Centre for Ocean Life, National Institute of Aquatic Resources, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
Centre for Ocean Life, National Institute of Aquatic Resources, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
Proc Natl Acad Sci U S A. 2020 Dec 1;117(48):30101-30103. doi: 10.1073/pnas.2017441117. Epub 2020 Nov 16.
Many planktonic suspension feeders are attached to particles or tethered by gravity when feeding. It is commonly accepted that the feeding flows of tethered suspension feeders are stronger than those of their freely swimming counterparts. However, recent flow simulations indicate the opposite, and the cause of the opposing conclusions is not clear. To explore the effect of tethering on suspension feeding, we use a low-Reynolds-number flow model. We find that it is favorable to be freely swimming instead of tethered since the resulting feeding flow past the cell body is stronger, leading to a higher clearance rate. Our result underscores the significance of the near-field flow in shaping planktonic feeding modes, and it suggests that organisms tether for reasons that are not directly fluid dynamical (e.g., to stay near surfaces where the concentration of bacterial prey is high).
许多浮游悬浮生物在进食时附着在颗粒上或被重力束缚。人们普遍认为，被束缚的悬浮生物的摄食流比自由游动的悬浮生物更强。然而，最近的流动模拟表明情况恰恰相反，而导致这两种相反结论的原因尚不清楚。为了探究束缚对悬浮摄食的影响，我们使用了一个低雷诺数流动模型。我们发现，自由游动比被束缚更有利，因为流过细胞体的摄食流更强，从而导致更高的清除率。我们的结果强调了近场流动对塑造浮游摄食模式的重要性，并且表明生物被束缚的原因不是直接的流体力学因素（例如，为了停留在细菌猎物浓度高的表面附近）。
