Mechanical Stimuli Enhance the Growth of Ulva fasciata (Chlorophyta) Spores

Abstract

The macroalgal forest is being transformed to barren ground in coastal areas due to climate change. Current recovery technologies are ineffective, and an understanding of the fouling mechanism of macroalgae would assist restoration of macroalgal forests. Here, it is attempted to promote the growth of Ulva fasciata spores using an artificial biofilm composed of alginate and silica particles (the most abundant polymers and inorganics in marine biofilms) by mimicking marine environments. The presence of silica particles in the artificial biofilm increased the average germling length of Ulva spores, suggesting that mechanical stimuli generated by the silica particles enhanced growth of Ulva spores. As the stiffness of the model substrates (polystyrene, hydrophilic silica, hydrophobic silica, PDMS) increased, the germling length of the spores increased irrespective of surface chemistry and hydrophobicity. These results suggest that manipulation of the mechanical stimuli generated by the substrate could enable control of macroalgal fouling.