Physiological adaptations to low temperature and brine exposure in the circumpolar amphipod Gammarus wilkitzkii

Aarset, A. V.; Aunaas, T.

doi:10.1007/bf00297067

Cited by 22 publications

(12 citation statements)

References 18 publications

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“…The results also indicate a passive relationship between the concentrations of haemolymph and seawater Na' and C1-( Fig. 4B and C) (Aarset & Aunaas 1987b). An increased concentration of total FAA in G. wilkitzkii versus elevated salinities has been observed.…”

Section: Brine Exposurementioning

confidence: 60%

“…In the Arctic, however, the sympagic amphipods C. wilkitzkii and 0. glacialis did not tolerate being frozen into the solid sea ice. Instead the amphipods were able to stay away from the advancing ice front during sea ice growth (Aarset & Aunaas 1987b). The intertidal Spitsbergen amphipod Garnrnarus oceanicus, however, could survive being frozen into the solid ice at a temperature of about -6 to -7" C (Aarset & Zachariassen 1988).…”

Section: Cold Hardinessmentioning

confidence: 99%

“…These are proteinaceous compounds which act to stabilise the supercooled state and which have been demonstrated to be present in different categories of supercooled animals (DeVries 1971; Zachariassen & Husby 1982;Denstad et al 1987). However, several tests for thermal hysteresis agents in both Arctic and Antarctic crustaceans were all negative (Table 1.) (Aarset & Aunaas 1987b;Aarset & Zachariassen 1988;Aarset & Torres 1989). The fact that animals cooled in freezing seawater were injured at a…”

Section: Supercooling Thermal Hysteresis Factor ( T H F ) and Nucleamentioning

confidence: 99%

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The ecophysiology of under-ice fauna

Aarset¹

1991

Polar Research

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During exposure to low salinity, the under-ice amphipods Gammarus wilkitzkii and Onisimus glacialis appeared as euryhaline osmoregulators. displaying regulation of haemolymph concentrations of sodium and chloride. Free amino acids took part in the regulation. During freezing and brine formation, the amphipods were freeze-sensitive and did not tolerate being frozen into solid ice. However. they could stay in the vicinity of the ice, conforming osmotically to the ambient brine and thus lowering the melting point of the amphipods' body fluids. This prevented internal ice formation in the absence of antifreeze agents (THF) in the haemolymph. When G. wilkitzkii. 0. glacialis and Apherusa glacialis were exposed to dilute seawater, elevated rates of oxygen consumption and ammonia excretion were observed. The 0 :N atomic ratio was kept nearly constant during hyposmotic stress, indicating protein/lipids as metabolic substrate. Rates of oxygen consumption and ammonia excretion increased with increasing osmotic differences between the haemolymph and the medium. indicating higher energy requirements for osmotic and ionic regulation at low salinities. A minor decrease in haemolymph sodium concentrations coincided with the increased ammonia output during hyposmotic stress. indicating a possible counter ion regulation of NH: and Na+.An increased rate of oxygen consumption, ammonia excretion and O:N ratio versus temperature was observed for all species.

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Section: Brine Exposurementioning

confidence: 60%

Section: Cold Hardinessmentioning

confidence: 99%

Section: Supercooling Thermal Hysteresis Factor ( T H F ) and Nucleamentioning

confidence: 99%

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The ecophysiology of under-ice fauna

Aarset¹

1991

Polar Research

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“…Earlier studies 'Present address: Norwegian Polar Institute,9296 Tromsa, Norway. E-mail: michael.poltermann@npolar.no showed that G. wilkitzkii is physiologically well adapted to the high osmotic stress and the very low temperatures under the Arctic sea ice (Aarset & Aunaas 1987, 1990, Aarset 1991. No information, however, is available yet concerning possible adaptations in growth.…”

Section: Introductionmentioning

confidence: 99%

Growth, production and productivity of the Arctic sympagic amphipod Gammarus wilkitzkii

Poltermann¹

2000

Mar. Ecol. Prog. Ser.

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ABSTRACT. The amphipod Gammarus wilkitzkii Birula IS one of the major macrofauna species permanently inhabiting the subsurface of Arctic sea ice. It reaches an age of 5 yr with a measured maximum body length of 62.3 mm. The growth of this species is best descnbed by the Gompertz growth function, which gives asymptotic final lengths of 69.2 and 64.6 mm respectively for males and females.Individuals of 46 to 52 mm length show the highest individual production, whereas the length class 31 to 36 mm is the most productive within the investigated population. The somatic PIB ratio (productivity) of the investigated G, willutzkii population (0.398 yr.') is low compared to other amphipod species from boreal and polar regions. This is discussed with respect to the permanent low water temperature, the low energy content of the food, and the high mortality of juveniles under Arctic sea ice. The overall growth performance, ' P, of G. wilkitzkii is not significantly different from other Gammarus species Living under boreal conditions. It is therefore assumed that the growth is predominantly determined genetically rather than by environmental conditions.

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“…Healthy fertilized eggs (n = 20) were taken from the incubator and transferred to a glass freezing chamber, containing 10 ml of incubation seawater (33 ppt, 5 °C), and immmersed in the cooling bath. The seawater temperature, in the freezing chamber and in the bath medium, were continously registrated by use of thermocouples connected to a potentiometric recorder (Leeds and Northrup, Speedomax temperature recorder) (Aarset and Aunaas 1987).…”

Section: Freezing Experimentsmentioning

confidence: 99%

Cold hardiness of the eggs of the plaice, Pleuronectes platessa

Aarset¹,

Jørgensen

1988

Polar Biol

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Summary. The pelagic eggs of the plaice, Pleuronectes platessa, at the stage of first heart beat, can tolerate freezing into solid sea ice at temperatures down to -6°C. A long term freezing period of 5 days, at sublethal temperatures of -3 to -4°C, had only a minor effect on the eggs. When the ice was absent from the medium, the eggs supercooled readily to temperatures around -15 ° to -20 °C. However, no thermal hysteresis agents were present in the eggs at low temperature and the cold hardiness therefore seem to rely on a high tolerance to brine solutions at low temperatures.

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Physiological adaptations to low temperature and brine exposure in the circumpolar amphipod Gammarus wilkitzkii

Cited by 22 publications

References 18 publications

The ecophysiology of under-ice fauna

The ecophysiology of under-ice fauna

Growth, production and productivity of the Arctic sympagic amphipod Gammarus wilkitzkii

Cold hardiness of the eggs of the plaice, Pleuronectes platessa

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