Journal cover Journal topic
Ocean Science An interactive open-access journal of the European Geosciences Union
Ocean Sci., 10, 141-154, 2014
https://doi.org/10.5194/os-10-141-2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
25 Feb 2014
Halocline water modification and along-slope advection at the Laptev Sea continental margin
D. Bauch1, S. Torres-Valdes2, I. Polyakov3, A. Novikhin4, I. Dmitrenko5, J. McKay6, and A. Mix6 1GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1–3, 24148 Kiel, Germany
2Ocean Biogeochemistry and Ecosystems, National Oceanography Centre (NOC), European Way, Southampton, SO14 3ZH, UK
3International Arctic Research Center and College of Natural Science and Mathematics, University of Alaska Fairbanks, Fairbanks, Alaska, USA
4Arctic and Antarctic Research Institute, St. Petersburg, Russia
5Centre for Earth Observation Science, University of Manitoba, Winnipeg, Manitoba, Canada
6College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, USA
Abstract. 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.


Citation: Bauch, D., Torres-Valdes, S., Polyakov, I., Novikhin, A., Dmitrenko, I., McKay, J., and Mix, A.: Halocline water modification and along-slope advection at the Laptev Sea continental margin, Ocean Sci., 10, 141-154, https://doi.org/10.5194/os-10-141-2014, 2014.
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