Sample preparation and analysis for C content of wood and sediment
samples followed methodologies outlined by Tue et al. (2011). Briefly,
the wood and sediment samples were completely dried at 60°C in a
drying oven, and subsequently pulverized using an agate mortar and
pestle. For sediment organic C analysis, the pulverized sediments were
first treated with acid HCl 1N for 24 h to remove carbonates. After acid
treatment, the samples were thoroughly rinsed by Milli-Q filtered
distilled-deionized water and re-dried at 60 °C in a drying oven for
24 h. The C content of the sediment and wood samples was analyzed
by acombustion method using an elementanalyzer connected to an
isotope ratio mass spectrometer