Dr John Milledge is a member of Algal Biotechnology Research Group at the University of Greenwich which he joined in 2013. He returned to research at the beginning of 2008 after a long spell in company management and has worked on several projects, both macro and microalgae, for Pure Energy Fuels and the Universities of Southampton & Greenwich. John’s current primary interest is in potential exploitation of the genus Sargassum for biofuel and other products. Sargassum is a broad genus or family of brown seaweed consisting of around 300 species. Sargassum muticum is an invasive species to the coasts of the British Isles. Holopelagic or floating Sargassum (S. natans and S. fluitans) in the open ocean, is a tremendous ecological and climate resource. However, enormous beach inundations, or golden tides, in the last ten years are causing economic and environmental challenges. Commercial exploration could encourage Sargassum harvesting and control. Macroalgae may be a potential source of fuel. However, practical yields of biogas from the anaerobic digestion of macroalgae are substantially below the theoretical maximum. Sargassum has a naturally high content of antioxidants, carotenoids, sulphated compounds, halogenated compounds and phenols, making this genus also a potential source of a range of pharmaceutically relevant materials. Can we change these golden tides into a golden opportunity?