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

Seabirds, marine mammals, and fishes around the New Zealand Sub-Antarctic Islands act as critical vectors for bioactive metals (Mn, Fe, Co, Ni, Cu, Zn, As, Cd), concentrating them in their egesta. The study found that upper trophic levels—particularly New Zealand fur seals and Hooker's sea lions—bioaccumulate potentially limiting micronutrients like Mn, Fe, Co, and Zn, with metal concentration patterns more closely tied to food web structure than water mass differences between the Snares and Auckland Islands. Researchers analyzed egested material from 16 species (fishes, seabirds, pinnipeds) alongside suspended particulate organic matter, macroalgae, and zooplankton using isotopic (δ¹⁵N, δ¹³C) and multivariate profiling to assess trophic positions and metal distributions. This highlights the role of biological vectors in nutrient cycling within subantarctic island ecosystems.

Wing, S., Wing, L., Shatova, O., & Van Hale, R. (2017). Marine micronutrient vectors: seabirds, marine mammals and fishes egest high concentrations of bioactive metals in the subantarctic island ecosystem. Marine Ecology Progress Series, 563, 13–23. https://doi.org/10.3354/meps11978