Adaptive feeding is a strategy used by many organisms to maintain growth and reproduction success while encountering varying feeding conditions. Oysters are sessile benthic and non‐siphon filter feeders. Oysters are well adapted to modify the ambient microenvironment through their pumping behavior and particle selection activity. Rejection of unsuitable food particulates bound in pseudofeces via ejection events are an integral part of oyster feeding during which oysters produced strong flow opposite to their inhalant feeding flow. The strong opposite pulsatile flow during the ejection event inevitably disrupts the oyster's normal feeding cycle, but how oysters restart their feeding and allocate their energy consumption during an ejection event has not been investigated. The present study used particle image velocimetry (PIV) to examine the impact of ejection events on the feeding of the American oyster, Crassostrea virginica. The strong pulsatile flow resulting from pseudofecal ejection altered the external flow fields by moving water away from the shell. The initial feeding zone after pseudofecal ejection was relatively narrow, possessed a low pulsatile flow, and did not exploit the full flow field. The feeding zone gradually expanded as the pulsatile flow weakened. The strong shear rate at the stable feeding zone then sustained the feeding flow that facilitated oyster feeding. Furthermore, the volumetric fluxes often increased after the ejection event, suggesting increase in feeding efficiency after ejection events. These PIV studies provide new insight on the interactions between feeding oysters and the surrounding physical environment at small yet ecologically relevant scales.

中文翻译：

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美国牡蛎Crassostrea virginica的自适应饲喂：假粪便抛射过程中脉动血流的复杂影响

适应性饲养是许多生物体在遇到变化的饲养条件时维持生长和繁殖成功的一种策略。牡蛎是无底栖和非虹吸滤食器。牡蛎非常适合通过其泵送行为和颗粒选择活性来改变周围的微环境。通过排泄事件来排泄假粪便中结合的不合适的食物颗粒是牡蛎摄食不可或缺的部分，在此期间牡蛎产生了与其吸入食流相反的强流。排出事件期间强烈的相反脉动流不可避免地破坏了牡蛎的正常进食周期，但是牡蛎如何在排出事件期间重新开始进食并分配能量消耗。Crassostrea virginica。伪粪便喷射产生的强烈脉动流通过将水从壳中移出而改变了外部流场。伪粪便弹射后的初始进食区相对较窄，搏动血流较低，并且没有充分利用流场。随着脉动流减弱，进食区逐渐扩大。稳定进食区的强剪切速率继而维持了促进牡蛎进食的进料流。此外，在排出事件之后，体积通量经常增加，表明在排出事件之后进给效率增加。这些PIV研究在较小但与生态相关的规模上提供了牡蛎摄食与周围自然环境之间相互作用的新见解。