Stable C and N isotope determination of Suspended Particulate Matter (SPM)

Additionally, to trace the Suspended Particulate Matter (SPM) towards its origin, carbon (12C/13C) and nitrogen (14N/15N) stable isotope ratios will be measured, since organic matter from marine and terrestrial origin has a different isotopic C and sometimes N signature. Pre-baked glass fibre filters are used to collect SPM for C and N isotope analysis in the sampling sites. After the filters are dried, subsamples of the filters were then cut and left for 24 h in an acid fume chamber. Finally, the acidified samples are analysed by EA-IRMS (Elemental Analysis – Isotopic Ratio Mass Spectroscopy). At the end in combination with modelling techniques, mixing of water masses will be estimated.