Croll D A, McLaren E
Physiological Research Laboratory, Scripps Institution of Oceanography, La Jolla, CA 92093.
J Comp Physiol B. 1993;163(2):160-6. doi: 10.1007/BF00263602.
The diving and thermoregulatory metabolic rates of two species of diving seabird, common (Uria aalge) and thick-billed murres (U. lomvia), were studied in the laboratory. Post-absorptive resting metabolic rates were similar in both species, averaging 7.8 W.kg-1, and were not different in air or water (15-20 degrees C). These values were 1.5-2 times higher than values predicted from published allometric equations. Feeding led to increases of 36 and 49%, diving caused increases of 82 and 140%, and preening led to increases of 107 and 196% above measured resting metabolic rates in common and thick-billed murres, respectively. Metabolic rates of both species increased linearly with decreasing water temperature; lower critical temperature was 15 degrees C in common murres and 16 degrees C in thick-billed murres. Conductance (assuming a constant body temperature) did not change with decreasing temperature, and was calculated at 3.59 W.m-2 x degrees C-1 and 4.68 W.m-2 x degrees C-1 in common and thick-billed murres, respectively. Murres spend a considerable amount of time in cold water which poses a significant thermal challenge to these relatively small seabirds. If thermal conductance does not change with decreasing water temperature, murres most likely rely upon increasing metabolism to maintain body temperature. The birds probably employ activities such as preening, diving, or food-induced thermogenesis to meet this challenge.
在实验室中研究了两种潜水海鸟，即普通海鸦（海鸦属）和厚嘴海鸦的潜水及体温调节代谢率。两种海鸦的吸收后静息代谢率相似，平均为7.8瓦·千克⁻¹，在空气或水中（15 - 20摄氏度）并无差异。这些数值比根据已发表的异速生长方程预测的值高1.5至2倍。进食分别使普通海鸦和厚嘴海鸦的代谢率比测得的静息代谢率提高了36%和49%，潜水使其提高了82%和140%，梳理羽毛则使其分别提高了107%和196%。两种海鸦的代谢率均随水温降低呈线性增加；普通海鸦的较低临界温度为15摄氏度，厚嘴海鸦为16摄氏度。传导率（假设体温恒定）不随温度降低而变化，普通海鸦和厚嘴海鸦的传导率分别计算为3.59瓦·米⁻²·摄氏度⁻¹和4.68瓦·米⁻²·摄氏度⁻¹。海鸦在冷水中度过大量时间，这对这些相对较小的海鸟构成了重大的热挑战。如果传导率不随水温降低而变化，海鸦很可能依靠提高代谢率来维持体温。这些鸟类可能利用梳理羽毛、潜水或食物诱导的产热等活动来应对这一挑战。
