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首页> 外文期刊>The Journal of Experimental Biology >Mechanical versus physiological determinants of swimming speeds in diving bruennich's guillemots
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Mechanical versus physiological determinants of swimming speeds in diving bruennich's guillemots

机译：潜水布鲁尼奇海雀科动物游泳速度的机械因素与生理因素

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For fast flapping flight of birds in air, the maximum power and efficiency of the muscles occur over a limited range of contraction speeds and loads. Thus, contraction frequency and work per stroke tend to stay constant for a given species. In birds such as auks (Alcidae) that fly both in air and under water, wingbeat frequencies in water are far lower than in air, and it is unclear to what extent contraction frequency and work per stroke are conserved. During descent, compression of air spaces dramatically lowers buoyant resistance, so that maintaining a constant contraction frequency and work per stroke should result in an increased swimming speed. However, increasing speed causes exponential increases in drag, thereby reducing mechanical versus muscle efficiency. To investigate these competing factors, we have developed a biomechanical model of diving by guillemots (Uria spp.). The model predicted swimming speeds if stroke rate and work per stroke stay constant despite changing buoyancy. We compared predicted speeds with those of a free-ranging Bruennich's guillemot (U. lomvia) fitted with a time/depth recorder. For descent, the model predicted that speed should gradually increase to an asymptote of 1.5-1.6 m s super(-1) at approximately 40 m depth. In contrast, the instrumented guillemot typically reached 1.5 m s super(-1) within 10 m of the water surface and maintained that speed throughout descent to 80m.
机译：为了使鸟类在空中快速拍打，在有限的收缩速度和负荷范围内，会产生最大的肌肉力量和效率。因此，对于给定的种类，收缩频率和每冲程的功往往保持恒定。在像auks（Alcidae）一样在空中和水下飞行的鸟类中，水中的拍打频率远低于空气，因此尚不清楚收缩频率和每冲程功的保持程度。在下降过程中，压缩空气空间会大大降低浮力，因此，保持恒定的收缩频率和每冲程功可以提高游泳速度。但是，增加速度会导致阻力成指数增加，从而降低机械效率与肌肉效率。为了研究这些竞争因素，我们开发了海雀科的潜鸟的生物力学模型（Uria spp。）。如果浮力发生变化，则如果冲程速率和每冲程功保持恒定，该模型将预测游泳速度。我们将预测的速度与装有时间/深度记录器的自由范围的布伦尼希（guenmot）的海雀科的鸟（U. lomvia）进行了比较。对于下降，模型预测速度应在大约40 m深度逐渐增加到1.5-1.6 m s super（-1）的渐近线。相比之下，带仪表的海雀科的鸟儿通常在水面10 m内达到1.5 m s super（-1），并在整个下降过程中保持该速度至80m。

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