Lakes worldwide are changing and under threat due to stressors such as overload of nutrients, increased input of organic carbon (“browning”), and climate change, which may cause reduced water volume, salinization, or even loss of waterbodies. Some of these changes are abrupt to the extent that they can be characterized as tipping points for that particular system. Such changes may also cause increased release of greenhouse gases, and lakes are major players in the global climate in this context.

In this paper, greenhouse gas emissions due to peat oxidation were calculated for four different policy scenario's and with four different calculation methods in two polders of the Water Authority Amstel, Gooi and Vecht (the Netherlands). Outcomes depend on calculation methods and assumptions made. The scenario subsurface irrigation by submerged drains lead to lowest greenhouse gas emissions in this study (it was assumed that subsurface irrigation halves soil subsidence).

The differential effects of the aquatic plants on greenhouse gas fluxes may be due to plant density and whether or not the plant roots can access the sediment. We therefore looked into the effect of these two variables on water hyacinth greenhouse gas balance using a laboratory experiment. We found that greenhouse gas dynamics were strongly influenced by plant density and rooting. Our findings pinpoint management options that can optimize carbon sequestration and minimize CH₄ emissions.

Hydroelectric reservoirs in the tropics emit greenhouse gases but also bury carbon in their sediments. We investigated the efficiency of organic carbon (OC) burial in a large tropical reservoir, using spatially resolved measurements of sediment accumulation, and found that more than half (~ 57 %) of the OC deposited onto the sediment is buried. This high efficiency in OC burial indicates that tropical reservoirs may bury OC more efficiently than natural lakes.