title: Tracing biogeochemical and microbial variability over a complete oil sand mining and recultivation process.
abstract: Recultivation of disturbed oil sand mining areas is an issue of increasing importance. Nevertheless only little is known about the fate of organic matter, cell abundances and microbial community structures during oil sand processing, tailings management and initial soil development on reclamation sites. Thus the focus of this work is on biogeochemical changes of mined oil sands through the entire process chain until its use as substratum for newly developing soils on reclamation sites. Therefore, oil sand, mature fine tailings (MFTs) from tailings ponds and drying cells and tailings sand covered with peat-mineral mix (PMM) as part of land reclamation were analyzed. The sample set was selected to address the question whether changes in the above-mentioned biogeochemical parameters can be related to oil sand processing or biological processes and how these changes influence microbial activities and soil development. GC-MS analyses of oil-derived biomarkers reveal that these compounds remain unaffected by oil sand processing and biological activity. In contrast, changes in polycyclic aromatic hydrocarbon (PAH) abundance and pattern can be observed along the process chain. Especially naphthalenes, phenanthrenes and chrysenes are altered or absent on reclamation sites. Furthermore, root-bearing horizons on reclamation sites exhibit cell abundances at least ten times higher (10(8) to 10(9) cells g(-1)) than in oil sand and MFT samples (10(7) cells g(-1)) and show a higher diversity in their microbial community structure. Nitrate in the pore water and roots derived from the PMM seem to be the most important stimulants for microbial growth. The combined data show that the observed compositional changes are mostly related to biological activity and the addition of exogenous organic components (PMM), whereas oil extraction, tailings dewatering and compaction do not have significant influences on the evaluated compounds. Microbial community composition remains relatively stable through the entire process chain.
authors.affiliation: GFZ German Research Centre for Geosciences, Section 4.3 Organic Geochemistry, Telegrafenberg, 14473 Potsdam, Germany. Electronic address: noah@gfz-potsdam.de.
authors.forename: Mareike
authors.initials: M
authors.lastname: Noah
authors.affiliation: University of Potsdam, Institute of Earth and Environmental Science, Geomicrobiology Group, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Lappé
authors.affiliation: University of Potsdam, Institute of Earth and Environmental Science, Geomicrobiology Group, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany.
authors.forename: Beate
authors.initials: B
authors.lastname: Schneider
authors.affiliation: GFZ German Research Centre for Geosciences, Section 4.3 Organic Geochemistry, Telegrafenberg, 14473 Potsdam, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Vieth-Hillebrand
authors.affiliation: GFZ German Research Centre for Geosciences, Section 4.3 Organic Geochemistry, Telegrafenberg, 14473 Potsdam, Germany.
authors.forename: Heinz
authors.initials: H
authors.lastname: Wilkes
authors.affiliation: GFZ German Research Centre for Geosciences, Section 4.5 Geomicrobiology, Telegrafenberg, 14473 Potsdam, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Kallmeyer
mesh_terms: D007220:Industrial Waste / Q000032:analysis; D059013:Microbial Consortia; D008906:Mining; D061329:Oil and Gas Fields / Q000382:microbiology*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D007220:Industrial Waste; D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical
keywords: Biomarker; Microbial community analysis; Oil sands; PAH; Reclamation; Tailings ponds