C / N ratios in Pacific deep-sea sediments: Effect of inorganic ammonium and organic nitrogen compounds sorbed by clays
Abstract
Analyses of organic carbon, total nitrogen, and inorganically bound ammonium (exchangeable and fixed ammonium) in two oxic deep-sea sediment cores from the Central Pacific Ocean revealed insufficiently high inorganic ammonium contents of these sediments to explain the low C/N ratios, although representing 20-45% of the total nitrogen. Both, organic carbon/total nitrogen ratios (ranging from 3.9-1.3) and organic carbon/organic nitrogen ratios (5.6-1.9) decrease with increasing sediment depth, the latter indicating a real enrichment of organic nitrogen compounds during diagenesis relative to total organic matter. Organic matter/alumina relationships indicate that this unusual preservation of organic nitrogen compounds is probably caused by sorption to clay minerals protecting them against bacterial attack.
- Publication:
-
Geochimica et Cosmochimica Acta
- Pub Date:
- June 1977
- DOI:
- 10.1016/0016-7037(77)90047-3
- Bibcode:
- 1977GeCoA..41..765M