Antarctic Krill Under Sea Ice: Elevated Abundance in a Narrow Band Just South of Ice Edge

Brierley, Andrew S.; Fernandes, Paul G.; Brandon, Mark A.; Armstrong, Frederick H.; Millard, N.W.; McPhail, S.D.; Stevenson, Peter; Pebody, Miles; Perrett, James; Squires, Mark; Bone, Douglas G.; Griffiths, Gwyn

doi:10.1126/science.1068574

Cited by 251 publications

(134 citation statements)

References 19 publications

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“…Antarctic krill may be found at high concentrations near the ice edge in winter (Marschall 1988;Tynan 1998;Nicol et al 2000). Further, krill have also been located under winter sea ice (Marschall 1988;Daly and Macaulay 1991), with the highest concentrations found within 200 km of the outer edge of the pack (Daly and Macaulay 1991;Brierley et al 2002). As such, it is plausible that the high concentration of prey in the outer edge of the pack would explain the penguins' preference for this zone.…”

Section: Discussionmentioning

confidence: 99%

Post-breeding dispersal of Adélie penguins (Pygoscelis adeliae) nesting at Signy Island, South Orkney Islands

2010

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ARGOS satellite telemetry and Global Location Sensors (geolocators) were used to identify the moult locations and the winter foraging dispersal of Adélie penguins after they left their breeding colonies on Signy Island in the South Orkney Islands. Animals were tracked during the period December 2004 to October 2005. All birds displayed a similar pattern of migratory behaviour, remaining away from colonies for approximately 9 months, at distances of up to 2,235 km. Moult locations were within the pack ice. Mean daily travel speeds to the moult locations were significantly faster when moving through open water than through pack ice. Moult occurred during February/March within a narrow latitudinal range (65-71°S), at a mean distance of 126 km from the ice edge; the mean duration of individual moult was c. 18.6 days. After moult, penguins spent the subsequent winter months moving north or north-eastward within the expanding winter pack ice, at a mean distance of 216 km from the ice edge, and in areas with ice cover [80%. The penguins returned to the vicinity of their colony between September 26 and October 22, 2005. This dependence of Adélie penguins on sea ice habitat suggests that any further reductions in sea ice extent in the Weddell Sea region would potentially have important impacts on the population processes of this pagophilic species.

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Section: Discussionmentioning

confidence: 99%

Post-breeding dispersal of Adélie penguins (Pygoscelis adeliae) nesting at Signy Island, South Orkney Islands

2010

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“…Moreover, acoustic surveys determined large aggregation of krill under the ice during summer (e.g. Brierley and Watkins 2000;Brierley et al 2002). The role of sea ice for adult krill during the course of the year can be summarised as follows.…”

Section: Body Lipid and Protein Utilisationmentioning

confidence: 99%

The overwintering of Antarctic krill, Euphausia superba, from an ecophysiological perspective

2011

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A major aim of this review is to determine which physiological functions are adopted by adults and larvae to survive the winter season with low food supply and their relative importance. A second aim is to clarify the extent to which seasonal variation in larval and adult krill physiology is mediated by environmental factors with a strong seasonality, such as food supply or day light. Experimental studies on adult krill have demonstrated that speciWc physiological adaptations during autumn and winter, such as reduced metabolic rates and feeding activity, are not caused simply by the scarcity of food, as was previously assumed. These adaptations appear to be inXuenced by the local light regime. The physiological functions that larval krill adopt during winter (reduced metabolism, delayed development, lipid utilisation, and variable growth rates) are, in contrast to the adults, under direct control by the available food supply. During winter, the adults often seem to have little association with sea ice (at least until early spring). The larvae, however, feed within sea ice but mainly on the grazers of the ice algal community rather than on the algae themselves. In this respect, a miss-match in timing of the occurrence of the last phytoplankton blooms in autumn and the start of the sea ice formation, as has been increasingly observed in the west Antarctic Peninsula (WAP) region, will impact larval krill development during winter in terms of food supply and consequently the krill stock in this region.

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“…Many explanations for the circumpolar distribution of krill have been proposed, including sea ice (Mackintosh 1973, Brierley et al 2002, gyres (Marr 1962, Pakhomov 2000, Nicol 2006, fronts (Spiridonov 1996, Witek et al 1988, Tynan 1998, shelf edges (Siegel 2005, Nicol 2006) and high food concentrations (Constable et al 2003, Atkinson et al 2004). However, none of these fully accounts for the distribution patterns, as exceptions apply to each.…”

Section: Top-down and Bottom-up Controls On Krill Ecologymentioning

confidence: 99%

Oceanic circumpolar habitats of Antarctic krill

Atkinson

Siegel²,

Pakhomov³

et al. 2008

Mar. Ecol. Prog. Ser.

340

316

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Antarctic Krill Under Sea Ice: Elevated Abundance in a Narrow Band Just South of Ice Edge

Cited by 251 publications

References 19 publications

Post-breeding dispersal of Adélie penguins (Pygoscelis adeliae) nesting at Signy Island, South Orkney Islands

Post-breeding dispersal of Adélie penguins (Pygoscelis adeliae) nesting at Signy Island, South Orkney Islands

The overwintering of Antarctic krill, Euphausia superba, from an ecophysiological perspective

Oceanic circumpolar habitats of Antarctic krill

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