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Titel |
Halocline water modification and along-slope advection at the Laptev Sea continental margin |
VerfasserIn |
D. Bauch, S. Torres-Valdes, I. Polyakov, A. Novikhin, I. Dmitrenko, J. McKay, A. Mix |
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 ; 10, no. 1 ; Nr. 10, no. 1 (2014-02-25), S.141-154 |
Datensatznummer |
250116929
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Publikation (Nr.) |
copernicus.org/os-10-141-2014.pdf |
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Zusammenfassung |
A general pattern in water mass distribution and potential shelf–basin
exchange is revealed at the Laptev Sea continental slope based on
hydrochemical and stable oxygen isotope data from the summers 2005–2009. Despite
considerable interannual variations, a frontal system can be inferred
between shelf, continental slope and central Eurasian Basin waters in the
upper 100 m of the water column along the continental slope. Net sea-ice
melt is consistently found at the continental slope. However, the sea-ice
meltwater signal is independent from the local retreat of the ice cover and
appears to be advected from upwind locations.
In addition to the along-slope frontal system at the continental shelf
break, a strong gradient is identified on the Laptev Sea shelf between
122° E and 126° E with an eastward increase of riverine
and sea-ice related brine water contents. These waters cross the shelf break
at ~ 140° E and feed the low-salinity halocline
water (LSHW, salinity S < 33) in the upper 50 m of the water column.
High silicate concentrations in Laptev Sea bottom waters may lead to
speculation about a link to the local silicate maximum found within the
salinity range of ~ 33 to 34.5, typical for the Lower Halocline Water (LHW) at the continental slope. However brine signatures and
nutrient ratios from the central Laptev Sea differ from those observed at
the continental slope. Thus a significant contribution of Laptev Sea bottom
waters to the LHW at the continental slope can be excluded. The silicate
maximum within the LHW at the continental slope may be formed locally or at
the outer Laptev Sea shelf. Similar to the advection of the sea-ice melt
signal along the Laptev Sea continental slope, the nutrient signal at 50–70 m
water depth within the LHW might also be fed by advection parallel to the
slope. Thus, our analyses suggest that advective processes from upstream
locations play a significant role in the halocline formation in the northern
Laptev Sea. |
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