Some ecophysiological responses to osmoregulatory stress in selected aquatic amphipods with special reference to Gammarus duebeni
Some ecophysiological responses to osmoregulatory stress in selected aquatic amphipods with special reference to Gammarus duebeni
Aspects of the ecophysiology of Gammarus duebeni and related amphipods were investigated. Some species were found to be capable of rapid alteration in apparent water permeability. This is likely to be of considerable benefit during periods of osmotic stress. Measurements of water permeability in a range of acclimation salinities indicated that exclusion of amphipods from certain habitats can occur due to an inability to sufficiently restrict water fluxes. The apparent water permeability of G.duebeni is affected by the temperature as well as the salinity of the medium. A rise in temperature, and/or in salinity will increase the apparent water permeability of this species. The relative water fluxes through the gills and the general body surface is related to the habitat preferences of the amphipods. The more euryhaline a species is the greater the proportionate water flux through the gills. Interestingly the gills of the amphipods appear to be the site of rapid alteration in apparent water permeability. The composition of the epicuticular hydrocarbons influence general body permeability. Species inhabiting the least saline media had the greatest proportions of long chain unbranched hydrocarbons. Consideration is given to the mechanisms by which both long and short term changes in apparent water permeability might occur, and any adaptive value they could have.
The euryhaline amphipods investigated have the capacity to alter the sodium influx rate. Both G.duebeni and C.marinus can complete adjustments to the sodium influx within 5 hours. The enzyme responsible for this appears to be gill Na.K.ATPase. Heavy metal pollutants such as copper, lead and zinc as well as lipophillic pollutants (eg DDT) reduce the in vitro activity of this enzyme. The relevance of these findings to osmoregulation is considered.
G.duebeni is capable of detecting the salinity of the medium. This capability is necessary to ensure that suitable body fluid osmolarity is maintained. Processes by which this occurs were investigated using the selective metabolic poisons amiloride, colchicine, diamox, ouabaine and theo-phylline.
University of Southampton
1989
Lloyd Mills, Christopher
(1989)
Some ecophysiological responses to osmoregulatory stress in selected aquatic amphipods with special reference to Gammarus duebeni.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Aspects of the ecophysiology of Gammarus duebeni and related amphipods were investigated. Some species were found to be capable of rapid alteration in apparent water permeability. This is likely to be of considerable benefit during periods of osmotic stress. Measurements of water permeability in a range of acclimation salinities indicated that exclusion of amphipods from certain habitats can occur due to an inability to sufficiently restrict water fluxes. The apparent water permeability of G.duebeni is affected by the temperature as well as the salinity of the medium. A rise in temperature, and/or in salinity will increase the apparent water permeability of this species. The relative water fluxes through the gills and the general body surface is related to the habitat preferences of the amphipods. The more euryhaline a species is the greater the proportionate water flux through the gills. Interestingly the gills of the amphipods appear to be the site of rapid alteration in apparent water permeability. The composition of the epicuticular hydrocarbons influence general body permeability. Species inhabiting the least saline media had the greatest proportions of long chain unbranched hydrocarbons. Consideration is given to the mechanisms by which both long and short term changes in apparent water permeability might occur, and any adaptive value they could have.
The euryhaline amphipods investigated have the capacity to alter the sodium influx rate. Both G.duebeni and C.marinus can complete adjustments to the sodium influx within 5 hours. The enzyme responsible for this appears to be gill Na.K.ATPase. Heavy metal pollutants such as copper, lead and zinc as well as lipophillic pollutants (eg DDT) reduce the in vitro activity of this enzyme. The relevance of these findings to osmoregulation is considered.
G.duebeni is capable of detecting the salinity of the medium. This capability is necessary to ensure that suitable body fluid osmolarity is maintained. Processes by which this occurs were investigated using the selective metabolic poisons amiloride, colchicine, diamox, ouabaine and theo-phylline.
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Published date: 1989
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Local EPrints ID: 462670
URI: http://eprints.soton.ac.uk/id/eprint/462670
PURE UUID: 95a87d7a-d1a7-4fa2-93ae-67bf0c5277e1
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Date deposited: 04 Jul 2022 19:39
Last modified: 04 Jul 2022 19:39
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Author:
Christopher Lloyd Mills
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