Transepithelial potential in the Magadi tilapia, a fish living in extreme alkalinity

• Published in: Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology Biochemical, systemic, and environmental physiology, 2012-02, Vol.182 (2), p.247-258
• Main Authors: Wood, Chris M., Bergman, Harold L., Bianchini, Adalto, Laurent, Pierre, Maina, John, Johannsson, Ora E., Bianchini, Lucas F., Chevalier, Claudine, Kavembe, Geraldine D., Papah, Michael B., Ojoo, Rodi O.
• Format: Article
• Language: English
• Subjects: Adaptation, Biological - physiology; Alcolapia grahami; Alkalinity; Analysis of Variance; Animal Physiology; Animals; Anions; Biochemistry; Biomedical and Life Sciences; Biomedicine; Cichlidae; Electrochemistry; Environment; Extreme cold; Fish; Fisheries; Freshwater; Human Physiology; Hydrogen-Ion Concentration; Kenya; Lakes - chemistry; Life Sciences; Membrane Potentials - physiology; Models, Biological; Nitrates - metabolism; Original Paper; Permeability; Physiology; Sodium Bicarbonate - metabolism; Sodium chloride; Sodium Chloride - metabolism; Temperature; Tilapia; Tilapia - physiology; Zoology
• ISSN: 0174-1578; 1432-136X
• DOI: 10.1007/s00360-011-0614-y

We investigated the transepithelial potential (TEP) and its responses to changes in the external medium in Alcolapia grahami , a small cichlid fish living in Lake Magadi, Kenya. Magadi water is extremely alkaline (pH = 9.92) and otherwise unusual: titratable alkalinity (290 mequiv L −1 , i.e. HCO 3 − and CO 3 2− ) rather than Cl − (112 mmol L −1 ) represents the major anion matching Na +  = 356 mmol L −1 , with very low concentrations of Ca 2+ and Mg 2+ (