Seasonality of the Physical and Biogeochemical Hydrography in the Inflow to the Arctic Ocean Through Fram Strait

Eastern Fram Strait and the shelf slope region north of Svalbard is dominated by the advection of warm, salty and nutrient-rich Atlantic Water (AW). This oceanic heat contributes to keeping the area relatively free of ice. The last years have seen a dramatic decrease in regional sea ice extent, whic...

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Bibliographic Details
Published in:Frontiers in Marine Science
Main Authors: Achim Randelhoff, Marit Reigstad, Melissa Chierici, Arild Sundfjord, Vladimir Ivanov, Mattias Cape, Maria Vernet, Jean-Éric Tremblay, Gunnar Bratbak, Svein Kristiansen
Format: Article in Journal/Newspaper
Language:English
Published: Frontiers Media S.A. 2018
Subjects:
Arctic Ocean
Atlantic water
hydrography
shelf slope
nutrients
carbon
Science
Q
General. Including nature conservation
geographical distribution
QH1-199.5
Arctic
Round Point
Svalbard
Fram Strait
Sea ice
Online Access:https://doi.org/10.3389/fmars.2018.00224
https://doaj.org/article/f574953d2fd34e28934ef9535d658fa1
Description
Summary:Eastern Fram Strait and the shelf slope region north of Svalbard is dominated by the advection of warm, salty and nutrient-rich Atlantic Water (AW). This oceanic heat contributes to keeping the area relatively free of ice. The last years have seen a dramatic decrease in regional sea ice extent, which is expected to drive large increases in pelagic primary production and thereby changes in marine ecology and nutrient cycling. In a concerted effort, we conducted five cruises to the area in winter, spring, summer and fall of 2014, in order to understand the physical and biogeochemical controls of carbon cycling, for the first time from a year-round point of view. We document (1) the offshore location of the wintertime front between salty AW and fresher Surface Water in the ocean surface, (2) thermal convection of Atlantic Water over the shelf slope, likely enhancing vertical nutrient fluxes, and (3) the importance of ice melt derived upper ocean stratification for the spring bloom timing. Our findings strongly confirm the hypothesis that this “Atlantification,” as it has been called, of the shelf slope area north of Svalbard resulting from the advection of AW alleviates both nutrient and light limitations at the same time, leading to increased pelagic primary productivity in this region.

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