Please use this identifier to cite or link to this item:
Title: Ion and acid-base balance in three species of Amazonian fish during gradual acidification of extremely soft water
Authors: Wilson, Rod W.
Wood, Chris M.
Gonzalez, Richard J.
Patrick, Marjorie L.
Bergman, Harold L.
Narahara, Annie B.
Val, Adalberto Luis
Keywords: Acidification
Acid Base Balance
Acid Rain
Ld 50
Water Pollution
Acid Rain
Acid-base Equilibrium
Adaptation, Physiological
Hydrogen-ion Concentration
Lethal Dose 50
Water Pollution
Issue Date: 1999
metadata.dc.publisher.journal: Physiological and Biochemical Zoology
metadata.dc.relation.ispartof: Volume 72, Número 3, Pags. 277-285
Abstract: Sensitivity to acid water was assessed in three species of Amazonian fish that encounter naturally acidic blackwaters to differing degrees in the wild: tambaqui (Colossoma macropomum), matrincha (Brycon erythropterum), and tamoata (Hoplosternum littorale), in decreasing order of occurrence in blackwater. Fish were exposed to a graded reduction in water pH, from pH 6 to 5 to 4 to 3.5, followed by return to pH 6. Fish were exposed to each new pH for 24 h. During these exposures, net transfers of ions (Na+, K+, Cl-, and Ca2+) and acid-base equivalents to and from the external water were used as physiological indicators of acid tolerance. Exposure to pH 5 had a minimal effect on net ion fluxes. Significant net losses of all ions (except Ca2+) were recorded in all three species during the first few hours of exposure to pH 4. However, ion balance was usually restored within 18 h at pH 4. Exposure to pH 3.5 caused even greater ion losses in all three species and proved to be acutely lethal to tamoata. Matrincha sustained irreversible physiological damage at pH 3.5, as ion fluxes did not recover following return to pH 6 and there was some mortality. Tambaqui suffered the least ionoregulatory disturbances at pH 3.5 and was the only species to make a full recovery on return to pH 6. In all species, there was a tendency for ammonia excretion to increase at low water pH, but even at pH 3.5, there was no significant net uptake of acid from the water. Overall, there was a strong relationship between the magnitude of ionic disturbances and the lethality of exposure to low pH. The relative insensitivity of the ionoregulatory system of tambaqui to low pH indicates that this is a feature of fish native to blackwater systems rather than one that is common to all Amazon fish.
metadata.dc.identifier.doi: 10.1086/316672
Appears in Collections:Artigos

Files in This Item:
There are no files associated with this item.

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.