Comeya peatland is located in Picos de Europa National Park (N. Spain) at 851 m above sea level, representing the continuous postglacial infill of a hollow (growth rate = 0.4 mm/yr) during the last 15,000 cal. yr BP. Three intervals can be distinguished in the profile: the bottom one, with ash content close to 90%, which is previous to the peatland installation in the area and is followed by an interval with oscillating ash content (30-60%) probably related to alluvial fan sedimentation. The uppermost one corresponds to the peat deposit with ash content generally close to 10%. The present day vegetation consists of Sphagnum species with herbaceous plants and heathers. The study comprises the analysis of some biomarkers with potential as palaeoenvironmental proxies quantified by gas chromatography/mass spectrometry, supported by bulk delta C-13 and delta N-15 isotopic. The biomarker assemblage is dominated by the n-alkanes and methyl-ketones with medium-to-high molecular weight and odd number of carbons. The biomarker ratios indicate an enrichment in Sphagnum characteristic compounds at 120-250 cm (3150-6350 cal. yr BP) reflecting more humid conditions. This episode coincides with higher C/N atomic ratio, higher values of delta C-13 and lower of delta N-15. The wetter conditions of this interval are also shown by the depleted 8D values of the n-alkane, particularly those related with mosses as (n-C-23 and n-C-25) and the enriched delta C-13 values of both n-alkanes and methyl-ketones. Segregation of delta C-13 values has been observed for homologues series in Comeya peat with medium molecular weight n-alkanes typical of mosses living in waterlogged environments, being enriched in delta C-13 values compared with higher molecular weight n-alkanes typical of woody and herbaceous plants of drier habitats. This study has shown a slight enrichment of delta C-13 values of methyl-ketones compared to n-alkanes, the differences being not conclusive to support a common or different origin for both compound classes. (C) 2016 Elsevier B.V. All rights reserved.