Elemental analyses of total sulphur (S) and total carbon (C) were conducted with a Vario Micro Cube combustion elemental analyser (Elementar, Germany) was quantified on parallel samples with a DIMATOC 200 (DIMATEC Corp.).Stable isotope analysis δ13C ratios and the C/N concentrations were determined on freeze-dried sediment samples decarbonized 5% HCl. δ13C analyses were performed by combustion in a Costech ECS4010 Elemental Analyser (EA) on-line coupled to a VG TripleTrap (plus secondary cryogenic trap) and Optima dual-inlet mass spectrometer. δ13C values were calculated to the VPDB scale using a within-run laboratory standard (BROC2) calibrated against NBS 19 and NBS 22. Replicate analysis indicated precision of <0.1‰ (1 SD).