title: Ventilation and oxygen extraction in the little penguin (Eudyptula minor), at different temperatures in air and water.
abstract: Oxygen consumption, (VO2), carbon dioxide production (VCO2) and ventilation were measured in little penguins (Eudyptula minor) in air and water over a range of ambient temperatures. Barometrically measured minimum ventilation was very low (112 +/- 23 ml.min-1 over the range 15-20 degrees C, n = 9), principally due to a lower than predicted respiratory frequency (f) (6.9 +/- 1.1 min-1). This low ventilation resulted in a very high oxygen extraction (EO2) and low air convection requirement (VI/VO2). Despite large increases in metabolic rate in birds in cold water, VI/VO2 and hence EO2 did not vary in non-heat exposed penguins over a range of air and water temperatures. Mean extraction was 53.2 +/- 10.8% (n = 82) corresponding to an air convection requirement of 11.3 +/- 2.5 L.L-1. Above thermoneutrality there was a dramatic increase in ventilation and fall in EO2 resulting from increases in both f and tidal volume (VT). End-expired gases were measured at thermoneutrality and during heat exposure. At thermoneutrality FE'CO2 was 0.074 +/- 0.005, and FE'O2 0.115 +/- 0.009. During heat exposure end expired gases approached atmospheric levels.
authors: Department of Physiology, University of Tasmania, Hobart, Australia.
authors: C D
authors: CD
authors: Stahel
authors: S C
authors: SC
authors: Nicol
mesh_terms: D000818:Animals; D001717:Birds / Q000378:metabolism / Q000502:physiology*; D003080:Cold Temperature; D006358:Hot Temperature; D010101:Oxygen Consumption; D012119:Respiration; D013648:Tasmania; D013696:Temperature