[Tidal fDOM and Heterotrophic bacteria counts] - fDOM and Heterotrophic bacteria counts in Oregon tide pools in July - August 2019 (CAREER: Predicting ecosystem metabolism of rocky intertidal communities in warming and acidifying oceans.)

Yet, the role of benthic biological processes in shaping pelagic microbial dynamics remains under explored. We investigated how surfgrass and mussels regulate nitrogen and dissolved organic matter (DOM)cycling and their cascading effects on heterotrophic bacteria in Oregon tide pools.

We quantified biogeochemical fluxes and bacterial responses before and after foundation species removal during contrasting upwelling regimes. Mussel-dominated pools released high concentrations of ammonium and nitrate, while surfgrass pools transformed DOM that fueled bacterial growth; upwelling intensified these benthic–pelagic linkages. Removing foundation species dampened nutrient release in mussel pools and reduced DOM-fueled bacterial growth in surfgrass pools, ultimately decoupling benthic productivity from pelagic microbial growth.