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| Titel |
Upper ocean stratification and sea ice growth rates during the summer-fall transition, as revealed by Elephant seal foraging in the Adélie Depression, East Antarctica |
| VerfasserIn |
G. D. Williams, M. Hindell, M.-N. Houssais, T. Tamura, I. C. Field |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1812-0784
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| Digitales Dokument |
URL |
| Erschienen |
In: Ocean Science ; 7, no. 2 ; Nr. 7, no. 2 (2011-03-11), S.185-202 |
| Datensatznummer |
250004534
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| Publikation (Nr.) |
 copernicus.org/os-7-185-2011.pdf |
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| Zusammenfassung |
| Southern elephant seals (Mirounga leonina), fitted with
Conductivity-Temperature-Depth sensors at Macquarie Island in January 2005
and 2010, collected unique oceanographic observations of the Adélie and
George V Land continental shelf (140–148° E) during the
summer-fall transition (late February through April). This is a key region of
dense shelf water formation from enhanced sea ice growth/brine rejection in
the local coastal polynyas. In 2005, two seals occupied the continental shelf
break near the grounded icebergs at the northern end of the Mertz Glacier
Tongue for several weeks from the end of February. One of the seals migrated
west to the Dibble Ice Tongue, apparently utilising the Antarctic Slope Front
current near the continental shelf break. In 2010, immediately after that
year's calving of the Mertz Glacier Tongue, two seals migrated to the same
region but penetrated much further southwest across the Adélie Depression
and sampled the Commonwealth Bay polynya from March through April. Here we
present observations of the regional oceanography during the summer-fall
transition, in particular (i) the zonal distribution of modified Circumpolar
Deep Water exchange across the shelf break, (ii) the upper ocean
stratification across the Adélie Depression, including alongside iceberg
C-28 that calved from the Mertz Glacier and (iii) the convective overturning
of the deep remnant seasonal mixed layer in Commonwealth Bay from sea ice
growth. Heat and freshwater budgets to 200–300 m are used to estimate the
ocean heat content (400→50 MJ m−2), flux
(50–200 W m−2 loss) and sea ice growth rates (maximum of
7.5–12.5 cm day−1). Mean seal-derived sea ice growth rates were
within the range of satellite-derived estimates from 1992–2007 using
ERA-Interim data. We speculate that the continuous foraging by the seals
within Commonwealth Bay during the summer/fall transition was due to
favorable feeding conditions resulting from the convective overturning of the
deep seasonal mixed layer and chlorophyll maximum that is a reported feature
of this location. |
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