Sexual reproduction and physiology of the soft coral Sclerophytum eilatenis along depth

The ability of species to thrive across environmental gradients relies on their ability for sexual reproduction and physiological adaptations to varying conditions. Advances in diving technologies have enabled in-depth research into corals ecology and biology along depth gradients, from shallow-water habitats to mesophotic coral ecosystems (MCEs; 30-150 m). Findings from such studies suggest that MCEs may act as refugia for some species, providing shelter from threats such as global climate change and local stressors. However, effective refugia necessitate that individuals within a population can both reproduce sexually and adapt physiologically along their depth range. This study investigates the reproductive biology and physiological traits of the zooxanthellate octocoral Sclerophytum eilatenis along a depth gradient in the Gulf of Aqaba/Eilat. By examining sexual reproduction characteristics and the physiological parameters of both host and symbiont, this study provides a comprehensive view into this octocoral’s adaptive nature. The current study’s findings indicate that MCEs may serve as reproductive refugia for S. eilatenis, offering favorable conditions for sexual reproduction. However, significant variations in reproductive and physiological characteristics along depth underscore the necessity for careful evaluation of the potential for MCEs to assist in the recovery of shallow reef populations. This study highlights the importance of integrating reproduction and physiological data in order to advance our understanding of coral adaptation and resilience in dynamic marine environments.