title: Post-dive blood lactate concentrations in emperor penguins, Aptenodytes forsteri.
abstract: In order to determine an aerobic diving limit (ADL) in emperor penguins (Aptenodytes forsteri), post-dive blood lactate concentrations were measured in penguins foraging at an isolated sea ice hole. Resting lactate concentrations were 1.2-2.7 mmol l-1. Serial samples revealed that lactate level usually peaked within 5 min after dives and that 7-12 min was required for lactate concentrations to decrease from 5-8 mmol l-1 to less than 2.5 mmol l-1. Post-dive lactate level was not elevated above 3 mmol l-1 for dives shorter than 5 min. Two-phase regression analysis revealed a transaction at 5.6 min in the post-dive lactate level versus diving duration relationship. All dives longer than 7 min were associated with lactate concentrations greater than 5 mmol l-1. We conclude that the ADL in emperor penguins ranges between 5 and 7 min. These are the first determinations of post-dive lactate concentrations in any free-diving bird and are currently the only physiological assessment of an ADL in an avian species.
authors.affiliation: Scripps Institution of Oceanography, University of California, San Diego, La Jolla 92093-0204, USA. PPonganis@UCSD.edu
authors.forename: P J
authors.initials: PJ
authors.lastname: Ponganis
authors.forename: G L
authors.initials: GL
authors.lastname: Kooyman
authors.forename: L N
authors.initials: LN
authors.lastname: Starke
authors.forename: C A
authors.initials: CA
authors.lastname: Kooyman
authors.forename: T G
authors.initials: TG
authors.lastname: Kooyman
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D001717:Birds / Q000502:physiology*; D004242:Diving / Q000502:physiology*; D019344:Lactic Acid / Q000097:blood*
chemical_list: D019344:Lactic Acid