Plasticity in dormancy behaviour of Calanoides acutus in Antarctic coastal waters. (3rd April 2020)

• Record Type: Journal Article
• Authors: Biggs, Tristan E G; Brussaard, Corina P D; Evans, Claire; Venables, Hugh J; Pond, David W
• Editors: Ji, Rubao
• Is Part Of: ICES journal of marine science. Volume 77:Number 5(2020)
• Page Start: 1738
• Page End: 1751
• Publication Date: 2020-04-03
• Subjects: copepod -- dormancy -- life cycle -- lipids -- phytoplankton -- wax ester unsaturation; Ocean -- Periodicals; Fisheries -- Periodicals; Fishes -- Periodicals; Marine biology -- Bibliography -- Periodicals; 551.4605
• DOI: 10.1093/icesjms/fsaa042
• Languages: English
• ISSNs: 1054-3139

Abstract

Abstract: Copepods that enter dormancy, such as Calanoides acutus, are key primary consumers in Southern Ocean food webs where they convert a portion of the seasonal phytoplankton biomass into a longer-term energetic and physiological resource as wax ester (WE) reserves. We studied the seasonal abundance and lipid profiles of pre-adult and adult C. acutus in relation to phytoplankton dynamics on the Western Antarctic Peninsula. Initiation of dormancy occurred when WE unsaturation was relatively high, and chlorophyll a (Chl a ) concentrations, predominantly attributable to diatoms, were reducing. Declines in WE unsaturation during the winter may act as a dormancy timing mechanism with increased Chl a concentrations likely to promote sedimentation that results in a teleconnection between the surface and deep water inducing ascent. A late summer diatom bloom was linked to early dormancy termination of females and a second spawning event. The frequency and duration of high biomass phytoplankton blooms may have consequences for the lifespan of the iteroparous C. acutus females (either 1 or 2 years) if limited by a total of two main spawning events. Late summer recruits, generated by a second spawning event, likely benefitted from lower predation and high phytoplankton food availability. The flexibility of copepods to modulate their life-cycle strategy in response to bottom-up and top-down conditions enables individuals to optimize their probability of reproductive success in the very variable environment prevalent in the Southern Ocean.