The advective origin of an under-ice spring bloom in the Arctic Ocean using multiple observational platforms

Under-ice blooms of phytoplankton in the Chukchi Sea have been observed, with strong implications for our understanding of the production regimes in the Arctic Ocean. Using a combination of satellite remote sensing of phytoplankton biomass, in situ observations under sea ice from an autonomous under...

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Bibliographic Details
Published in:Polar Biology
Main Authors: Johnsen, Geir, Norli, Marit, Moline, Mark A., Robbins, Ian, Quillfeldt, Cecilie von, Sørensen, Kai, Cottier, Finlo Robert, Berge, Jørgen
Format: Article in Journal/Newspaper
Language:English
Published: Springer Verlag 2018
Subjects:
Arctic
Arctic Ocean
Chukchi Sea
Svalbard
Yermak Plateau
Antarc*
Antarctica
Chukchi
Phytoplankton
Polar Biology
Sea ice
Yermak plateau
Online Access:http://hdl.handle.net/11250/2577917
https://doi.org/10.1007/s00300-018-2278-5
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Summary:Under-ice blooms of phytoplankton in the Chukchi Sea have been observed, with strong implications for our understanding of the production regimes in the Arctic Ocean. Using a combination of satellite remote sensing of phytoplankton biomass, in situ observations under sea ice from an autonomous underwater vehicle (AUV), and in vivo photophysiology, we examined the composition, magnitude and origin of a bloom detected beneath the sea ice Northwest of Svalbard (Southern Yermak Plateau) in May 2010. In situ concentration of up to 20 mg chlorophyll a [Chl a] m− 3, were dominated by the northern planktonic spring species of diatoms, Thalassiosira nordenskioeldii, T. antarctica var. borealis, Chaetoceros socialis species complex and Fragilariopsis oceanica. These species were also found south of the marginal ice zone (MIZ). Cells in the water column under the sea ice were typically high-light acclimated, with a mean light saturation index (Ek) of 138 μmol photons m− 2 s−1 and a ratio between photoprotective carotenoids (PPC) and Chl a (w:w) of 0.2. Remotely sensed data of [Chl a] showed a 32,000 km2 bloom developing south of the MIZ. In effect, our data suggest that the observed under-ice bloom was in fact a bloom developed in open waters south of the ice edge, and that a combination of northward-flowing water masses and southward drifting sea ice effectively positioned the bloom under the sea ice. This have implications for our general understanding of under-ice blooms, publishedVersion © The Author(s) 2018 Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/)

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