This project experimentally quantifies species-specific thermal performance curves (TPCs) for dominant coral taxa collected from both upwelling and non-upwelling reef sites. Thermal performance is assessed using the photosynthesis-to-respiration (P:R) ratio measured across a controlled temperature gradient as a proxy for the coral holobiont’s thermal threshold. This approach tests whether chronic exposure to the naturally variable thermal regime of upwelling environments confers broader thermal performance breadth or enhanced thermal tolerance relative to non-upwelling conspecifics. To complement physiological measurements, high-resolution image analysis is performed on corals exposed to the thermal treatments to quantify tissue coloration changes as a visual indicator of coral health and stress. Additionally, chlorophyll concentration and symbiont (zooxanthellae) density are measured to assess photophysiological condition and bleaching-related responses across temperature treatments.