title: Assimilation of benzene carbon through multiple trophic levels traced by different stable isotope probing methodologies.
abstract: The flow of benzene carbon along a food chain consisting of bacteria and eukaryotes, including larvae (Diptera: Chironomidae), was evaluated by total lipid fatty acids (TLFAs)-, amino acid- and protein-stable isotope probing (SIP). A coconut-fibre textile, colonized by a benzene-degrading biofilm, was sampled in a system established for the remediation of benzene, toluene, ethylbenzene and xylenes (BTEX)-polluted groundwater and incubated with (12)C- and [(13)C(6)]-benzene (>99 at.%) in a batch-scale experiment for 2-8 days. After 8 days, Chironomus sp. larvae were added to study carbon flow to higher trophic levels. Gas chromatography-combustion-isotope ratio monitoring mass spectrometry of TLFA showed increased isotope ratios in the (13)C-benzene-incubated biofilm. A higher (13)C-enrichment was observed in TLFAs, indicative of Gram-negative bacteria than for Gram-positive. Fatty acid indicators of eukaryotes showed significant (13)C-incorporation, but to a lower extent than bacterial indicators. Fatty acids extracted from larvae feeding on (13)C-biofilm reached an isotopic ratio of 1.55 at.%, illustrating that the larvae feed, to some extent, on labelled biomass. No (13)C-incorporation was detectable in larval proteins after their separation by sodium-dodecyl sulphate-polyacrylamide gel electrophoresis and analysis by nano-liquid-chromatography-mass spectrometry. The flow of benzene-derived carbon could be traced in a food web consisting of bacteria and eukaryotes.
authors.affiliation: Department of Isotope Biogeochemistry, UFZ-Helmholtz Centre for Environmental Research, Leipzig, Germany. fbastida@cebas.csic.es
authors.forename: Felipe
authors.initials: F
authors.lastname: Bastida
authors.forename: Sven
authors.initials: S
authors.lastname: Jechalke
authors.forename: Petra
authors.initials: P
authors.lastname: Bombach
authors.forename: Alessandro G
authors.initials: AG
authors.lastname: Franchini
authors.forename: Jana
authors.initials: J
authors.lastname: Seifert
authors.forename: Martin
authors.initials: M
authors.lastname: von Bergen
authors.forename: Carsten
authors.initials: C
authors.lastname: Vogt
authors.forename: Hans H
authors.initials: HH
authors.lastname: Richnow
mesh_terms: D000818:Animals; D001554:Benzene / Q000378:metabolism*; D001555:Benzene Derivatives / Q000378:metabolism; D018441:Biofilms; D002244:Carbon / Q000378:metabolism*; D002247:Carbon Isotopes / Q000032:analysis; D002683:Chironomidae / Q000254:growth & development / Q000378:metabolism*; D002853:Chromatography, Liquid; D005227:Fatty Acids / Q000032:analysis*; D020387:Food Chain; D006090:Gram-Negative Bacteria / Q000254:growth & development / Q000378:metabolism*; D019476:Insect Proteins / Q000032:analysis; D007814:Larva / Q000378:metabolism; D053719:Tandem Mass Spectrometry; D014050:Toluene / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000378:metabolism
chemical_list: D001555:Benzene Derivatives; D002247:Carbon Isotopes; D005227:Fatty Acids; D019476:Insect Proteins; D014874:Water Pollutants, Chemical; D014050:Toluene; D002244:Carbon; D001554:Benzene; C004912:ethylbenzene