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Biogeosciences An interactive open-access journal of the European Geosciences Union
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Volume 12, issue 6
Biogeosciences, 12, 2019–2046, 2015
https://doi.org/10.5194/bg-12-2019-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

Special issue: Catastrophic reduction of sea ice in the Arctic Ocean...

Biogeosciences, 12, 2019–2046, 2015
https://doi.org/10.5194/bg-12-2019-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 27 Mar 2015

Research article | 27 Mar 2015

Flux variations and vertical distributions of siliceous Rhizaria (Radiolaria and Phaeodaria) in the western Arctic Ocean: indices of environmental changes

T. Ikenoue1,2,3, K. R. Bjørklund2, S. B. Kruglikova4, J. Onodera3, K. Kimoto3, and N. Harada3 T. Ikenoue et al.
  • 1Department of Earth and Planetary Sciences, Graduate School of Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
  • 2Natural History Museum, Department of Geology, University of Oslo, P.O. Box 1172 Blindern, 0318 Oslo, Norway
  • 3Research and Development Center for Global Change, JAMSTEC, Natsushima-cho 2-15, Yokosuka 237-0061, Japan
  • 4P.P. Shirshov Institute of Oceanology, Russian Academy of Sciences, Nakhimovsky Prospect 36, 117883 Moscow, Russia

Abstract. The vertical distribution of radiolarians was investigated using a vertical multiple plankton sampler (100–0, 250–100, 500–250, and 1000–500 m water depths, 62 μm mesh size) at the Northwind Abyssal Plain and southwestern Canada Basin in September 2013. To investigate seasonal variations in the flux of radiolarians in relation to sea ice and water masses, a time-series sediment trap system was moored at Station NAP (75°00´ N, 162°00´ W; bottom depth 1975 m) in the western Arctic Ocean during October 2010–September 2012. The radiolarian flux was comparable to that in the North Pacific Ocean. Amphimelissa setosa was dominant during the season with open water as well as at the beginning and end of the seasons with sea-ice cover. During the sea-ice-cover season, however, oligotrophic and cold-water-tolerant actinommids were dominant, productivity of Radiolaria was lower, and species diversity was greater. These suggest that the dynamics of sea ice are a major factor affecting the productivity, distribution, and composition of the radiolarian fauna.

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