Seasonal dynamics and life histories of three sympatric species of Pseudocalanus in two Svalbard fjords

Abstract Small copepods are the most diverse and numerous group in high-latitude zooplankton, yet our knowledge of important species remains poor because of the difficulties involved in correct species identification. In this study, we use a molecular method of identification, a species-specific pol...

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Bibliographic Details
Published in:Journal of Plankton Research
Main Authors: Ershova, Elizaveta A, Nyeggen, Margot U, Yurikova, Daria A, Søreide, Janne E
Other Authors: Russian Foundation for Basic Research, IO RAS, BioDivScen ERA-Net COFUND
Format: Article in Journal/Newspaper
Language:English
Published: Oxford University Press (OUP) 2021
Subjects:
Online Access:http://dx.doi.org/10.1093/plankt/fbab007
http://academic.oup.com/plankt/article-pdf/43/2/209/36805998/fbab007.pdf
Description
Summary:Abstract Small copepods are the most diverse and numerous group in high-latitude zooplankton, yet our knowledge of important species remains poor because of the difficulties involved in correct species identification. In this study, we use a molecular method of identification, a species-specific polymerase chain reaction, to provide the first description of the seasonal dynamics and life histories of the important genus Pseudocalanus in two Svalbard fjords with contrasting environments. We conducted monthly investigations in the relatively warm and ice-free Adventfjorden, supplemented with seasonal samples from the colder, seasonally ice-covered Billefjorden. We found three species of Pseudocalanus (the Arctic P. acuspes and P. minutus, and the boreal P. moultoni). Pseudocalanus acuspes had a distinct annual life cycle and dominated during summer, when it actively reproduced. Surprisingly, the boreal P. moultoni was present year-round in both fjords and was the dominant species during winter; the presence of all life stages of this species throughout the year suggests a more continuous reproduction. The Arctic P. minutus was the rarest of the three species and was likely able to complete its life cycle in Billefjorden but not in Adventfjorden. Our study demonstrates that closely related species may have different life strategies and environmental preferences, which presumably make high-latitude zooplankton communities more resilient to climate change impacts on genus but not necessarily on species level.