Potential Trophic Transfer Research Articles

Influence of body length, life-history status and sex on trace metal concentrations in selected zooplankton collectives from the Greenland Sea

An important pre-condition for using aquatic invertebrates as biomonitors is a quantification of their biological attributes or life-history traits on trace metal levels accumulated under field conditions. In the present study we report data obtained for the amphipods Themisto libellula and T. abyssorum and the copepod Calanus hyperboreus from the Greenland Sea. Regarding T. libellula we obtained exponential relationships between Cd, Pb, Cu and Ni concentrations and their body length, while for Zn no length dependency was noted. Further, substantial differences between juveniles from the marsupium versus adults were recorded for both amphipod collectives investigated (0.06–0.21 vs 26–50 mg Cd kg −1 dry wt and 3 vs 26–37 mg Cu kg −1). Significant differences were also noted for copepods, with juveniles showing, for example, somewhat enhanced Cd levels, but they were not as pronounced as those for amphipods (0.54–0.67 vs 0.94 mg Cd kg −1). Results are discussed focussing on potential for trophic transfer and on metabolic requirements. Finally, we recommend utilization of only adult individuals in routine biomonitoring studies.

Trophic transfer and biomagnification potential of contaminants in aquatic ecosystems.

This review summarizes information obtained from published literature to determine to what degree biomagnification of organic compounds and metals occurs in freshwater and marine food webs. This review was conducted by: (1) examining data from studies conducted in laboratory experiments to establish body burden ratios between trophic levels (trophic transfer coefficients; TTCs); (2) comparing laboratory-derived TTCs with data obtained from field studies; and (3) comparing biomagnification predictions described by published aquatic food-web models with data obtained in this review. It was determined that: (1) the majority of chemicals evaluated (both organic and metals) do not biomagnify in aquatic food webs; (2) for many of the compounds examined, considerable trophic transfer does occur in aquatic food webs; (3) DDT, DDE, PCBs, toxaphene, methyl mercury, total mercury, and arsenic have the potential to biomagnify in aquatic systems; (4) the lipid fraction of receptors directly influences biomagnification of lipophilic compounds; (5) the food web model reviewed provided similar estimates for most of the organic compounds examined (log Kow values between 5 and 7), with model predictions falling within the range of values of all compounds except dieldrin; (6) for many organic compounds, lack of information precludes assessing the relative importance of biomagnification for these contaminants; and (7) even those compounds for which evidence for biomagnification is strongest show considerable variability and uncertainty regarding the magnitude and existence of food-web biomagnification in aquatic systems.