Sediment trap samples reveal regional differences in the population structure of Calanus hyperboreus from the Arctic Ocean

• Published in: Journal of Plankton Research
• Main Authors: Tokuhiro, Koki, Matsuno, Kohei, Onodera, Jonaotaro, Sampei, Makoto, Fujiwara, Amane, Harada, Naomi, Niehoff, Barbara, Nöthig, Eva-Maria, Yamaguchi, Atsushi
• Other Authors: Koski, Marja, Young Researchers of the Arctic Challenge for Sustainability, Arctic Challenge for Sustainability II, Grant-in-Aid for Scientific Research, N.H. and Grant-in-Aid for Scientific Research, Japan Society for the Promotion of Science, Hokkaido University
• Format: Article in Journal/Newspaper
• Language: English
• Published: Oxford University Press (OUP) 2024
• Subjects: Ecology; Aquatic Science; Ecology, Evolution, Behavior and Systematics; Arctic; Arctic Ocean; Calanus hyperboreus; Chukchi; Chukchi Sea; Climate change; Fram Strait; Phytoplankton; Zooplankton
• Online Access: http://dx.doi.org/10.1093/plankt/fbad059; https://academic.oup.com/plankt/article-pdf/46/2/183/57138256/fbad059.pdf

Abstract Calanus hyperboreus is one of the dominant copepod species in the Arctic zooplankton communities. The impact of climate change varies among regions within the Arctic, implying that C. hyperboreus populations may be differently affected at different locations, but knowledge on seasonal population dynamics in relation to biogeography is scarce. To fill this gap, we counted C. hyperboreus in samples from sediment traps that were moored from 2009 to 2014 in three regions of the Arctic Ocean (eastern Fram Strait, northern Chukchi Sea and MacKenzie Trough). The C. hyperboreus flux increased between April and May in all regions, likely associated with the ascent from overwintering depth to the surface. In the descent period, high fluxes were observed between July and September in the Fram Strait, between September and November in the northern Chukchi Sea, and between August and October in the MacKenzie Trough, suggesting that the timing of descent varied among the regions characterized by differences in light regime, phytoplankton development and water temperature. The copepodite stage composition in the eastern Fram Strait and the MacKenzie Trough varied with season, suggesting successful local reproduction while it was uniform in the northern Chukchi Sea, possibly because the population is fueled by advection.