Coral reefs are constructed by calcifying coral animals that engage in a symbiosis with dinoflagellate microalgae harboured in their tissue. The symbiosis takes place in the presence of steep and dynamic gradients of light, temperature and chemical species that are affected by the structural and optical properties of the coral and their interaction with incident irradiance and water flow. Microenvironmental analyses have enabled quantification of such gradients and bulk coral tissue and skeleton optical properties, but the multi-layered nature of corals and its implications for the optical, thermal and chemical microenvironment remains to be studied in more detail. Here, we present a multiphysics modelling approach, where three-dimensional Monte Carlo simulations of the light field in a simple coral slab morphology with multiple tissue layers were used as input for modelling the heat dissipation and photosynthetic oxygen production driven by photon absorption. By coupling photon, heat and mass transfer, the model predicts light, temperature and O₂ gradients in the coral tissue and skeleton, under environmental conditions simulating, for example, tissue contraction/expansion, symbiont loss via coral bleaching or different distributions of coral host pigments. The model reveals basic structure–function mechanisms that shape the microenvironment and ecophysiology of the coral symbiosis in response to environmental change.

珊瑚礁是由钙化珊瑚动物构成的，这些珊瑚动物与它们组织中的甲藻微藻共生。共生发生在光、温度和化学物质的陡峭和动态梯度的存在下，这些梯度受到珊瑚的结构和光学特性及其与入射辐照度和水流的相互作用的影响。微环境分析已经能够量化这种梯度和大块珊瑚组织和骨骼的光学特性，但珊瑚的多层性质及其对光学、热和化学微环境的影响仍有待更详细地研究。在这里，我们提出了一种多物理场建模方法，其中具有多个组织层的简单珊瑚板形态中光场的三维蒙特卡罗模拟被用作模拟光子吸收驱动的散热和光合氧气产生的输入。通过耦合光子、热量和质量传递，该模型预测光、温度和 O₂珊瑚组织和骨骼中的梯度，在模拟环境条件下，例如，组织收缩/扩张、珊瑚白化导致的共生体损失或珊瑚宿主色素的不同分布。该模型揭示了响应环境变化而塑造珊瑚共生的微环境和生态生理的基本结构-功能机制。