Significance and interspecific variability of accumulated trace metal concentrations in Antarctic benthic crustaceans

Trace metals (Cd, Cu, Pb and Zn) were analysed in crustaceans collected on Polarstern cruises ANT XVI/2 (1999) and ANT XXI/2 (2003/04, BENDEX) to the Weddell Sea. Our study provides further evidence for the frequently reported "Cd anomaly" in polar crustaceans, with data ranging from 1.2 (Ceratoserolis trilobitoides) to 6.2 mg Cd kg-1 DW (Notocrangon antarcticus) in 1999 and from 1.2 (Waldeckia obesa) to 20.3 mg Cd kg-1 (Tryphosella murrayi) in 2003. Pb concentrations well below 1 mg kg-1 in most of the samples analysed might serve as a regional or even global background value for comparison in biomonitoring studies. Increasing Cu concentrations from eggs of decapods (e.g., 5 vs. 51 mg kg-1 in N. antarcticus) or juveniles in the brood pouch of an amphipod species to adult females indicate that the enzymatic requirements and haemocyanin component demand for Cu in early life-history stages is probably not met without a distinct bioaccumulation of this essential element after hatching. Most interestingly, Cd also increases (-1 in N. antarcticus). This could be the consequence of efficient uptake mechanisms for Cu that cannot discriminate between this element and Cd. Cu and Zn concentrations in decapods of this study are largely within the range reported worldwide (40-90 mg Cu kg-1 and 40-80 mg Zn kg-1), indicating that these elements are regulated. The enormous heterogeneity of Cd and Zn in many amphipod species investigated (e.g., from 0.6 in Gnathiphimedia mandibularis to 34.4 mg Cd kg-1 in Orchomenopsis acanthura and from 41 in Eusirus antarcticus to 1244 mg Zn kg-1 in Iphimediella bransfieldi) supports the hypothesis of the "Cd anomaly" and suggests that there is probably no consistent metabolic demand for the essential element Zn in this taxonomic group. The heterogeneity of Cu in amphipods is less pronounced