Differential bioaccumulation behaviour of Ag and Cd during the early development of the cuttlefish Sepia officinalis

Abstract

Ag activity continued to increase in eggs, whereas 109 Cd kinetics displayed a significant decrease. Whatever the development stage, Cd was mainly associated with the eggshell all along the exposure experiment. In addition, both stable Cd concentrations and 109 Cd LCR remained low in the embryo all along the embryonic development, indicating that the eggshell acted as an efficient shield against the penetration of this metal. In contrast, 110mAg passed through the eggshell from day 30 onwards and was then accumulated in the embryo, which contained more than 40% of the whole egg metal burden at the end of the exposure period. In depuration conditions, it is noteworthy that Ag continued to accumulate in the embryo indicating translocation processes from the eggshell and a high affinity of the metal for the embryo tissues. Overall our results showed that at day 30 of the embryonic development the cuttlefish eggshell becomes permeable to Ag but not to Cd.Exposure to stable metals confirmed the saturation capacities of the eggshell for Cd and the Ag penetration properties.

Elemental uptake via immersion: a mass-marking technique for the early life-history stages of ­cephalopods

“…The timing of organogenesis for cephalopods is highly species-and temperaturedependent (Boletzky 1983), but is completed by day 32 of the 50 d development period for S. officinalis (Lacoue-Labarthe et al 2009), and a similar timing of organogenesis for S. apama could explain why 137 Ba was not assimilated until the second half of the development period. S. officinalis embryos exposed to elevated levels of a range of metals (Ag, Co, Cs, Mn and Zn) have also been shown to accumulate them in tissues only during the latter 40% of development, with the second half of development being associated with an increased permeability of the egg capsule to these metals (Lacoue-Labarthe et al 2008. Similarly, the oxygen conductance of S. apama egg capsules increases gradually in the first half of development, but rapidly in the last 30 to 40% of the development period (Cronin & Seymour 2000).…”

Effects of increased <i>p</i>CO<sub>2</sub> and temperature on trace element (Ag, Cd and Zn) bioaccumulation in the eggs of the common cuttlefish, <i>Sepia officinalis</i>

“…During the embryonic development of cuttlefish, the greatest amounts of the metals, such as Ag, 241 Am, Cd, Co, Hg, Mn, Pb and Zn, remain associated with the eggshell (Bustamante et al, 2002(Bustamante et al, , 2004Lacoue-Labarthe et al 2008a, 2009a. Indeed, the eggshell contains a high proportion of mucin proteins that also have a high content of sulfydrilgroups (Boletzky, 1986) for which Ag, Cd and Zn have a high affinity (e.g., Wedemeyer, 1968;Temara et al, 1997;Bell and Kramer, 1999).…”

“…Uptake of 110m Ag, 109 Cd and 65 Zn in the vitellus and the embryo during the development time were expressed as changes in total activity/concentration ratio (Load concentration ratio; LCR; g; ratio between radiotracer content in the vitellus or the embryo -Bq -and time-integrated activity in seawater -Bq g −1 ) over time (Lacoue-Labarthe et al, 2008a). Although this ratio is a rather unusual way to express metal accumulation, whole radioactivity content in the vitellus and the embryo was preferred over the concentration factor in order to overcome the problem of dramatic weight variations of these egg compartments that tends to mask the actual accumulation of metals in the whole egg.…”

“…Exposed to various dissolved trace elements, the cuttlefish eggshell is likely to act as a protective barrier that limits or hinders the incorporation of metals into the embryo during the first developmental stages, with a permeability that is element-specific (Bustamante 2002(Bustamante , 2004Lacoue-Labarthe 2008a). The subsequent incorporation of water into the perivitelline fluid as the egg swells appears to be a key process in metal penetration.…”

“…The subsequent incorporation of water into the perivitelline fluid as the egg swells appears to be a key process in metal penetration. Thus, we hypothesized that, in coastal shallow waters, ocean acidification and warming could affect embryonic metabolism and the shielding properties of the eggshell components, and could lead to shifts in a) the accumulation of essential element (Zn) and b) the capacity of the eggshell to protect against the penetration of non-essential or toxic elements, such as Ag and Cd, known for their contrasting uptake behaviours (Lacoue-Labarthe et al, 2008a). These three trace elements are known to be very toxic to early development stages of marine invertebrate (Calabrese et al, 1974).…”