The role of environmental factors and habitat on morphological plasticity of the seagrass-dwelling sponge Haliclona implexiformis in the Southern Gulf of Mexico

This study examined spatial and temporal variation in the morphology of the sponge Haliclona implexiformis inhabiting Thalassia testudinum meadows in the southern Gulf of Mexico. Environmental parameters and seagrass characteristics were analyzed across three sites and two seasons (dry and rainy) to evaluate their influence on sponge morphology. Results showed significant spatial differences among sites, while no consistent seasonal effects were detected. Monthly variability was significant but without a clear pattern across sites. Sponges from the most hydrodynamic site were smaller and exhibited larger oscular diameters, whereas those from more sheltered sites were larger and more branched. Hydrodynamism, organic matter content, and the proportion of coarse sediment particles (mollusk debris) were the factors most strongly associated with morphological variation. Although seagrass attributes, including leaf density and length, did not exhibit a direct correlation with sponge morphology, they may indirectly influence sponge form by altering sedimentation dynamics and local hydrodynamic conditions. Despite the proximity of the study site to an urban area, no anthropogenic influence was detected. The phenotypic plasticity of H. implexiformis appears to facilitate its establishment and persistence in seagrass meadows, conferring resilience to environmental variability and enabling morphological adjustments that optimize survival under changing conditions.