The effect of external flow on the feeding currents of sessile microorganisms
The effect of external flow on the feeding currents of sessile microorganisms
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DOI：
10.1098/rsif.2020.0953
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发表时间：
2021-02
影响因子：
3.9
通讯作者：
Rachel E. Pepper;E. E. Riley-E.;Matthieu Baron;Thomas Hurot;L. Nielsen;M. Koehl;T. Kiørboe;A. Andersen
中科院分区：
文献类型：
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作者：
Rachel E. Pepper;E. E. Riley-E.;Matthieu Baron;Thomas Hurot;L. Nielsen;M. Koehl;T. Kiørboe;A. Andersen
微型无柄悬浮捕食者生活附着在表面，通过消耗细菌大小的猎物和被消耗，他们形成了水生生态系统的重要组成部分。它们对环境的影响是由它们的摄食率介导的，这取决于自生的摄食电流。摄食率已被假设为是有限的再循环涡流，导致生物体饲料从水是耗尽的食物颗粒。然而，这些结果考虑了静水中的生物，而环境流通常存在于其自然栖息地中。我们表明，使用一个点力模型，即使是非常缓慢的环境流量，速度几个数量级小于自生的喂养电流，是足以破坏周围的垂直悬浮馈线的漩涡，提供一个恒定的供应食物丰富的水。然而，在外部流中，由于形成了静水中看不到的再循环结构，在非垂直方向的范围内，进料速率降低。我们量化的喂养流量，并观察这种再循环实验的悬浮饲料Vorticella convallaria在外部流典型的溪流和河流。
Microscopic sessile suspension feeders live attached to surfaces and, by consuming bacteria-sized prey and by being consumed, they form an important part of aquatic ecosystems. Their environmental impact is mediated by their feeding rate, which depends on a self-generated feeding current. The feeding rate has been hypothesized to be limited by recirculating eddies that cause the organisms to feed from water that is depleted of food particles. However, those results considered organisms in still water, while ambient flow is often present in their natural habitats. We show, using a point-force model, that even very slow ambient flow, with speed several orders of magnitude less than that of the self-generated feeding current, is sufficient to disrupt the eddies around perpendicular suspension feeders, providing a constant supply of food-rich water. However, the feeding rate decreases in external flow at a range of non-perpendicular orientations due to the formation of recirculation structures not seen in still water. We quantify the feeding flow and observe such recirculation experimentally for the suspension feeder Vorticella convallaria in external flows typical of streams and rivers.