Cervical air sac oxygen profiles in diving emperor penguins: parabronchial ventilation and the respiratory oxygen store.
Cassondra L Williams, Max F Czapanskiy, Jason S John, Judy St Leger, Miriam Scadeng, Paul J Ponganis
Author Information
Cassondra L Williams: National Marine Mammal Foundation, 2240 Shelter Island Dr. #200, San Diego, CA 92106, USA cassondra.williams@nmmpfoundation.org. ORCID
Max F Czapanskiy: Hopkins Marine Station, Department of Biology, Stanford University, Pacific Grove, CA 93950, USA. ORCID
Jason S John: Center for Ocean Health, Long Marine Laboratory, University of California, Santa Cruz, 115 McAlister Way, Santa Cruz, CA 95060, USA.
Judy St Leger: Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093-0204, USA. ORCID
Miriam Scadeng: Department of Anatomy and Medical Imaging, Faculty of Health and Medical Sciences, University of Auckland, Auckland 1142, New Zealand. ORCID
Paul J Ponganis: Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093-0204, USA. ORCID
Some marine birds and mammals can perform dives of extraordinary duration and depth. Such dive performance is dependent on many factors, including total body oxygen (O) stores. For diving penguins, the respiratory system (air sacs and lungs) constitutes 30-50% of the total body O store. To better understand the role and mechanism of parabronchial ventilation and O utilization in penguins both on the surface and during the dive, we examined air sac partial pressures of O ( ) in emperor penguins () equipped with backpack recorders. Cervical air sac values at rest were lower than in other birds, while the cervical air sac to posterior thoracic air sac difference was larger. Pre-dive cervical air sac values were often greater than those at rest, but had a wide range and were not significantly different from those at rest. The maximum respiratory O store and total body O stores calculated with representative anterior and posterior air sac data did not differ from prior estimates. The mean calculated anterior air sac O depletion rate for dives up to 11 min was approximately one-tenth that of the posterior air sacs. Low cervical air sac values at rest may be secondary to a low ratio of parabronchial ventilation to parabronchial blood O extraction. During dives, overlap of simultaneously recorded cervical and posterior thoracic air sac profiles supported the concept of maintenance of parabronchial ventilation during a dive by air movement through the lungs.
