Effects of phytoplankton blooms on fluxes and emissions of greenhouse gases in a eutrophic lake

• Heatwaves and cyanobacterial blooms influenced greenhouse gases in a lake. Anoxia associated to heatwaves enhanced CH 4 effluxes by up 10 times. High were with CO 2 N O under-saturation at the surface. Cyanobacterial stimulated flux more than of other phytoplankton. Synergy between affects role lakes GHG budget. Lakes are important sources (GHGs) atmosphere. Factors controlling , fluxes include eutrophication warming, but integrated influence climate-warming-driven stratification, oxygen loss resultant changes bloom characteristics on GHGs not well understood. Here we assessed contrasting meteorological conditions stratification phytoplankton composition eutrophic lake, tested for inventories both shallow deep waters, over three seasons (2010-2012). Atmospheric had one most dramatic effects GHGs. Indeed, that developed response heatwave events 2012 sedimentary concentrations (reaching 1mM) emissions atmosphere (up 8 mmol m ?2 d ?1 ). That summer, contributed 52% warming potential produced lake (in equivalents) as compared 34 39% years without blooms. accumulation subsequent emission preceded consumption surface (uptakes -30 -1.6 µmol respectively). Fall overturn presented large efflux particularly from littoral zone after bloom. We provide evidence that, despite cooling observed depth during hot summers, increased via stronger resulting biomass deposition intensified bottom water anoxia. Our results, supported recent literature reports, suggests novel interplay climate change hydrodynamics impacts production lakes. Given global trends enrichment, these interactive should be considered accurately predict future emissions.