Schematic overview of the GHG dynamic and C fluxes from aquatic ecosystems according to lake type (A) and potential short-term impact of FPV (B). A. Once in the sediment, the processing of organic matter produced CO₂ and CH₄ (1). Once produced, the oxidation of CH₄ to CO₂ by methanotrophs and the uptake of CO₂ by primary producers mitigate GHG emissions to the atmosphere (2,3). GHGs that escape oxidation and the carbon sink are emitted to the atmosphere by diffusing across the water-atmosphere interface (4). At shallow depth, CH₄ is transported from the sediment to the atmosphere through ebullition (5). During the ebullition process, there may be dissolution and oxidation of CH₄ into the water column (6). Vascular plants such as macrophytes act as important conduits for CH₄ to the atmosphere (7). Emergent aquatic insects, which spend their larval stages in lake sediments and emerge as adults, represent C fluxes from aquatic to terrestrial habitats, providing high quality resources for terrestrial consumers (8). B. Irrespective of lake type, the increased OM supply resulting from the death of primary producers in response to severe shading and from allochthonous inputs could fuel benthic respiration processes and thus GHG production. In particular, CH₄ production would increase, favoured by anoxic conditions in the sediments. At shallow depths, much of the CH₄ produced would be emitted to the atmosphere via ebullitive pathways. The GHG not emitted by ebullition would accumulate in the water column due to reduced CH₄ oxidation and CO₂ uptake by primary producers combined with reduced gas transfer velocities beneath the panels. For stratified lakes, high emissions could occur during mixing events, although though FPV would shorten stratification and reduce mixing depths. FPV would reduce insect larval biomass and ultimately adult emergence due to reduced DO, cooler temperature and loss of habitat complexity and trophic resources. Such effects on C fluxes would increase in magnitude with panel coverage, especially in shallow and small lakes, due to higher primary and secondary production prior to FPV implementation.