Evidence of adaptive plasticity in the coral Echinopora spp. to different turbidity regimes

Turbid reefs, once seen as marginal, are now considered potential refuges for laminar-shaped corals under climate stress. This study examines micro-morphological plasticity in two foliose coral species: Echinopora lamellosa and E. pacificus, across turbid and non-turbid sites in East Lombok, Indonesia. A total of 137 specimens from different depths (2 m and 4 m) and turbidity levels were analysed using ten diagnostic morphological traits. Principal component analysis explained >97% of the total morphological variance and revealed clear differentiation by site and depth. E. pacificus showed complete separation between populations, while E. lamellosa displayed partial overlap—suggesting environmentally driven plasticity. Deep colonies in non-turbid sites resembled shallow colonies in turbid areas, supporting the idea of adaptive morphometric responses rather than fixed traits. Outgroup validation using a geographically distinct population of the same species confirmed the observed patterns, strengthening the evidence for environment-related variation. The patterns observed may involve phenotypic plasticity or epigenetic changes, which warrants further investigation. These findings highlight the plastic ability of foliose corals to exploit either shallow or turbid habitats through their diverse morphological traits, underscoring their resilience and potential significance for future reef conservation, restoration and management efforts amid turbidity-driven climate change.