Changes in seagrass leaf reddening and morphology in response to emersion

Abstract Intertidal seagrasses often cope with a complex combination of stresses during low tide, especially light, temperature, and desiccation, which influence seagrass survival mechanisms, consequently forming zonation patterns along the shore. To investigate whether seagrass pigment and leaf morphological characteristics change in response to emersion, we sampled three intertidal seagrass species (Halophila ovalis, Cymodocea rotundata, and Thalassia hemprichii) in Laem Yong Lam, Haad Chao Mai National Park, Trang, Thailand. Using transplantation methods across the upper and lower intertidal zones, where emersion times differ, we found that these three seagrass species have different adaptive strategies to grow under stresses in the intertidal zone. All three seagrass species responded to decreasing emersion times by decreasing leaf length and width. The leaf sheath of C. rotundata increased in length with decreasing emersion times. Our research provides a characterization of different seagrass strategies, which involve differential changes in leaf pigmentation and morphological adjustments to survive under stresses during emersion in the intertidal zone.