Seagrasses form one of the most productive coastal habitats that provide high-value ecosystem services, and yet are faced with global decline due to increasing anthropogenic stressors. I am currently asking how these threatened ecosystems may respond to future ocean acidification (OA), which is an ongoing decrease in ocean pH through absorption of increasing atmospheric CO2. Recently, increasing number of studies has begun to investigate seagrass responses to OA. However, a majority of these studies has tested only for direct effects of OA, while potential indirect effects that could be mediated by other environmental or ecological factors remain largely unexplored. Therefore, my study aims to incorporate both direct and indirect effects of ocean acidification to more realistically predict the consequences for global seagrass ecosystems.
I am particularly focusing on how mutualistic and competitive interactions in seagrass beds might mediate the effect of OA on seagrass performances. Seagrasses are ubiquitously associated with invertebrate grazer communities that control epiphytic algae competing with seagrass for resources. I am investigating the extent to which grazer-controls of epiphytes can be altered under different pH conditions, and how this may feed back into seagrass performances. For this, I have been conducting a series of pH manipulation experiments under mesocosm settings with surfgrass Phyllospadix spp., ubiquitous foundation species along the California coast. I am also taking advantage of natural pH gradients that are found in CO2 vents near the Island of Ischia (Italy) to perform field manipulative studies with Neptune grass Posidonia oceanica, which is a major conservation concern in Mediterranean.