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Marine Ecology Progress Series

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Adélie penguins returning from foraging; and the glider at Cape Crozier, Ross Island—nose down, antenna up—poised to begin quantification of penguin food. Photos: D. Ainley and W. Smith

Ainley DG, Ballard G, Jones RM, Jongsomjit D, Pierce SD, Smith WO Jr, Veloz S


Trophic cascades in the western Ross Sea, Antarctica: revisited



Marine food webs are structured by top-down (predation) and bottom-up (production) forces, but assessments of the effects of predation in open-water systems are difficult and rare. Ainley and co-authors used an acoustically equipped autonomous glider, satellite-linked time-depth recorders on Adélie penguins and censuses of co-foraging cetaceans in the Ross Sea, Antarctica, to assess changes in the preyscape and environment, as well as foraging pressure and changes in availability of crystal krill and silverfish, the two main prey species of penguins and whales. Simultaneously the glider also assessed food availability for the prey species, using chlorophyll concentration as a proxy. In this wasp-waist food web, prey depth and abundance were uncoupled from their food, but were strongly altered by temporal changes in predation pressure.


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