Effects of Temperature and pH on the Dynamics of Hemoglobin-Oxygen Binding Properties in Marine Mammals.

• Main Author: Stewart, Brent S.
• Other Authors: HUBBS-SEA WORLD RESEARCH INST SAN DIEGOCA
• Format: Text
• Language: English
• Published: 1999
• Subjects: Biochemistry; Biological Oceanography; *OXYGEN; *MARINE BIOLOGY; *HEMOGLOBIN; *DIVING; DYNAMICS; SATURATION; PH FACTOR; SEALS(MAMMALS); WHALES; BLOOD GASES; DOLPHINS(MAMMALS); PARTIAL PRESSURE; Pacific; Elephant Seals; Killer Whale; Killer whale
• Online Access: http://www.dtic.mil/docs/citations/ADA365184; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA365184

Nine species of marine mammals were evaluated to determine the intraspecific variation in the affinity of hemoglobin for oxygen under varying conditions of pH and temperature. A typical sigmoidal curve of oxygen saturation versus partial pressure of oxygen was found in all species under each condition tested. This curve was shifted to the right in pinnipeds (harbor seals, California sea lions, northern elephant seals) relative to cetaceans (common dolphin, Pacific white-sided dolphin, Commerson's dolphin, bottlenose dolphin, killer whale), indicating a lower affinity of hemoglobin for oxygen in the former. The affinity of hemoglobin for oxygen was greater in the smaller species of odontocete cetaceans (common dolphin, Commerson's's dolphin, Pacific white-sided dolphin). It increased substantially with temperature in sea lions and elephant seals but not in harbor seals or the cetaceans and decreased with decreasing pH (Bohr effect) in all species. Overall, the hemoglobin of phocid pinnipeds, which are known to be long and deep breath-hold divers, was generally lower than in the other species. These characteristics are evidently adaptations which promote the unloading of oxygen to the tissues at the end of a long dive, when oxygen stores are depleted, in the former species whereas they allow rapid loading of oxygen at the surface during the brief but frequent surface periods of the latter species.