Contribution of Calanus species to the mesozooplankton biomass in the Barents Sea

Abstract Copepods from the genus Calanus are crucial prey for fish, seabirds and mammals in the Nordic and Barents Sea ecosystems. The objective of this study is to determine the contribution of Calanus species to the mesozooplankton biomass in the Barents Sea. We analyse an extensive dataset of Cal...

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Bibliographic Details
Published in:ICES Journal of Marine Science
Main Authors: Aarflot, Johanna Myrseth, Skjoldal, Hein Rune, Dalpadado, Padmini, Skern-Mauritzen, Mette
Other Authors: Fields, David, Norwegian Research Council, Integrated Ecosystem Assessment
Format: Article in Journal/Newspaper
Language:English
Published: Oxford University Press (OUP) 2017
Subjects:
Arctic
Barents Sea
Calanus finmarchicus
Calanus glacialis
Calanus hyperboreus
Zooplankton
Copepods
Online Access:http://dx.doi.org/10.1093/icesjms/fsx221
http://academic.oup.com/icesjms/article-pdf/75/7/2342/31236988/fsx221.pdf
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Summary:Abstract Copepods from the genus Calanus are crucial prey for fish, seabirds and mammals in the Nordic and Barents Sea ecosystems. The objective of this study is to determine the contribution of Calanus species to the mesozooplankton biomass in the Barents Sea. We analyse an extensive dataset of Calanus finmarchicus, Calanus glacialis, and Calanus hyperboreus, collected at various research surveys over a 30-year period. Our results show that the Calanus species are a main driver of variation in the mesozooplankton biomass in the Barents Sea, and constitutes around 80% of the total. The proportion of Calanus decreases at low zooplankton biomass, possibly due to a combination of advective processes (low C. finmarchicus in winter) and size selective foraging. Though the Calanus species co-occur in most regions, C. glacialis dominates in the Arctic water masses, while C. finmarchicus dominates in Atlantic waters. The larger C. hyperboreus has considerably lower biomass in the Barents Sea than the other Calanus species. Stages CIV and CV have the largest contribution to Calanus species biomass, whereas stages CI-CIII have an overall low impact on the biomass. In the western area of the Barents Sea, we observe indications of an ongoing borealization of the zooplankton community, with a decreasing proportion of the Arctic C. glacialis over the past 20 years. Atlantic C. finmarchicus have increased during the same period.

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