van Dam R P, Ponganis P J, Ponganis K V, Levenson D H, Marshall G
Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California - San Diego, La Jolla 92093-0204, USA.
J Exp Biol. 2002 Dec;205(Pt 24):3769-74. doi: 10.1242/jeb.205.24.3769.
During diving, intermittent swim stroke patterns, ranging from burst/coast locomotion to prolonged gliding, represent potential energy conservation mechanisms that could extend the duration of aerobic metabolism and, hence, increase the aerobic dive limit (ADL, dive duration associated with onset of lactate accumulation). A 5.6 min ADL for emperor penguins had been previously determined with lactate measurements after dives of <50 m depth. In order to assess locomotory patterns during such dives, longitudinal acceleration was measured with an attached accelerometer in 44 dives of seven adult birds diving from an isolated dive hole in the sea ice of McMurdo Sound, Antarctica. Detection of wing strokes in processed accelerometer data was verified in selected birds with analysis of simultaneous Crittercam underwater video footage. Mean dive duration of birds equipped with the accelerometer and a time-depth recorder (TDR) was 5.7+/-2.2 min; 48% of these dives were greater than the measured 5.6 min ADL (ADL(M)). Highest stroke frequencies (0.92+/-0.31 Hz, N=981) occurred during the initial descent to 12 m depth. Swimming effort was reduced to a mean stroke frequency <0.70 Hz during other phases of the dive (while traveling below 12 m depth, during foraging ascents/descents to and from the sub-ice surface, and during final ascents to exit). The longest stroke interval (8.6 s) occurred during a feeding excursion to the undersurface of the ice. In dives >ADL(M), mean stroke frequency during travel segments was significantly less than that in dives <ADL(M) (P<0.05). Mean stroke frequency of the entire dive correlated inversely (P<0.05) with diving duration (r=-0.67) and with mean dive depth (r=-0.43). Emperor penguins did not exhibit any significant (>10 s) periods of prolonged gliding during these shallow (<60 m) foraging dives. However, a stroke/glide pattern was evident with more than 50% of strokes associated with a stroke interval >1.6 s, and with lower stroke frequency associated with increased dive duration.
在潜水过程中，间歇式游泳划水模式，从爆发式/滑行运动到长时间滑翔，代表了潜在的能量保存机制，这些机制可以延长有氧代谢的持续时间，从而提高有氧潜水极限（ADL，与乳酸积累开始相关的潜水持续时间）。此前通过对深度小于50米的潜水后的乳酸测量，已确定帝企鹅的有氧潜水极限为5.6分钟。为了评估此类潜水中的运动模式，在南极洲麦克默多湾海冰上一个孤立的潜水洞，对7只成年鸟类的44次潜水进行了测量，用附着的加速度计测量纵向加速度。通过对同步的Crittercam水下视频片段进行分析，在选定的鸟类中验证了处理后的加速度计数据中翅膀划水的检测。配备加速度计和时间深度记录器（TDR）的鸟类的平均潜水持续时间为5.7±2.2分钟；其中48%的潜水时间超过了测量的5.6分钟有氧潜水极限（ADL(M)）。最高划水频率（0.92±0.31赫兹，N = 981）出现在最初下潜至12米深度期间。在潜水的其他阶段（当在12米深度以下游动时、在往返冰下表面的觅食上升/下降期间以及在最终上升出水期间），游泳力度降低至平均划水频率小于0.70赫兹。最长的划水间隔（8.6秒）出现在一次到冰下表面的觅食行程中。在超过有氧潜水极限（ADL(M)）的潜水中，游动阶段的平均划水频率显著低于低于有氧潜水极限（ADL(M)）的潜水（P<0.05）。整个潜水的平均划水频率与潜水持续时间（r = -0.67）和平均潜水深度（r = -0.43）呈负相关（P<0.05）。在这些浅（<60米）觅食潜水中，帝企鹅没有表现出任何显著（>10秒）的长时间滑翔期。然而，一种划水/滑翔模式很明显，超过50%的划水与划水间隔>1.6秒相关，并且较低的划水频率与潜水持续时间增加相关。
