| one publication added to basket [59504] | Acid-base homeostasis in aquatic animals exposed to natural and perturbed environments
Truchot, J.-P. (1993). Acid-base homeostasis in aquatic animals exposed to natural and perturbed environments. Belg. J. Zool. 123(Suppl. 1): 73
In: Belgian Journal of Zoology. Koninklijke Belgische Vereniging voor Dierkunde = Société royale zoologique de Belgique: Gent. ISSN 0777-6276; e-ISSN 2295-0451, more
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| Keywords |
Fauna > Aquatic organisms > Aquatic animals
Pollutants
Marine/Coastal; Fresh water |
| Abstract |
Keeping an appropriate acid-base state in the various body compartments of animals is of prime importance for many basic living processes, especially those depending on protein conformation and electric charge, which are in large part determined by the pH. Acid-base homeostasis requires a balance between metabolic production and controlled excretion of two categories of acids and bases: the volatile carbonic acid whose the elimination depends on respiratory regulations, and fixed acids and bases, the excretion of which is usually associated with ion exchanges. In aquatic animals, these functions are heavily challenged by large natural changes of respiratory gases, oxygen and carbon dioxide, as well as of particular ions or total salinity in the environment. The effects of each of these factors in isolation have been well studied in laboratory conditions, but integrated responses to the changes of many factors as it occurs in the natural setting are less well known. Variations of ambient or internal CO2 are not a strong stimulus to breathing in aquatic crustaceans and fishes, and respiratory regulations are thus of little importance in acid-base homeostasis. On the contrary, aquatic organisms are usually able to quickly get rid of large fixed acid or alkaline loads by coupling their excretion with gillionic exchanges. Such excretory process also serve to compensate acid-base disturbances induced by changes of the respiratory qualities of the water. The well-known impact of various pollutants on gill ionoregulatory mechanisms (heavy metals, ammonia, acid waters...) can also considerably disturb the acid-base balance in aquatic animals. Selected examples will be presented to illustrate and discuss these various aspects of acid-base homeostasis in crustaceans and fishes living in freshwater as well as in seawater. |
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