MEPS 563:13-23 (2017)  -  DOI: https://doi.org/10.3354/meps11978

Marine micronutrient vectors: seabirds, marine mammals and fishes egest high concentrations of bioactive metals in the subantarctic island ecosystem

S. R. Wing1,*, L. C. Wing1, O. A. Shatova1, R. Van Hale2

1Department of Marine Science and 2Department of Chemistry, University of Otago, PO Box 56, Dunedin 9054, New Zealand
*Corresponding author:

ABSTRACT: We investigated concentrations of bioactive metals (Mn, Fe, Co, Ni, Cu, Zn, As, Cd) in organic matter source pools: suspended particulate organic matter and macroalgae, and macrozooplankton from the vicinity of the Snares Islands, situated adjacent to the Subtropical Frontal Zone south of New Zealand. Further we sampled egested material from 6 coastal fishes, 8 seabirds and 2 pinniped species with rookeries on the islands. Analysis of δ15N and δ13C from basal organic matter sources, zooplankton, fish muscle tissue and egesta of fishes, seabirds and pinnipeds was used to estimate trophic position for each group. We found a food web heavily dependent on pelagic productivity culminating with New Zealand fur seals and Hooker’s sea lions. We compared multivariate concentration profiles of metals in the egesta of 4 trophic level groups from the Snares Islands with 4 similar trophic groups from the Auckland Islands. Results indicated more variation in concentration of bioactive metals in egesta among trophic level groups, than among islands. These results demonstrated that several potentially limiting micronutrients (Mn, Fe, Co, Zn) are bioaccumulated in the egesta of upper trophic levels of subantarctic food webs. The variance in concentration patterns of bioactive metals is more coincident with differences in food web structure than differences in water mass type surrounding the 2 islands. The patterns observed have important implications for understanding the interactions between food web architecture, biological vectors and productivity around the subantarctic islands of the Southern Ocean.


KEY WORDS: Southern Ocean · Iron · Seabird · Fish · Marine mammal · Nutrient vector


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Cite this article as: Wing SR, Wing LC, Shatova OA, Van Hale R (2017) Marine micronutrient vectors: seabirds, marine mammals and fishes egest high concentrations of bioactive metals in the subantarctic island ecosystem. Mar Ecol Prog Ser 563:13-23. https://doi.org/10.3354/meps11978

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