title: Organic matter in sediment layers of an acidic mining lake as assessed by lipid analysis. Part II: Neutral lipids.
abstract: Natural neutralization of acidic mining lakes is often limited by organic matter. The knowledge of the sources and degradability of organic matter is crucial for understanding alkalinity generation in these lakes. Sediments collected at different depths (surface sediment layer from 0 to 1 cm and deep sediment layer from 4 to 5cm) from an acidic mining lake were studied in order to characterize sedimentary organic matter based on neutral signature markers. Samples were exhaustively extracted, subjected to pre-chromatographic derivatizations and analyzed by GC/MS. Herein, molecular distributions of diagnostic alkanes/alkenes, terpenes/terpenoids, polycyclic aromatic hydrocarbons, aliphatic alcohols and ketones, sterols, and hopanes/hopanoids were addressed. Characterization of the contribution of natural vs. anthropogenic sources to the sedimentary organic matter in these extreme environments was then possible based on these distributions. With the exception of polycyclic aromatic hydrocarbons, combined concentrations across all marker classes proved higher in the surface sediment layer as compared to those in the deep sediment layer. Alkane and aliphatic alcohol distributions pointed to predominantly allochthonous over autochthonous contribution to sedimentary organic matter. Sterol patterns were dominated by phytosterols of terrestrial plants including stigmasterol and β-sitosterol. Hopanoid markers with the ββ-biohopanoid "biological" configuration were more abundant in the surface sediment layer, which pointed to higher bacterial activity. The pattern of polycyclic aromatic hydrocarbons pointed to prevailing anthropogenic input. Pyrolytic makers were likely to due to atmospheric deposition from a nearby former coal combustion facility. The combined analysis of the array of biomarkers provided new insights into the sources and transformations of organic matter in lake sediments.
authors: Helmholtz Center for Environmental Research-UFZ, Department of Environmental Engineering, Permoserstr. 15, 04318 Leipzig, Germany. Electronic address: juergen.poerschmann@ufz.de.
authors: Juergen
authors: J
authors: Poerschmann
authors: Helmholtz Center for Environmental Research-UFZ, Department of Lake Research, Brueckstr. 3a, 39114 Magdeburg, Germany.
authors: Matthias
authors: M
authors: Koschorreck
authors: Department of Chemistry, University of Waterloo, 200 University Ave. W., Waterloo, ON, N2L 3G1, Canada.
authors: Tadeusz
authors: T
authors: Górecki
mesh_terms: D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry*; D005858:Germany; D060106:Lakes; D008055:Lipids / Q000032:analysis*; D008906:Mining; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D008055:Lipids; D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical
keywords: Acidic mining lake; Alkanols; Hydrocarbons; Sedimentary organic matter; Sterols