Synergistic alleviation of lake eutrophication and carbon emission by macrophyte restoration.

Algal blooms induced by eutrophication not only deteriorate water quality but also enhance greenhouse gas emissions. Although the theory of multiple stable states suggests that macrophyte restoration can reverse phytoplankton domination in lakes, associated ecosystem climate benefits are rarely considered. Based on a recent mass balance model, we highlight macrophyte restoration as a promising strategy to synergistically alleviate lake eutrophication and carbon emissions. We found a general decrease in net carbon dioxide equivalents (ΔCO2-eq) after macrophyte restoration, and then we discussed the potential pathways by which macrophyte restoration decreases carbon emissions. It is also noteworthy that such net climate benefits are much more dependent on the applied restoration species and ecosystem management via associated trade-offs between CO2 sequestration and methane (CH4) emissions. Our study emphasizes the significance of macrophyte restoration for its important roles in enhancing water quality and carbon sink in lakes.