The ecophysiology of under-ice fauna
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...
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Norwegian Polar Institute
1991
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ftjpolarres:oai:journals.openacademia.net:article/2320 2023-05-15T16:19:33+02:00 The ecophysiology of under-ice fauna Aarset, Arne V. 1991-01-09 application/pdf https://polarresearch.net/index.php/polar/article/view/2320 https://doi.org/10.3402/polar.v10i1.6749 eng eng Norwegian Polar Institute https://polarresearch.net/index.php/polar/article/view/2320/5570 https://polarresearch.net/index.php/polar/article/view/2320 doi:10.3402/polar.v10i1.6749 Copyright (c) 2018 Polar Research Polar Research; Vol. 10 No. 1: Special issue: Proceedings of the Pro Mare Symposium on Polar Marine Ecology. Part 1; 309-324 1751-8369 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 1991 ftjpolarres https://doi.org/10.3402/polar.v10i1.6749 2021-11-11T19:12:32Z 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, O. glacialis and Apherusa glacialis were exposed to dilute seawater, elevated rates of oxygen consumption and ammonia excretion were observed. The O: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+4 and Na+. An increased rate of oxygen consumption, ammonia excretion and 0:N ratio versus temperature was observed for all species. Article in Journal/Newspaper Gammarus wilkitzkii Polar Research Polar Research (E-Journal) Polar Research 10 1 309 324 |
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Polar Research (E-Journal) |
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ftjpolarres |
language |
English |
description |
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, O. glacialis and Apherusa glacialis were exposed to dilute seawater, elevated rates of oxygen consumption and ammonia excretion were observed. The O: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+4 and Na+. An increased rate of oxygen consumption, ammonia excretion and 0:N ratio versus temperature was observed for all species. |
format |
Article in Journal/Newspaper |
author |
Aarset, Arne V. |
spellingShingle |
Aarset, Arne V. The ecophysiology of under-ice fauna |
author_facet |
Aarset, Arne V. |
author_sort |
Aarset, Arne V. |
title |
The ecophysiology of under-ice fauna |
title_short |
The ecophysiology of under-ice fauna |
title_full |
The ecophysiology of under-ice fauna |
title_fullStr |
The ecophysiology of under-ice fauna |
title_full_unstemmed |
The ecophysiology of under-ice fauna |
title_sort |
ecophysiology of under-ice fauna |
publisher |
Norwegian Polar Institute |
publishDate |
1991 |
url |
https://polarresearch.net/index.php/polar/article/view/2320 https://doi.org/10.3402/polar.v10i1.6749 |
genre |
Gammarus wilkitzkii Polar Research |
genre_facet |
Gammarus wilkitzkii Polar Research |
op_source |
Polar Research; Vol. 10 No. 1: Special issue: Proceedings of the Pro Mare Symposium on Polar Marine Ecology. Part 1; 309-324 1751-8369 |
op_relation |
https://polarresearch.net/index.php/polar/article/view/2320/5570 https://polarresearch.net/index.php/polar/article/view/2320 doi:10.3402/polar.v10i1.6749 |
op_rights |
Copyright (c) 2018 Polar Research |
op_doi |
https://doi.org/10.3402/polar.v10i1.6749 |
container_title |
Polar Research |
container_volume |
10 |
container_issue |
1 |
container_start_page |
309 |
op_container_end_page |
324 |
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1766005934308458496 |