The death and subsequent decomposition of algal blooms is capable of depleting dissolved O-2 to anaerobic levels, and this can de-inactivate hydrogenases. Inspired by this fact, a simple method for efficient H-2 production from algal bloom biomass was developed. Direct transfer of Taihu Lake Microcystis spp. blooms into dark conditions resulted in H-2 evolution, and yield was much greater than compared to Microcystis spp. cultured in the laboratory and reported previously in the literature. Further, efficient H-2 production was inhibited significantly by light, which was most likely due to reduced O-2 content and the stimulation of hydrogenase activity. Therefore, a simple approach for efficient H-2 production from Taihu Lake Microcystis spp. blooms is presented. Furthermore, a post-treatment strategy for dealing with large quantities of refloated algal blooms is proposed. (C) 2013 Elsevier Ltd. All rights reserved.