biostudies-literatureStruik QMinistry of EducationEuropean Research CouncilDutch Research Council (NWO)Soehngen Institute of Anaerobic Microbiologyfiae061https://www.ebi.ac.uk/biostudies/studies/S-EPMC11075768biostudies-literatureUnknown100(5)Aquatic ecosystems are large contributors to global methane (CH4) emissions. Eutrophication significantly enhances CH4-production as it stimulates methanogenesis. Mitigation measures aimed at reducing eutrophication, such as the addition of metal salts to immobilize phosphate (PO43-), are now common practice. However, the effects of such remedies on methanogenic and methanotrophic communities-and therefore on CH4-cycling-remain largely unexplored. Here, we demonstrate that Fe(II)Cl2 addition, used as PO43- binder, differentially affected microbial CH4 cycling-processes in field experiments and batch incubations. In the field experiments, carried out in enclosures in a eutrophic pond, Fe(II)Cl2 application lowered in-situ CH4 emissions by lowering net CH4-production, while sediment aerobic FEMS microbiology ecologyFe(II)Cl2 amendment suppresses pond methane emissions by stimulating iron-dependent anaerobic oxidation of methane.PMC11075768854008818661024002002Rios-Miguel ABGlodowska MMeulepas BMJWVeraart AJJetten MSMStruik QParanaiba JRNijman TPAKosten SLurling MWaajen GfalseFe(II)Cl2 amendment suppresses pond methane emissions by stimulating iron-dependent anaerobic oxidation of methane.Aquatic ecosystems are large contributors to global methane (CH4) emissions. Eutrophication significantly enhances CH4-production as it stimulates methanogenesis. Mitigation measures aimed at reducing eutrophication, such as the addition of metal salts to immobilize phosphate (PO43-), are now common practice. However, the effects of such remedies on methanogenic and methanotrophic communities-and therefore on CH4-cycling-remain largely unexplored. Here, we demonstrate that Fe(II)Cl2 addition, used as PO43- binder, differentially affected microbial CH4 cycling-processes in field experiments and batch incubations. In the field experiments, carried out in enclosures in a eutrophic pond, Fe(II)Cl2 application lowered in-situ CH4 emissions by lowering net CH4-production, while sediment aerobic 2024-01-01T00:00:00Z2024 Apr2026-06-01T17:26:33.2Z2026-04-08T14:13:06.71ZS-EPMC110757683863204010.1093/femsec/fiae061