"Enrichment of 15N in total nitrogen in the water body [particulate >unknown phase] by centrifugation, combustion and mass spectrometry"@en . . . "PONd15N" . "D15NMTPC" . "30-JUN-14" . "2" . "D15NMTPC" . "D15NMTPC" . "Mass spectrometry on combusted sample (centrifuged)" . "2" . "accepted" .