Seaweeds are crucial primary producers in temperate costal systems throughout the world, supplying a range of ecosystem services to humans: they provide habitat and food for higher trophic levels, support productive finfish and shell-fish industries, protect coastlines from wave forces, and are critical for nitrogen and carbon cycling. However, seaweeds are highly sensitive to environmental change, particularly the ongoing rapid alterations to chemical and physical environmental divers due to human activity. Globally, oceans are warming with more frequent marine heat waves, becoming more acidic with less oxygen, along with changes to underwater light regime and nitrogen supply. These global changes occur together with local environmental changes including eutrophication due to altered land use practices (urbanization, deforestation), and pollution (e.g. heavy metals).
Predicting how seaweed communities, and the ecosystems they support, will be affected when multiple environmental drivers change simultaneously is a developing research field. In this presentation, I will outline new experimental approaches for assessing the impacts of multiple drivers on seaweeds, discuss how driver interactions can result in unexpected experimental outcomes, and consider how seaweed biodiversity might change in a future ocean.