title: Off-site impacts of agricultural composting: role of terrestrially derived organic matter in structuring aquatic microbial communities and their metabolic potential.
abstract: While considered as sustainable and low-cost agricultural amendments, the impacts of organic fertilizers on downstream aquatic microbial communities remain poorly documented. We investigated the quantity and quality of the dissolved organic matter leaching from agricultural soil amended with compost, vermicompost or biochar and assessed their effects on lake microbial communities, in terms of viral and bacterial abundances, community structure and metabolic potential. The addition of compost and vermicompost significantly increased the amount of dissolved organic carbon in the leachate compared with soil alone. Leachates from these additions, either with or without biochar, were highly bioavailable to aquatic microbial communities, although reducing the metabolic potential of the community and harbouring more specific communities. Although not affecting bacterial richness or taxonomic distributions, the specific addition of biochar affected the original lake bacterial communities, resulting in a strongly different community. This could be partly explained by viral burst and converging bacterial abundances throughout the samples. These results underline the necessity to include off-site impacts of agricultural amendments when considering their cascading effect on downstream aquatic ecosystems.
authors.affiliation: UMR CNRS 5557, USC 1364 INRA, Ecologie Microbienne, Université Lyon1, Université de Lyon, Villeurbanne, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Pommier
authors.forename: Asmaa
authors.initials: A
authors.lastname: Merroune
authors.forename: Yvan
authors.initials: Y
authors.lastname: Bettarel
authors.forename: Patrice
authors.initials: P
authors.lastname: Got
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Janeau
authors.forename: Pascal
authors.initials: P
authors.lastname: Jouquet
authors.forename: Thuy D
authors.initials: TD
authors.lastname: Thu
authors.forename: Tran D
authors.initials: TD
authors.lastname: Toan
authors.forename: Emma
authors.initials: E
authors.lastname: Rochelle-Newall
mesh_terms: D000383:Agriculture; D059001:Aquatic Organisms / Q000187:drug effects*; D001419:Bacteria / Q000145:classification* / Q000187:drug effects / Q000235:genetics; D002606:Charcoal; D005308:Fertilizers / Q000009:adverse effects* / Q000032:analysis; D059013:Microbial Consortia / Q000187:drug effects*; D009930:Organic Chemicals / Q000009:adverse effects* / Q000032:analysis; D012987:Soil; D012988:Soil Microbiology; D014780:Viruses / Q000145:classification* / Q000187:drug effects / Q000235:genetics
chemical_list: D005308:Fertilizers; D009930:Organic Chemicals; D012987:Soil; C540010:biochar; D002606:Charcoal
keywords: lakes; metabolic potential; off-site effects; soil leachates