Empirical estimation of skin resistance to water loss in amphibians: agar evaluation as a non-resistance model to evaporation

Author(s)

Senzano, Luis M. ; Bovo, Rafael P. ; Andrade, Denis, V

• Document type: Journal article
• Source: Journal of Experimental Biology; v. 225, n. 15, p. 6-pg., 2022-08-01.

Abstract

Total resistance (r(t)) to evaporative water loss (EWL) in amphibians is given by the sum of the boundary layer (r(b)) and the skin resistance (r(s)). Thus, r(s) can be determined if the r(b) component is defined (r(s)=r(t)-r(b)). The use of agar models has become the standard technique to estimate r(b) under the assumption that the agar surface imposes no barrier to evaporation (r(s)=0). We evaluated this assumption by determining EWL rates and r(b) values from exposed surfaces of free water, a physiological solution mimicking the osmotic properties of a generalized amphibian, and agar gels prepared at various concentrations using either water or physiological solution as diluent. Water evaporation was affected by both the presence of solutes and agar concentration. Models prepared with agar at 5% concentration in water provided the most practical and appropriate proxy for the estimation of r(b). (AU)

• FAPESP's process: 13/04190-9 - Thermal physiology and water balance in anurans along an altitudinal gradient in the Atlantic Rainforest
• Grantee: Denis Otavio Vieira de Andrade
• Support Opportunities: Regular Research Grants
• FAPESP's process: 10/20061-6 - Thermal physiology and water balance at different altitudinal gradients in Atlantic rainforest anurans
• Grantee: Rafael Parelli Bovo
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 18/05839-2 - Anurans of the Atlantic Forest: incorporating ecophysiological information to evaluate contemporary patterns of habitat occupancy and forecast for a warmer future
• Grantee: Denis Otavio Vieira de Andrade
• Support Opportunities: Scholarships abroad - Research
• FAPESP's process: 19/04637-0 - Integrating biological information in models predicting climate change impacts on amphibians
• Grantee: Rafael Parelli Bovo
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• FAPESP's process: 14/05624-5 - Ecological physiology of amphibians: a modeling approach
• Grantee: Rafael Parelli Bovo
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 17/10338-0 - Integrating physiological, ecological and evolutionary processes for comprehension of populational and species' responses to environmental changes
• Grantee: Rafael Parelli Bovo
• Support Opportunities: Scholarships in Brazil - Post-Doctoral