title: Land-based salmon aquacultures change the quality and bacterial degradation of riverine dissolved organic matter.
abstract: Aquacultures are of great economic importance worldwide but pollute pristine headwater streams, lakes, and estuaries. However, there are no in-depth studies of the consequences of aquacultures on dissolved organic matter (DOM) composition and structure. We performed a detailed molecular level characterization of aquaculture DOM quality and its bacterial degradation using four salmon aquacultures in Chile. Fluorescence measurements, ultrahigh-resolution mass spectrometry, and nuclear magnetic resonance spectroscopy of the DOM revealed specific and extensive molecular alterations caused by aquacultures. Aquacultures released large quantities of readily bioavailable metabolites (primarily carbohydrates and peptides/proteins, and lipids), causing the organic matter downstream of all the investigated aquacultures to deviate strongly from the highly processed, polydisperse and molecularly heterogeneous DOM found in pristine rivers. However, the upstream individual catchment DOM signatures remained distinguishable at the downstream sites. The benthic algal biovolume decreased and the bacterial biovolume and production increased downstream of the aquacultures, shifting stream ecosystems to a more heterotrophic state and thus impairing the ecosystem health. The bacterial DOM degradation rates explain the attenuation of aquaculture DOM within the subsequent stream reaches. This knowledge may aid the development of improved waste processing facilities and may help to define emission thresholds to protect sensitive stream ecosystems.
authors.affiliation: Helmholtz-Centre for Environmental Research UFZ, Department of River Ecology, Brückstraße 3a, D-39114 Magdeburg, Germany.|Helmholtz-Centre for Environmental Research UFZ, Department of Lake Research, Brückstraße 3a, D-39114 Magdeburg, Germany.
authors.forename: Norbert
authors.initials: N
authors.lastname: Kamjunke
authors.affiliation: Universidad Austral de Chile, Facultad de Ciencias, Instituto de Ciencias Marinas y Limnológicas, Laboratorio de Bioensayos y Limnologia Aplicada, Casilla 567, Valdivia, Chile.
authors.forename: Jorge
authors.initials: J
authors.lastname: Nimptsch
authors.affiliation: Helmholtz-Centre Munich, German Research Center for Environmental Health, Department of Environmental Sciences, Ingolstädter Landstraße 1, P. O. Box 1129, D-85758 Neuherberg, Germany.
authors.forename: Mourad
authors.initials: M
authors.lastname: Harir
authors.affiliation: Helmholtz-Centre for Environmental Research UFZ, Department of Lake Research, Brückstraße 3a, D-39114 Magdeburg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Herzsprung
authors.affiliation: Helmholtz-Centre Munich, German Research Center for Environmental Health, Department of Environmental Sciences, Ingolstädter Landstraße 1, P. O. Box 1129, D-85758 Neuherberg, Germany.
authors.forename: Philippe
authors.initials: P
authors.lastname: Schmitt-Kopplin
authors.affiliation: Helmholtz-Centre for Environmental Research UFZ, Department of River Ecology, Brückstraße 3a, D-39114 Magdeburg, Germany.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Neu
authors.affiliation: Aarhus University, Department of Bioscience, Vejlsøvej 25, 8600 Silkeborg, Denmark.
authors.forename: Daniel
authors.initials: D
authors.lastname: Graeber
authors.affiliation: Universidad Austral de Chile, Facultad de Ciencias, Instituto de Ciencias Marinas y Limnológicas, Laboratorio de Bioensayos y Limnologia Aplicada, Casilla 567, Valdivia, Chile.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Osorio
authors.affiliation: Universidad Austral de Chile, Facultad de Ciencias, Instituto de Ciencias Marinas y Limnológicas, Laboratorio de Bioensayos y Limnologia Aplicada, Casilla 567, Valdivia, Chile.
authors.forename: Jose
authors.initials: J
authors.lastname: Valenzuela
authors.affiliation: Universidad Austral de Chile, Facultad de Ciencias, Instituto de Ciencias Marinas y Limnológicas, Laboratorio de Bioensayos y Limnologia Aplicada, Casilla 567, Valdivia, Chile.
authors.forename: Juan
authors.initials: J
authors.lastname: Carlos Reyes
authors.affiliation: Universidad Austral de Chile, Facultad de Ciencias, Instituto de Ciencias Marinas y Limnológicas, Laboratorio de Bioensayos y Limnologia Aplicada, Casilla 567, Valdivia, Chile.
authors.forename: Stefan
authors.initials: S
authors.lastname: Woelfl
authors.affiliation: Helmholtz-Centre Munich, German Research Center for Environmental Health, Department of Environmental Sciences, Ingolstädter Landstraße 1, P. O. Box 1129, D-85758 Neuherberg, Germany.
authors.forename: Norbert
authors.initials: N
authors.lastname: Hertkorn
mesh_terms: D000818:Animals; D017756:Aquaculture; D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D001711:Biotransformation; D002244:Carbon / Q000737:chemistry / Q000378:metabolism; D017753:Ecosystem; D004784:Environmental Monitoring; D009682:Magnetic Resonance Spectroscopy; D064307:Microbiota; D009930:Organic Chemicals / Q000737:chemistry / Q000378:metabolism*; D045483:Rivers; D012474:Salmon; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D009930:Organic Chemicals; D002244:Carbon