The osmoregulation of selected gammarid amphipods

Brooks, S.J., 2003. The osmoregulation of selected gammarid amphipods. PhD, Nottingham Trent University.

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The osmoregulation of gammarid amphipods from fresh, brackish and marine environments are investigated. Osmoregulation is determined from measurements of haemolymph ion concentration, half time of body water exchange (t1/2), sodium flux and gill Na+, K+-ATPase, with respect to salinity acclimation. The effect of rapid salinity change on t1/2 and sodium influx in some gammarids is also investigated. Gill Na+, K+-ATPase is characterised for the main ion and co-factor requirements in G. pulex. This transport enzyme is actively involved in the osmoregulation of all gammarids investigated, with enzyme activity strongly influenced by the salinity of the external medium.

The observed differences in the osmoregulatory physiology of gammarids are related to the adaptation of species to the ionic concentration of their natural habitat. The ability of freshwater adapted gammarids to maintain haemolymph ion concentrations significantly lower than more brackish water species provides them with an energetic advantage in dilute media. These differences in osmoregulation are suggested to influence competitive interactions between gammarids from Northern Ireland and The Netherlands.

Significant differences in t1/2 and sodium flux are found between the freshwater adapted G. duebeni celticus and the more brackish water form G. duebeni duebeni. Such differences are suggested to be due to the evolutionary adaptation of these isolated subspecies to their contrasting natural habitats. Furthermore, the effects of a number of stressors on the osmoregulatory physiology of the freshwater amphipod G. pulex are investigated. These stressors include: in vivo and in vitro copper exposure, parasite infection, and low energy cave environments. Significant effects of all these stressors on the osmoregulation of G. pulex are found and discussed in relation to the mechanisms of effect.

Item Type: Thesis
Creators: Brooks, S.J.
Date: 2003
ISBN: 9781369325898
Divisions: Schools > School of Science and Technology
Record created by: Laura Ward
Date Added: 12 Jul 2021 14:39
Last Modified: 22 May 2024 15:42

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