Ecophysiological studies on arthropods from Spitsbergen

Aunaas, T.; Baust, John G.; Zachariassen, Karl Erik

doi:10.3402/polar.v1i3.6990

Cited by 25 publications

(18 citation statements)

References 6 publications

(1 reference statement)

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“…In invertebrates that really do rely on prolonged supercooling for winter survival, thermal hysteresis molecules, which strongly inhibit the growth of ice crystals, are typically present (27,28). Interestingly, these molecules have so far not been detected in the small permeable soil invertebrates we are concerned with here, despite a number of attempts to find them (11,26,29). Because these animals equilibrate their body-fluid MP to their surroundings, ice crystal formation is impossible and thermal hysteresis molecules an unnecessary adaptation.…”

Section: Discussionmentioning

confidence: 89%

“…Because most soil invertebrates are unable to survive ice formation within their tissues (4)(5)(6)(7)(8)(9), the majority of studies of overwintering physiology in this group have been concerned with measurements of supercooling points, under the assumption that freeze avoidance by supercooling is the relevant adaptation to low-temperature survival. In small soil invertebrates with high integumental water permeability (e.g., enchytraeids, nematodes, and euedaphic Collembola), which completely dominate arctic and subarctic soil ecosystems (10), reported supercooling abilities (typically between Ϫ5 and Ϫ12°C) (6,8,(11)(12)(13)(14) are inadequate to explain winter survival. Recently, a third and fundamentally different strategy has been proposed for these animals.…”

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confidence: 99%

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Supercool or dehydrate? An experimental analysis of overwintering strategies in small permeable arctic invertebrates

Holmstrup

Bayley

Ramløv

2002

Proc. Natl. Acad. Sci. U.S.A.

168

118

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Soil invertebrate survival in freezing temperatures has generally been considered in the light of the physiological adaptations seen in surface living insects. These adaptations, notably the ability to supercool, have evolved in concert with surface invertebrates' ability to retain body water in a dry environment. However, most soil invertebrates are orders of magnitude less resistant to desiccation than these truly terrestrial insects, opening the possibility that the mechanisms involved in their cold-hardiness are also of a radically different nature. Permeable soil invertebrates dehydrate when exposed in frozen soil. This dehydration occurs because the water vapor pressure of supercooled water is higher than that of ice at the same temperature. The force of this vapor pressure difference is so large that even a few degrees of supercooling will result in substantial water loss, continuing until the vapor pressure of body fluids equals that of the surrounding ice. At this stage, the risk of tissue ice formation has been eliminated, and subzero survival is ensured. Here we show that these soil invertebrates do not base their winter survival on supercooling, as do many other ectotherms, but instead dehydrate and equilibrate their body-fluid melting point to the ambient temperature. They can achieve this equilibration even at the extreme cooling rates seen in polar soils.

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Section: Discussionmentioning

confidence: 89%

mentioning

confidence: 99%

Supercool or dehydrate? An experimental analysis of overwintering strategies in small permeable arctic invertebrates

Holmstrup

Bayley

Ramløv

2002

Proc. Natl. Acad. Sci. U.S.A.

168

118

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“…Aunaas et al (1983) investigated physiological aspects of various Svalbard invertebrates including determining the supercooling points of summer animals. The available literature on cold tolerance of North American and European species generally indicates relatively limited tolerance of sub-zero temperatures (e.g.…”

Section: Discussionmentioning

confidence: 99%

Survival of rapidly fluctuating natural low winter temperatures by High Arctic soil invertebrates

Convey

Abbandonato

Bergan

et al. 2015

Journal of Thermal Biology

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The extreme polar environment creates challenges for the resident invertebrate communities and the stress tolerance of some of these animals has been examined over many years. However, although it is well appreciated that standard air temperature records often fail to describe accurately conditions experienced at microhabitat level, few studies have explicitly set out to link field conditions experienced by natural multispecies communities with the more detailed laboratory ecophysiological studies of a small number of 'representative' species. This is particularly the case during winter, when snow cover may insulate terrestrial habitats from 3 extreme air temperature fluctuations. Further, climate projections suggest large changes in precipitation will occur in the polar regions, with the greatest changes expected during the winter period and, hence, implications for the insulation of overwintering microhabitats. To assess survival of natural High Arctic soil invertebrate communities contained in soil and vegetation cores to natural winter temperature variations, the overwintering temperatures they experienced were manipulated by deploying cores in locations with varying snow accumulation: No Snow, Shallow Snow (30cm) and Deep Snow (120cm). Air temperatures during the winter period fluctuated frequently between +3 and -24°C, and the No Snow soil temperatures reflected this variation closely, with the extreme minimum being slightly lower. Under 30cm of snow, soil temperatures varied less and did not decrease below -12°C. Those under deep snow were even more stable and did not decline below -2°C. Despite these striking differences in winter thermal regimes, there were no clear differences in survival of the invertebrate fauna between treatments, including oribatid, prostigmatid and mesostigmatid mites, Araneae, Collembola, Nematocera larvae or Coleoptera. This indicates widespread tolerance, previously undocumented for the Araneae, Nematocera or Coleoptera, of both direct exposure to at least -24°C and the rapid and large temperature fluctuations. These results suggest that the studied polar soil invertebrate community may be robust to at least one important predicted consequence of projected climate change.

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“…quenseli beetles was measured with Engelmann constant pressure respirometers as described by Aunaas et al (1983). The oxygen consumption of the other species, which were considerably smaller than the A .…”

Section: Methodsmentioning

confidence: 99%

“…The physiological adaptations in terrestrial invertebrates have been given only little attention by investigators. Aunaas et al (1983) investigated several species of insects and arachnids from Spitsbergen, and found that the Spitsbergen arthropods have metabolic rates higher than those of animals from other regions. However, in spite of the prevailing low summer temperatures, the animals displayed few adaptations to cold.…”

mentioning

confidence: 99%