Thermoregulation, gas exchange, and ventilation

• Main Authors: Physiology B %~"~o' O, Sherrie L. Souza
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1987
• Subjects: Pygoscelis adeliae
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.210.6352; http://www.biology.ucr.edu/people/faculty/MACpubs/PDFfiles/JCPBadelievent.pdf

Summary. Adelie penguins (Pygoscelis adeliae) experience a wide range of ambient temperatures (T,) in their natural habitat. We examined body temperature (Tb), oxygen consumption (l)o~), carbon dioxide production (V co2), evaporative water loss (rhH2o), and ventilation at T ~ from--20 to 30 ~ Body temperature did not change significantly be-tween-20 and 20 ~ (mean Tb=39.3 ~ Tb increased slightly to 40.1 ~ at Ta = 30 ~ Both l)o~ and l/co2 were constant and minimal at Ta between-10 and 20 ~ with only minor increases at-20 and 30 ~ The minimal 1/o2 of adult penguins (mean mass 4.007kg) was 0.0112ml/[g-min], equivalent to a metabolic heat production (MHP) of 14.9 Watt. The respiratory exchange ratio was approximately 0.7 at all Ta. Values of rhn2o were low at low T~, but increased to 0.21 g/rain at 30 ~ equivalent to 0.3 % of body mass/h. Dry conductance increased 3.5-fold between-20 and 30 ~ Evaporative heat loss (EHL) comprised about 5% of MHP at low Ta, rising to 47 % of MHP at Ta = 30 ~ The means of ventilation parameters (tidal volume [VT], respiration frequency [f], minute volume [l/I], and oxygen extraction leon]) were fairly stable between-20 and 10 ~ (VT did not change significantly over the entire Ta range). However, there was considerable inter- and intra-individual variation in ventilation patterns. At Ta = 20-30 ~ f increased 7-fold over the minimal value of 7.6 breaths/rain, and 1~I showed a similar change. Eo ~ fell from 28-35 % at low Ta to 6 % at Ta= 30 ~ Abbreviations: C thermal conductance; EHL evaporative heat loss; Eo2 oxygen extraction;frespiratory frequency; MHP metabolic heat production; rh~i~o evaporative water loss; LCT lower critical temperature; RE respiratory exchange ratio; T. ambient temperature; Tb body temperature; 1/o2 rate of oxygen consumption; l)co2 rate of carbon dioxide production; l? ~ inspiratory minute volume; VT tidal volume