Ecophysiology of overwintering in the copepod Neocalanus plumchrus: changes in lipid and protein contents over a seasonal cycle

Campbell, Robert W.; Boutillier, Palmira; Dower, John F.

doi:10.3354/meps280211

Cited by 26 publications

(13 citation statements)

References 62 publications

(71 reference statements)

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“…We hypothesize that copepods unable to descend to depths where phase changes of wax esters facilitate neural buoyancy would incur additional metabolic costs associated with constant swimming. This is consistent with higher rates of lipid utilization during winter in neritic (Campbell et al 2004;Hill 2009) compared to deep-water habitats (Jó nasdó ttir 1999). Although C. finmarchicus is often abundant in neritic waters, its main habitat is the open ocean and evolutionary pressures acting on this species would be primarily linked to this deep-water environment (Falk-Petersen et al 2009).…”

Section: Discussionsupporting

confidence: 71%

“…However, some calanoid species can also successfully overwinter in comparatively shallow coastal and shelf-sea habitats. These populations tend to overwinter at depths of 100 to 300 m, do not vertically migrate (Nicholls 1933), do not feed (Marshall and Orr 1972), have reduced respiration rates compared to summer populations (Marshall and Orr 1958), and have high rates of lipid utilization (Campbell et al 2004). The population of C. finmarchicus in Loch Etive undoubtedly belongs to the latter category.…”

Section: Discussionmentioning

confidence: 99%

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Composition of wax esters is linked to diapause behavior of Calanus finmarchicus in a sea loch environment

Clark

Brierley

Pond

2011

Limnology & Oceanography

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We studied the seasonal lipid dynamics of Calanus finmarchicus from Loch Etive, a semi-enclosed fjordic environment on the west coast of Scotland, in relation to the diapause behavior of this species. Levels of total lipid and triacylglycerol in individual copepodid stage V (CVs) exhibited clear seasonal trends, with highest levels in June and progressively decreasing through late summer to winter. Wax esters in CVs were more variable, but followed a similar pattern. An index of the level of unsaturation of wax esters, effectively an indicator of the levels of polyunsaturated fatty acids in the wax ester reserves, were highest in midsummer and declined progressively through autumn and winter. Fatty acid analysis of total lipid in the CVs confirmed that the amounts of polyunsaturated fatty acids in the wax esters decreased, while amounts of saturated and monounsaturated fatty acids remained comparatively stable. Polyunsaturated wax esters are selectively catabolized by C. finmarchicus during diapause. Previous studies have linked unsaturation of wax esters in calanoid copepods to the initiation of diapause and buoyancy control, and we hypothesize that selective catabolism of polyunsaturated wax esters is linked to the processes of diapause termination and ascent to surface waters.

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Section: Discussionsupporting

confidence: 71%

Section: Discussionmentioning

confidence: 99%

Composition of wax esters is linked to diapause behavior of Calanus finmarchicus in a sea loch environment

Clark

Brierley

Pond

2011

Limnology & Oceanography

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“…In the open ocean, C. finmarchicus diapauses at depths between 400 m and 1000 m (Hirche ; Heath et al ) where seasonal changes of environmental parameters are minimal or absent. The potential lack of seasonal cues for triggering emergence has led to the proposal of an hourglass model based on the gradual depletion of wax esters (Miller et al ; Campbell et al ; Saumweber and Durbin ; Clark et al ) mediated by lipid‐derived hormones (Irigoien ; Pond et al ) or based on continuous slow development (Hind et al ). However, our results from Loch Etive contradict this view.…”

Section: Discussionmentioning

confidence: 99%

Calanus finmarchicus seasonal cycle and diapause in relation to gene expression, physiology, and endogenous clocks

Häfker

Teschke

Last

et al. 2018

Limnology & Oceanography

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The copepod Calanus finmarchicus plays a crucial role in the north Atlantic food web. Its seasonal life cycle involves reproduction and development in surface waters before overwintering in diapause at depth. Although diapause has been studied for more than a century, the factors responsible for the initiation and termination of it are still unclear. Endogenous clocks have been identified as potent tools for photoperiod measurement and seasonal rhythmicity in many terrestrial species, but knowledge of these remains scarce in the marine realm. Focusing on the dominant CV copepodid stage, we sampled a population of C. finmarchicus from a Scottish sea loch to characterize population dynamics, several physiological parameters, and diel and seasonal expression rhythms of 35 genes representing different metabolic pathways, including the circadian clock machinery. This generated a detailed overview of the seasonal cycle of C. finmarchicus including the most extensive field dataset on circadian clock gene expression in a marine species to date. Gene expression patterns revealed distinct gene clusters upregulated at different phases of the copepod's seasonal cycle. While diel clock cycling was restricted to the active spring/summer phase, many clock genes exhibited the highest expression during diapause. Our results provide new insights into diapause on physiological and genetic levels. We suggest that photoperiod, in interaction with internal and external factors (lipid content, temperature, food availability) and the endogenous clock mechanism, plays an important role in the timing of diapause in C. finmarchicus.

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“…N. plumchrus C5 stages enter deep waters in July and remain in diapause from July to January, followed by deep-water reproduction in January and February, and ascend as nauplii to surface waters (Fulton 1973). Campbell et al (2004) observed that N. plumchrus C5 stages, collected in the Strait of Georgia, use approx. 1 ⁄ 4 of their wax ester stores for overwintering prior to moulting.…”

Section: Diapausementioning

confidence: 99%

Lipid storage in marine zooplankton

Lee

Hagen²,

Kattner³

2006

Mar. Ecol. Prog. Ser.

646

548

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Zooplankton storage lipids play an important role during reproduction, food scarcity, ontogeny and diapause, as shown by studies in various oceanic regions. While triacylglycerols, the primary storage lipid of terrestrial animals, are found in almost all zooplankton species, wax esters are the dominant storage lipid in many deep-living and polar zooplankton taxa. Phospholipids and diacylglycerol ethers are the unique storage lipids used by polar euphausiids and pteropods, respectively. In zooplankton with large stores of wax esters, triacylglycerols are more rapidly turned over and used for short-term energy needs, while wax esters serve as long-term energy deposits. Zooplankton groups found in polar, westerlies, upwelling and coastal biomes are characterized by accumulation of large lipid stores. In contrast, zooplankton from the trades/tropical biomes is mainly composed of omnivorous species with only small lipid reserves. Diapausing copepods, which enter deep water after feeding on phytoplankton during spring/summer blooms or at the end of upwelling periods, are characterized by large oil sacs filled with wax esters. The thermal expansion and compressibility of wax esters may allow diapausing copepods and other deep-water zooplankton to be neutrally buoyant in cold deep waters, and they can thus avoid spending energy to remain at these depths. Lipid droplets are often noted in zooplankton ovaries, and a portion of these droplets can be transferred to developing oocytes. In addition to lipid droplets, zooplankton eggs have yolks with lipovitellin, a lipoprotein with approximately equal amounts of protein and lipid. The lipovitellin lipid is predominantly phosphatidylcholine, so during reproduction females must convert a portion of their storage lipid into this phospholipid. Developing embryos use their lipovitellin and lipid droplets for energy and materials until feeding begins. The various functions storage lipids serve during the different life history stages of zooplankton are very complex and still not fully understood and hence offer a multitude of fascinating research perspectives.

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Ecophysiology of overwintering in the copepod Neocalanus plumchrus: changes in lipid and protein contents over a seasonal cycle

Cited by 26 publications

References 62 publications

Composition of wax esters is linked to diapause behavior of Calanus finmarchicus in a sea loch environment

Composition of wax esters is linked to diapause behavior of Calanus finmarchicus in a sea loch environment

Calanus finmarchicus seasonal cycle and diapause in relation to gene expression, physiology, and endogenous clocks

Lipid storage in marine zooplankton

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