the need for validation studies prior to interpreting values in wild-caught fish (Elsdon & Gillanders 2002, Bath Martin et al 2004, Miller 2009, 2011. Our observation that there was no temperature effect on D Sr for either species contrasts with the behavior of the Sr/Ca ratio in biogenic aragonite in different taxa observed by others (Shen et al 1996, Elsdon & Gillanders 2002, Zacherl et al 2003, Bath Martin et al 2004), which may be explained by the magnitude and relatively narrow temperature range tested in our study.…”

“…Reduced ability to discriminate against Ba during entry into the endolymph has been postulated to occur at lower temperatures for juveniles of the black bream Acanthopagrus butcheri (Elsdon & Gillanders 2002; however, species may differ in their responses to temperature, because the related physiological processes are likely species-specific (Bath et al 2000, Elsdon & Gillanders 2003. Miller (2009) found lower D Ba values at 7.4°C than at 13°C in the black rockfish S. melanops, which may be a consequence of differences in seawater concentrations or experimental conditions. The range of D Ba measured by Miller (2009), however, spans a similar range to that measured in this study.…”

“…In general, some elements are incorporated into otoliths in proportion to ambient environmental concentrations (Campana & Thorrold 2001, Elsdon et al 2008. However, diet, temperature and salinity can influence the incorporation of elements into otoliths, and these effects may be species or life-stage specific (Elsdon & Gillanders 2002, Bath Martin et al 2004, Elsdon et al 2008, Miller 2009, 2011, Walther et al 2010. The effect of temperature on otolith chemistry is especially important to consider in marine systems because temperature may vary by as much as 9ºC, unlike salinity, which exhibits minimal variation.…”

Resiliency of juvenile walleye pollock to projected levels of ocean acidification

“…Normalized ion ratios (e.g. Mg:Ca) were converted to concentration based on measurements of National Institute of Standards and Technology (NIST) 612 standard glass and are presented as molar ratios (Miller 2009 We collected data on water chemistry to confirm that elemental concentrations of rearing waters were not altered by the process of CO 2 level manipulation and to calculate elemental partition coefficients to more accurately determine whether there were de tectable changes in the rates of elemental incorporation among CO 2 treatments (Morse & Bender 1990). Weekly water samples were collected from each CO 2 treatment throughout the experiment.…”

Estimating behavior in a black box: how coastal oceanographic dynamics influence yearling Chinook salmon marine growth and migration behaviors

“…Sagittal otoliths were removed, cleaned, and polished using wet-or-dry paper (240-2500 grit) and lapping film (1-30 µm) using standard procedures for elemental analysis (Miller 2009). Otolith Sr and Ca were measured along the dorsal-ventral growth axis using laser ablation-inductively coupled plasma mass spectrometry.…”