Occurrence of long-chain acyclic methyl ketones in Sphagnum and Carex peats of various degress of humification

Biomarkers and inorganic proxies in the paleoenvironmental reconstruction of mires: The importance of landscape in Las Conchas (Asturias, Northern Spain)

“…Moreover, C 23 has been reported to be the most abundant alkan-2-one in Zoige-Hongyuan peat bog in West China (Zheng et al, 2007). A similar predominance of LMW alkan-2-ones as that found in the mire has been reported in other Asturian mires (López-Días et al, 2010a;Arboleya, 2011;López-Días et al, 2013a;Ortiz et al, 2010), including the nearby Roñanzas peat bog (only 1 km from Las Conchas), in the region of Galicia , the Hani peat bog in northeastern China (Zheng et al, 2011) and mires in Sweden (Lehtonen and Ketola, 1990), in which the shorter chain C 17 -C 23 homologs greatly increased in abundance with increasing humification.…”

“…Thus, long chain alkan-2-ones have other possible sources, including microbial oxidation of the corresponding n-alkanes (Ambles et al, 1993;van Bergen et al, 1998) and microbial~-oxidation and decarboxylation of FAs (Püttmann and Bracke, 1995), especially in peatlands, in which microbial activity can be significant (d. Lehtonen and Ketola, 1990;Zheng et al, 2007). On the basis of the higher 8 13 C values of n-alkane-2-ones compared with n-alkanes, López-Días et al (2013b) suggested that bacterial activity could be a greater contributor of alkan-2-ones to peat than the other two sources.…”

“…The n-alkane content and distribution have been used to discriminate between Sphagnum (moss) vs. Erica (heather) input and in turn to reconstruct paleoenvironmental conditions linked to humid or drier climatic phases (Nott et al, 2000;Pancost et al, 2002;McClymont et al, 2005;Nichols et al, 2006;Ortiz et al, 2010). n-Alkan-2-ones also occur in peat (Morrison and Bick, 1967;Lehtonen and Ketola, 1990;Xie et al, 2004;Nichols and Huang, 2007;Zheng et al, 2007;Ortiz et al, 2010;López-Días et al, 2013b). They may have diverse origins, including direct input from plants (Arpino et al, 1970;Volkman et al, 1981), microbial oxidation of n-alkanes (Cranwell et al, 1987;Ambles et al, 1993;Jaffé et al, 1993Jaffé et al, , 1996van Bergen et al, 1998), microbial~-oxidation and decarboxylation of fatty acids (FAs; Volkman et al, 1983;Chaffee et al, 1986;de Leeuw, 1986;Quénéa et al, 2004) and bacterial material (López-Días et al, 2013b).…”

n-Alkan-2-ones in peat-forming plants from the Roñanzas ombrotrophic bog (Asturias, northern Spain)

“…n-Alkan-2-ones also occur in peat (Morrison and Bick, 1967;Lehtonen and Ketola, 1990Xie et al, 2004Nichols and Huang, 2007;Zheng et al, 2007;Ortiz et al, 2010), but less is known about their significance. In addition to their direct provenance from plants (Arpiño et al, 1970;Volkman et al, 1981), long chain ketones may have other origins, including microbial oxidation of the corresponding n-alkanes (Cranwell et al, 1987;Ambles et al, 1993;Jaffé et al, 1993Jaffé et al, , 1996van Bergen et al, 1998) or microbial p-oxidation and decarboxylation of n-fatty acids (Volkman et al, 1983;Chaffee et al, 1986;de Leeuw, 1986;Quénéa et al, 2004).…”

Composition and sources of organic matter and its solvent extractable components in surface sediments of a bay under serious anthropogenic influences: Daya Bay, China

“…The distribution of n-ketones in different geological samples typically showed similar distributions with a high predominance of odd-over-even carbon number homologues with maxima at C 27 or C 29 (Hernandez et al, 2001;Tuo and Li, 2005). Some researchers proposed that the process of microbial oxidation of n-alkanes and b-oxidation of fatty acids followed by decarboxylation could produce n-alkane-2-ones (e.g., Allen et al, 1971;Volkman et al, 1981;Lehtonen and Ketola, 1990). Apart from natural sources, the anthropogenic discharge of cooking smoke, wood burning smoke, and automobile exhaust are also sources of n-alkan-2-ones (e.g., Simoneit, 1985;Standley and Simoneit, 1987;Rogge et al, 1991).…”