<i>Meganyctiphanes norvegica</i>(Crustacea: Euphausiacea) In the Kattegat: Studies on the horizontal distribution in relation to hydrography and zooplankton

Búchholz, Friedrich; Boysen-Ennen, E.

doi:10.1080/00785326.1988.10430820

Cited by 26 publications

(21 citation statements)

References 11 publications

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“…Surface waters range from more than 16 • C during summer to less than 1 • C during January and February (Buchholz & Boysen, 1988). Steep temperature gradients and a difference of ca.…”

Section: Hydrography and Bathymetrymentioning

confidence: 99%

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Vertical migratory behaviour of the euphausiid, Meganyctiphanes norvegica, and its dispersion in the Kattegat Channel

Tarling

Matthews

Saborowski³

et al. 1998

Recruitment, Colonization and Physical-Chemical Forcing in Marine Biological Systems

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The euphausiid Meganyctiphanes norvegica (Northern Krill) is predominantly an oceanic species common to the North Atlantic and adjacent seas. In the Kattegat the species concentrates in a series of depressions in the Kattegat Channel east of the island of Laesø which represent havens of marine conditions beneath the low salinity Baltic outflow.The vertical migratory behaviour of Meganyctiphanes results in it encountering considerable contrasts in physical conditions during its diurnal cycle. This behaviour and the resulting physical experience of the animals were investigated by means of a combination of net sampling and ADCP transects across the Alkor Deep (131 m) in summer (18-19/7/96) and winter (9-10/3/97).In both summer and winter the krill tended to concentrate within the basin during daytime and to disperse in the upper layers at night. The period of dispersion was longer in winter (17.00-05.00 h) than in summer (23.00-02.00 h). The complex layering of different wind-induced and tidal current systems acted to advect the krill away from the basin during their upward phase at night. ADCP measurements showed that in summer the krill would be advected SSW at an average rate of 3 cm s −1 , but that in winter they would be advected WSW at 3.2 cm s −1 . Calculations show that the krill would be capable of swimming against such currents without increasing their standard metabolism and that their distribution in the vicinity of the basin seems to be determined more by biotic than by abiotic factors.

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“…Surface waters range from more than 16 • C during summer to less than 1 • C during January and February (Buchholz & Boysen, 1988). Steep temperature gradients and a difference of ca.…”

Section: Hydrography and Bathymetrymentioning

confidence: 99%

“…Above the halocline, values seldom exceed 20 psu and are generally lower during summer months. Below the halocline, salinities range between 30 and 34 psu for most of the year but are higher during the windy months of October and November (Buchholz & Boysen, 1988).…”

Section: Hydrography and Bathymetrymentioning

confidence: 99%

Vertical migratory behaviour of the euphausiid, Meganyctiphanes norvegica, and its dispersion in the Kattegat Channel

Tarling

Matthews

Saborowski³

et al. 1998

Recruitment, Colonization and Physical-Chemical Forcing in Marine Biological Systems

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“…Interestingly, this fin whale population seems to be stably resident in the Ligurian Sea and was shown to be genetically isolated (Bérubé et al 1998). At least 2 other self-maintaining krill populations are well documented in the Baltic Sea: one in the Skagerrak Sea, which indirectly sustains the active cod and anchovy fishery, and a second in the Kattegat Sea, which is specifically associated with the Laesø Deep depression, where Baltic and Skagerrak waters mix together (Buchholz & Boysen-Ennen 1988, Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

Genetic differentiation and local temporal stability of population structure in the euphausiid Meganyctiphanes norvegica

Papetti¹,

Zane²,

Bortolotto³

et al. 2005

Mar. Ecol. Prog. Ser.

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Meganyctiphanes norvegica (M. Sars 1856), the northern krill, is the largest and most abundant euphausiid species in the northern hemisphere, where it represents a key component of many pelagic communities. Although planktonic, krill could be considered a nektonic organism, as it is capable of active movements. This behaviour may be adaptive, because it allows these organisms to maintain their geographic position, leading to stable population structure, despite being continuously exposed to the heterogeneous oceanic conditions. By means of single-strand conformation polymorphism and DNA sequencing, we analyzed allelic variation of the Subunit 1 of NADH dehydrogenase mtDNA locus in 23 populations of the northern krill Meganyctiphanes norvegica, from 15 locations spanning the distribution range of the species. Analysis of the data indicated that the genetic structure, as revealed by analysis of population samples collected at the same site in consecutive years, was stable during that sampling period. Our results revealed the existence of 4 genetically and geographically distinct gene pools of M. norvegica, 2 occurring in the NE Atlantic ('northern' NE Atlantic and 'southern' NE Atlantic), 1 in the NW Atlantic, and 1 in the Mediterranean (Ligurian) Sea.

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“…However, krill rely strongly on copepods, these being advected from the Baltic and the deep Skagerrak currents . As a consequence, a long phase of enhanced production or availability of plankton lasts from April to November (Buchholz and Boysen-Ennen 1988). The winter-summer difference during the cruises was not pronounced.…”

Section: Trophic Conditionsmentioning

confidence: 89%

“…1) were chosen where abundant swarms of krill had been regularly encountered and studied previously: the Arran Deep in the Clyde Sea, western Scotland (Mauchline 1960), the Läsö Deep in the Danish Kattegat (Buchholz and Boysen-Ennen 1988), and the frontal system in the Ligurian Sea, which was located at the beginning of the cruises by conductivitytemperature-depth sonde (CTD) on a section between Nice and Calvi (Corse) (Labat and Cuzin-Roudy 1996).…”

Section: Locationsmentioning

confidence: 99%

Metabolic and enzymatic adaptations in northern krill,Meganyctiphanes norvegica, and Antarctic krill,Euphausia superba

Búchholz¹,

Saborowski²

2000

Can. J. Fish. Aquat. Sci.

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Abstract:The Antarctic krill, Euphausia superba, is restricted to the Antarctic Ocean. The northern krill, Meganyctiphanes norvegica, is extremely widely distributed from the arctic North Atlantic to the warm Mediterranean. Respiration measurements showed no seasonal differences in rates determined in krill from the thermally stable Clyde Sea (Scotland) and the cooler but variable Danish Kattegat. In the warm Ligurian Sea, where temperatures are stable, krill showed higher rates in April than in September, indicating reactions to the short but intensive productive season. Krill can passively benefit from enhancements of overall metabolism when ascending into upper, warmer water strata during their pronounced diel vertical migration. Michaelis-Menten constants (K m ) of citrate synthase (CS) were compared. In terms of respiration and enzyme regulation, krill from the Ligurian Sea stand apart: temperature and nutrition appear to be of different influence, relatable to genetic differentiation in the species. In contrast, K m of CS in E. superba is temperature independent, highlighting the species' stenothermal physiology. A basal level of activity of digestive enzymes ensures immediate utilization of patchy food sources. Specific induction, including that of chitinases, indicating omnivory in both species, underlines krill's exceptional capacity to adapt to highly variable trophic environments. Processes of moult, growth, and reproduction are locally and seasonally adjusted.Résumé : Le krill antarctique, Euphausia superba, n'habite que l'Océan antarctique, alors que le krill nordique, Meganyctiphanes norvegica, possède une répartition géographique très étendue qui va de la région arctique de l'Atlantique Nord aux eaux chaudes de la Méditerranée. Les taux respiratoires n'accusent pas de variation saisonnière chez le krill de la mer de Clyde en Écosse, un milieu à forte stabilité thermique, ni chez celui du Cattégat danois, une mer plus froide et plus changeante. Dans la mer Ligurienne, où les températures sont chaudes et stables, le krill a des taux respiratoires plus élevés en avril qu'en septembre, en réaction à la courte mais intense saison de production. Le krill peut bénéficier passivement d'un accroissement général de son métabolisme lorsqu'il se déplace vers les couches d'eau supérieures plus chaudes durant sa migration verticale quotidienne marquée. Nous avons comparé les constantes de Michaelis-Menten (K m ) de la citrate synthase (CS). En ce qui a trait à la respiration et la régulation enzymatique, le krill de la mer Ligurienne fait bande à part: la température et la nutrition semblent y avoir une influence particulière, à cause d'une différentiation génétique chez l'espèce. En revanche, la K m de la citrate synthase est indépendante de la température chez E. superba, une caractéristique physiologique d'une espèce sténotherme. Le maintien d'un niveau d'activité de base chez les enzymes digestives permet l'utilisation immédiate de ressources alimentaires à répartition contagieuse. L'induction spécifique, e...

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Meganyctiphanes norvegica(Crustacea: Euphausiacea) In the Kattegat: Studies on the horizontal distribution in relation to hydrography and zooplankton

Cited by 26 publications

References 11 publications

Vertical migratory behaviour of the euphausiid, Meganyctiphanes norvegica, and its dispersion in the Kattegat Channel

Vertical migratory behaviour of the euphausiid, Meganyctiphanes norvegica, and its dispersion in the Kattegat Channel

Genetic differentiation and local temporal stability of population structure in the euphausiid Meganyctiphanes norvegica

Metabolic and enzymatic adaptations in northern krill,Meganyctiphanes norvegica, and Antarctic krill,Euphausia superba

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