Free fatty acids in Lake Aydat catchment soils (French Massif Central): sources, distributions and potential use as sediment biomarkers

Abstract

International audiencePurpose: Eighteen soils were sampled in the Lake Aydat catchment in order to analyse free fatty acid (FA) content; FAs are considered to be among the most amenable biomarkers to mobilisation by runoff waters. The majority of the study area has soil cover consisting of grasslands or forest since the 2nd World War, although some covers having changed more recently. Material and methods: The soil studied all developed on volcanic rocks (andisols). The bulk organic matter (OM) content of the samples was characterized by Rock-Eval (RE) pyrolysis. The FAs were determined by gas chromatography-mass spectrometry (GC-MS) analysis of isolated and derivatized (methylation and trimethylsilylation) FA fractions. Results and discussion: Few low molecular weight compounds (LMW; i.e.

Preservation of an ancient grassland biomarker signature in a forest soil from the French Massif Central

“…a rather low degree of OM preservation. This is consistent with a previous analysis of this sample which revealed a high content of free fatty acids (FAs) indicative of a release of these compounds by hydrolysis of plant esters (Zocatelli et al, 2012). Comparison of Sf and Spf showed that the latter displayed a higher TOC value associated with a lower pH.…”

“…HI values of the sub-surface samples (2-4 cm) were similar to those of other samples from the catchment (Zocatelli et al, 2012), but were quite low when compared with the large soil sample set studied by Disnar et al (2003). However, as pointed out by the latter authors, HI values are largely dependent on local vegetation.…”

“…Sub-samples were dried at 40 °C over 48 h in an oven, crushed in a mortar and sieved at 2 mm. Zocatelli et al (2012), so only those relevant here are mentioned below.…”

Sedimentary evidence of soil organic matter input to the Curuai Amazonian floodplain

“…The standard was n° 160.000 (Vinci Technologies) and device precision was +/-3%. Details of the methodology of the temperature program have been described by Zocatelli et al (2012a Organic petrography extracts were prepared as described by Zocatelli et al (2012b).…”

Evolution of pastoralism in Southern Greenland during the last two millennia reconstructed from bile acids and coprophilous fungal spores in lacustrine sediments

“…DOC and other bile acids have been lar gely st udied in wat er , sewage and sur ficial est uar ine sediment s t o evaluat e faecal pollut ion and det er mine it s sour ce (Elhmmali et al, 1997;Bull et al, 2002;Tyagi et al, 2008). They have also been st udied in ant hr opogenic and past ur e soils (Zocat elli et al, 2012). Bile acids ar e spar sely r epor t ed, however , in ancient envir onment al samples and wer e det ect ed in ar chaeological cont ext s such as ant hr opogenic manur e palaeosoils (Bull et al, 1999) and Neolit hic copr olit es (Shillit o et al, 2011).…”