A year-round study on metabolic enzymes and body composition of the Arctic copepod Calanus glacialis: implications for the timing and intensity of diapause
- 363 Downloads
Knowledge on the capability of zooplankton to adapt to the rapidly changing environmental conditions in the Arctic is crucial to predict future ecosystem processes. The key species on the Arctic shelf, the calanoid copepod Calanus glacialis, grows and accumulates lipid reserves in spring and summer in surface waters. The winter is spent in dormancy in deeper water layers with low metabolic activity. As timing and intensity of metabolic changes have been poorly investigated, our study aims to characterize the physiology of C. glacialis over an entire year, from July 2012 to July 2013. We followed anabolic and catabolic enzyme activities and the biochemical composition of this species, taking depth-stratified samples once a month in Billefjorden, a high-Arctic sill fjord. A large part of the population had migrated to depths >100 m by July 2012. Only thereafter, anabolic activities decreased slowly, suggesting that low metabolism is related to ceased feeding rather than to endogenous regulation. During overwintering, anabolic enzyme activities were reduced by half as compared to peak activities in spring. The biochemical composition of the copepods changed little from July to December. Then, the lipid catabolic activity increased and the lipid content decreased, likely fuelling moulting and gonad maturation. The protein content did not change significantly during winter, suggesting that proteins are not much catabolized during that time. The relatively high metabolic activity in C. glacialis in winter suggests that this species is not entering a true diapause and should thus be able to respond flexible to changing environmental conditions.
KeywordsTotal Lipid Content Tukey Post Calanoid Copepod Copepodite Stage Metabolic Enzyme Activity
Analysis of variance
- CIV, CV
Copepodite stage IV and V
Enzyme commission number
Coast guard vessels
Nicotinamide adenine dinucleotide
The University Centre in Svalbard
Working party 2 plankton sampling net
Working party 3 plankton sampling net
We thank UNIS logistics, and the crew and the scientists of the RV Helmer Hanssen and of the small motorboat Farm for their support during the field campaigns and cruises. We are also very grateful for all the help in field by Maja K. Hatlebakk and Lauris Boissonnot. For analysing the lipid content, we thank Martina Vortkamp. Dr. Mathias Teschke contributed with valuable comments to the analyses of our results. We also thank three anonymous referees for their thorough reviews and helpful comments.
This research was part of the project CLEOPATRA II: Climate effects on food quality and trophic transfer in the Arctic marginal ice zone, funded by the Research Council of Norway (Project ID 216537). Daniela Freese was financed from the Helmholtz Graduate School for Polar and Marine Research (POLMAR, Project ID VH-GS-200). Part of the fieldwork was also financed by an Arctic Field Grant to D. Freese (Research Council of Norway; Project ID 227555).
Compliance with ethical standards
All applicable national and institutional guidelines for the care and use of animals were followed.
- Alekseev VR, Hwang J-S, Tseng M-H (2006) Diapause in aquatic invertebrates: What’s known and what’s next in research and medical application? J Mar Sci Technol 14:269–286Google Scholar
- Bonnet D, Richardson A, Harris R, Hirst A, Beaugrand G, Edwards M, Ceballos S, Diekman R, López-Urrutia A, Valdes L, Carlotti F, Molinero JC, Weikert H, Greve W, Lucic D, Albaina A, Yahia ND, Umani SF, Miranda A, dos Santos A, Cook K, Robinson S, Fernandez de Puelles ML (2005) An overview of Calanus helgolandicus ecology in European waters. Prog Oceanogr 65:1–53CrossRefGoogle Scholar
- Clark KAJ, Brierley AS, Pond DW, Smith VJ (2013) Changes in seasonal expression patterns of ecdysone receptor, retinoid X receptor and an A-type allatostatin in the copepod, Calanus finmarchicus, in a sea loch environment: an investigation of possible mediators of diapause. Gen Comp Endocrinol 189:66–73CrossRefGoogle Scholar
- Conover RJ (1962) Metabolism and growth in Calanus hyperboreus in relation to its life cycle. J Cons Int Expl Mer 153:190–197Google Scholar
- Danks HV (1987) Insect dormancy: an ecological perspective. Biol Surv Can Mono 1:1–439Google Scholar
- Elgmork K, Nilssen JP (1978) Equivalence of copepod and insect diapause. Verh Internat Verein Theor Angew Limnol 20:2511–2517Google Scholar
- Head EJH, Conover RJ (1983) Induction of digestive enzymes in Calanus hyperboreus. Mar Biol Lett 4:219–231Google Scholar
- Hirche H-J (1998) Dormancy in three Calanus species (C. finmarchicus, C. glacialis and C. hyperboreus) from the North Atlantic. Arch Hydrobiol Spec Issues Adv Limnol 52:359–369Google Scholar
- Kosobokova KN (1990) Age-related and seasonal changes in the biochemical makeup of the copepod Calanus glacialis as related to the characteristics of its life cycle in the White Sea. Oceanology 30:103–109Google Scholar
- Miller CB, Grigg H (1991) An experimental study of the resting phase in Calanus finmarchicus (Gunnerus). Bull Plankton Soc Jpn 177:479–493Google Scholar
- Søreide JE, Leu E, Berge J, Graeve M, Falk-Petersen S (2010) Timing of blooms, algal food quality and Calanus glacialis reproduction and growth in a changing Arctic. Glob Change Biol 16:3154–3163Google Scholar
- Stitt M (1984) Citrate synthase (condensing enzyme). In: Bergmeyer HU (ed) Methods of enzymatic analysis, vol 4. Chemie, Weinheim, pp 353–358Google Scholar
- Uye S (1985) Resting eggs production as a life history strategy of marine planktonic copepods. Bull Mar Sci 37:440–449Google Scholar