Eat or sleep : availability of winter prey explains mid-winter and spring activity in an arctic Calanus population
Hobbs, Laura and Banas, Neil S. and Cottier, Finlo R. and Berge, Jørgen and Daase, Malin (2020) Eat or sleep : availability of winter prey explains mid-winter and spring activity in an arctic Calanus population. Frontiers in Marine Science, 7. 541564. ISSN 2296-7745 (https://doi.org/10.3389/fmars.2020.541564)
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Abstract
Copepods of the genus Calanus have adapted to high levels of seasonality in prey availability by entering a period of hibernation during winter known as diapause, but repeated observations of active Calanus spp. have been made in January in high latitude fjords which suggests plasticity in over-wintering strategies. During the last decade, the period of Polar Night has been studied intensively in the Arctic. A continuous presence of an active microbial food web suggests the prevalence of low-level alternative copepod prey (such as microzooplankton) throughout this period of darkness. Here we provide further evidence of mid-winter zooplankton activity using a decadal record of moored acoustics from Kongsfjorden, Svalbard. We apply an individual based life-history model to investigate the fitness consequences of a range of over-wintering strategies (in terms of diapause timing and duration) under a variety of prey availability scenarios. In scenarios of no winter prey availability ((Formula presented.)), the optimal time to exit diapause is in March. However, as P win increases (up to 40μgCL −1), there is little fitness difference in copepods exiting diapause in January compared to March. From this, we suggest that Calanus are able (in energetic terms) to either i) exit diapause early to deal with uncertainty in spring bloom timing, or ii) remain active throughout winter if diapause is not possible (i.e., environment not deep enough, or not enough lipid reserves built up over the previous summer). The range of viable overwintering strategies increases with increasing P win, suggesting that there is more flexibility for Calanus spp. in a scenario of non-zero P win.
ORCID iDs
Hobbs, Laura, Banas, Neil S. ORCID: https://orcid.org/0000-0002-1892-9497, Cottier, Finlo R., Berge, Jørgen and Daase, Malin;-
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Item type: Article ID code: 73999 Dates: DateEvent25 September 2020Published17 August 2020Accepted9 March 2020SubmittedSubjects: Science > Mathematics Department: Faculty of Science > Mathematics and Statistics
Strategic Research Themes > Ocean, Air and SpaceDepositing user: Pure Administrator Date deposited: 29 Sep 2020 10:36 Last modified: 27 Sep 2024 01:16 URI: https://strathprints.strath.ac.uk/id/eprint/73999