Phosphorus Accelerate the Sulfur Cycle by Promoting the Release of Malodorous Volatile Organic Sulfur Compounds from Microcystis in Freshwater Lakes

Volatile organic sulfur compounds (VSCs) released by algae are of great significance in sulfur cycle, climate regulation and biological information transmission, and they are also the main compounds causing the taste and odor of freshwater. However, most of the previous studies focused on these compounds in the ocean, and little is known about the species of VSCs, algal source, and environmental regulatory factors in freshwaters. Here, we show that a variety of VSCs (mainly thioethers with small molecular weight, such as Dimethyl sulfide, DMS) could be released from freshwater algae by the cultivation of eight common Microcystis . Microcystis elabens , Microcystis panniformis , Microcystis flos-aquae and Microcystis aeruginosa , which bloom in freshwaters over the world, were found to be the main producers of VSCs. We also found that phosphorus (P) elevated the release of DMS by promoting the biomass and DMS yields of Microcystis . And similar results were also found in 16 field lakes at three different spatiotemporal scales. Overall, we revealed that the common freshwater Microcystis were able to release diverse thioethers, and the major VSCs were significantly influenced by water P concentrations. In the context of global freshwater eutrophication and Microcystis bloom, freshwater cyanobacteria driven S cycle and water odor will probably be further strengthened