Coelentera are the largest components by volume in the gastrovascular system connecting polyps in a scleractinian colony. Thus to understand colony connectivity which is predicted to affect corals response to environmental change, we must first describe the dynamics inside these gastric cavities of individual polyps. We determined key time scales of mixing in coelentera by using microelectrodes to measure oxygen concentration after a light-to-dark transition in three polyps each of three colonies of Montastraea cavernosa in the laboratory. The gastrovascular system was modeled as an electrical network where voltage represents oxygen concentration, current represents oxygen flux, capacitors represent volume compartments, and resistors represent impedance to oxygen flux. The time constant of mixing, defined as the time needed for the system to disperse 63.2% of the fluid in the coelenteron, was determined from the oxygen dynamics in the coelenteron as modeled by a resistor-capacitor network. Time constants were on the order of three minutes and oxygen dynamics were well fit by the model prediction. However, as polyps depleted oxygen, we observed small magnitude (~ 0.1 ppm), high-frequency fluctuations in oxygen concentration. A power spectral density analysis identified two time scales of high-frequency mixing in the coelenteron. The greatest variance occurred at a period of 48.3 ± 2.8 seconds, with a secondary peak seen at 35.9 ± 2.3 seconds. The microenvironment within polyps of M. cavernosa can respond as fast or faster than their external environment can fluctuate, thus scleractinian polyps have the capacity to mediate their response to changing environmental conditions.

中文翻译：

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无孔巩膜腔肠腔中混合的时间尺度

肠腔菌是连接巩膜息肉的息肉的胃血管系统中体积最大的成分。因此，要了解预计会影响珊瑚对环境变化的反应的殖民地连通性，我们必须首先描述单个息肉在这些胃腔内的动态。我们通过使用微电极测量Montastraea cavernosa的三个菌落的三个息肉从明暗过渡后的氧气浓度来确定腔肠动物中混合的关键时间尺度在实验室里。胃血管系统被建模为一个电网，其中电压代表氧气浓度，电流代表氧气通量，电容器代表容积隔室，电阻器代表对氧气通量的阻抗。混合的时间常数定义为系统将63.2％的流体分散在腔腔中所需的时间，该时间常数是通过腔腔中的氧气动力学（由电阻器-电容器网络建模）确定的。时间常数大约为三分钟，并且通过模型预测可以很好地拟合氧气动力学。但是，由于息肉耗尽了氧气，我们观察到氧气浓度的小幅度波动（〜0.1 ppm），高频波动。功率谱密度分析确定了腔肠管高频混合的两个时间尺度。最大的方差发生在48.3±2.8秒的时间段内，第二高峰出现在35.9±2.3秒的时间段。息肉内的微环境M.海绵体可以一样快或更快比它们的外部环境可以波动作出响应，从而造礁石息肉有调停他们不断变化的环境条件的反应的能力。