Effect of short-term starvation of adult Antarctic krill, Euphausia superba, at the onset of summer

Auerswald, Lutz; Pape, Carsten; Stübing, Dorothea; Lopata, Andreas L.; Meyer, Bettina

doi:10.1016/j.jembe.2009.09.011

Cited by 21 publications

(22 citation statements)

References 45 publications

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“…The slowdown effect is most evident from the course of the respiration rate. The decline was steepest in the first week of starvation and resembled results of previous short-term starvation experiments (Atkinson et al 2002;Auerswald et al 2009), although in the present study krill was in a better condition prior to experimentation (see above). Such a swift reduction in metabolism is more typical of animals that do not store large reserves of energy metabolites such as the copepod Temora longicornis (Kreibich et al 2008).…”

Section: Physical and Metabolic Changes During Starvationsupporting

confidence: 90%

“…came closest to that previously measured in krill collected during late spring (Auerswald et al 2009;Meyer et al 2010), the season that allows krill to start feeding ad libitum on the massive algal blooms and replenish their energy reserves that were depleted during the winter period. The initial level of TL, the most important storage metabolite in krill, was approximately 10 % of DM, well above the 5 % deemed necessary for membrane functioning and, hence, survival (Hagen et al 1996;2001), but far below maximum levels of around 45 % measured from field caught krill in autumn and just before winter (FalkPetersen et al 2000;Atkinson et al 2002).…”

supporting

confidence: 75%

“…The relatively low lipid content is also reflected in the C:N ratio of about 4, much lower than that of 7 measured in the field at the end of the feeding period (Atkinson et al 2002). There is also a distinctly different composition of lipids than found previously (Auerswald et al 2009): most likely caused by a higher accumulation of the depot lipid class triacylglycerol (TAG: 22 % of TL in abdomen) during the long feeding period prior to the experiment; phospholipid percentage was relatively lower (*70 %) than usually found in spring and this also caused a much higher TAG : ST ratio of about eight. The O:N ratio of 32 indicated that lipid compounds, either via digestion or from body reserves, were preferentially catabolised.…”

contrasting

confidence: 61%

“…Recent research indicated that endogenous (inherent) mechanisms exist to synchronise the seasonal and circadian rhythmicity of metabolic and physiological output (Teschke et al 2007(Teschke et al , 2008(Teschke et al , 2011Mazzotta et al 2010), triggered by light (Seear et al 2009;Teschke et al 2011;Brown et al 2013). On the other hand, it was clearly shown in short-term starvation experiments that food availability does play a role: even after only 18 days without food, krill switched to a mode that reduced energy consumption and initiated consumption of body lipids (Atkinson et al 2002;Auerswald et al 2009). A combined regulation of metabolism by the triggers, light and food, seems therefore likely.…”

Section: Original Papermentioning

confidence: 99%

“…In krill, these enzymes were useful to describe a shift from a more protein-based metabolism to the consumption of lipid reserves (Auerswald et al 2009;Meyer et al 2010).…”

Section: Original Papermentioning

confidence: 99%

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Physiological response of adult Antarctic krill, Euphausia superba, to long-term starvation

et al. 2015

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Adult Euphausia superba survive winter without or with little feeding. It is not exactly known whether the scarcity of food or an internal clock, set by the natural Antarctic light regime, are responsible for non-feeding. Our research questions were therefore the following: (1) How will physiological and biochemical conditions of krill change during long-term starvation at constant light regime? (2) If and how do enzyme activities change during such starvation? (3) What is the influence of food availability versus that of light regime? To answer these questions, adult krill were starved under laboratory conditions for 12 weeks with constant light regime (12:12; dark/light) and the impact on physiological functions was studied. Initial experimental condition of krill resembled the condition of late spring krill in the field with fully active metabolism and low lipid reserves. Metabolic activity and activities of enzymes catabolising lipids decreased after the onset of starvation and remained low throughout, whereas lipid reserves declined and lipid composition changed. Mass and size of krill decreased while the inter-moult period increased. Depletion of storage-and structural metabolites occurred in the order of depot lipids and glycogen reserves after onset of starvation until proteins were almost exclusively used after 6-7 weeks of starvation. Results confirmed various proposed overwintering mechanisms such as metabolic slowdown, slow growth or shrinkage and use of lipid reserves. However, these changes were set in motion by food shortage only, i.e. without the trigger of a changing light regime.

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Section: Physical and Metabolic Changes During Starvationsupporting

confidence: 90%

supporting

confidence: 75%

contrasting

confidence: 61%

Section: Original Papermentioning

confidence: 99%

“…In krill, these enzymes were useful to describe a shift from a more protein-based metabolism to the consumption of lipid reserves (Auerswald et al 2009;Meyer et al 2010).…”

Section: Original Papermentioning

confidence: 99%

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Physiological response of adult Antarctic krill, Euphausia superba, to long-term starvation

et al. 2015

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Non-microcystin and non-cylindrospermopsin producing cyanobacteria affect the biochemical responses and behavior ofDaphnia magna

Dao¹,

Ortiz-Rodríguez²,

Do-Hong

et al. 2013

Internat. Rev. Hydrobiol.

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Cyanobacterial blooms affect aquatic ecosystems due to their capability of producing cyanotoxins (e.g., microcystins, MC; cylindrospermopsin, CYN) and other bioactive compounds. Filter feeding zooplankton are amongst the first organisms affected and research has mainly focused on their interactions with toxic cyanobacteria. We investigated oxidative stress, biotransformation and energetic responses of Daphnia magna after exposure to cyanobacterial extracts and behavioral changes of the animals exposed to living cells of non‐MC and non‐CYN producing strains. Enzyme and energetic responses were measured in time kinetic experiments, using extracts of Microcystis botrys, M. wesenbergii, Aphanizomenon aphanizomenoides, Cylindrospermopsis raciborskii, corresponding to 10 mg DW L−1. In behavioral experiments, D. magna was exposed to living cells of Microcystis aeruginosa, A. aphanizomenoides, Dolichospermum circinalis, C. raciborskii, at the density of 400 000 cells mL−1 using a Daphnia toximeter equipment. Despite not producing MC or CYN, some cyanobacterial extracts caused significant increase of biotransformation enzyme, especially catalase, activities from the exposed D. magna after a longer incubation. Total carbohydrates and glycogen contents were increased but the activity of one of the involved enzymes, the malate dehydrogenase, was not changed. Animals' behavior (e.g., swimming, position within water column) was altered in exposures to cultures of C. raciborskii and D. circinalis. These physiological and behavioral alterations indicate stress, which may impair overall performance of zooplankton at the environmental realistic chronic exposure scenario.

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Trophic niche partitioning of dominant North‐Atlantic krill species, Meganyctiphanes norvegica, Thysanoessa inermis, and T. raschii

Cabrol

Trombetta

Amaudrut

et al. 2018

Limnology & Oceanography

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Different krill species have a pivotal position in many marine food webs by both preying upon several trophic levels and being forage species for consumers. Within these food webs, different krill species coexist, though it remains unclear what mechanisms allow for the coexistence, for instance, of northern krill species in subarctic environments. Here, we hypothesize that the stable coexistence of sympatric krill species is based on trophic niche partitioning related to seasonal trade‐offs between their respective food preferences, their energy needs, and prey availability. To test our hypothesis, we analyzed the diets, feeding selectivity, and lipid composition of three coexisting northern krill species (Meganyctiphanes norvegica, Thysanoessa inermis, and Thysanoessa raschii) throughout 1 yr using a multimarker approach. We assessed lipid classes, fatty acids, and stable isotope signatures of krill and potential food sources (27 groups, from phytoplankton to lipid‐rich copepods) to elucidate seasonal variation of niche utilization. Results revealed strong trophic niche separation occurring at a very fine trophic scale (species level) throughout the year. The three krill species showed different degrees of food specialization rather than being purely opportunistic as classically proposed. Feeding on copepod prey was important to accumulate energy reserves for overwintering and subsequent rebuilding of energy reserves. Energy reserve utilization might reduce potential competition for the limited available resources, especially under low food conditions.

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Effect of short-term starvation of adult Antarctic krill, Euphausia superba, at the onset of summer

Cited by 21 publications

References 45 publications

Physiological response of adult Antarctic krill, Euphausia superba, to long-term starvation

Physiological response of adult Antarctic krill, Euphausia superba, to long-term starvation

Non-microcystin and non-cylindrospermopsin producing cyanobacteria affect the biochemical responses and behavior ofDaphnia magna

Trophic niche partitioning of dominant North‐Atlantic krill species, Meganyctiphanes norvegica, Thysanoessa inermis, and T. raschii

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