Prokopenko, Maria G.; Hammond, Douglas E.; Spivack, Arthur J.; Stott, Lowell (2006): Impact of long-term diagenesis on delta (super 15) N of organic matter in marine sediments; Sites 1227 and 1230. Texas A&M University, Ocean Drilling Program, College Station, TX, United States, In: Jorgensen, Bo B. (editor), D'Hondt, Steven L. (editor), Miller, D. Jay (editor), Aiello, Ivano W., Bekins, Barbara, Blake, Ruth E., Cragg, Barry A., Cypionka, Heribert, Dickens, Gerald R., Ferdelman, Timothy G., Ford, Kathryn H., Gettemy, Glen L., Guerin, Gilles, Hinrichs, Kai-Uwe, Holm, Nils G., House, Christopher H., Inagaki, Fumio, Meister, Patrick, Mitterer, Richard M., Naehr, Thomas H., Niitsuma, Sachiko, Parkes, R. John, Schippers, Axel, Skilbeck, C. Gregory, Smith, David C., Spivack, Arthur J., Teske, Andreas P., Wiegel, Juergen, Proceedings of the Ocean Drilling Program; scientific results; controls on microbial communities in deeply buried sediments, eastern Equatorial Pacific and Peru Margin; covering Leg 201 of the cruises of the drilling vessel JOIDES Resolution; San Diego, California, to Valparaiso, Chile; Sites 1225-1231; 27 January-29 March 2002, 201, georefid:2007-008193

Abstract:
This study addresses the problem of diagenetic fractionation of delta (super 15) N in sedimentary organic matter by constructing isotopic mass balances for the sedimentary nitrogen and pore water ammonium at two Ocean Drilling Program (ODP) sites, 1227 and 1230. At Site 1230, ammonium production flux integrated through the sedimentary column indicates that >60% of organic matter is lost to decomposition. The delta (super 15) N of pore water ammonium is <0.7% different from that of the sedimentary organic matter, which implies that very little isotopic fractionation is associated with degradation of organic matter at this site. The constant delta (super 15) N of the solid-phase sedimentary nitrogen through the whole profile supports this conclusion. Atomic C/N ratios (9-12) indicate that organic matter at this site is primarily of marine origin. At Site 1227, the sedimentary organic matter appears to be a mixture of terrestrial and marine components. Ammonium is approximately 4% heavier than the organic matter. The observed isotopic enrichment of pore water ammonium relative to the sedimentary nitrogen might indicate either the preferential decomposition of isotopically heavier marine fraction of the organic matter, or possibly, a nonsteady-state condition of the ammonium concentration and delta (super 15) N profiles. Interpretation of the results at Site 1227 is further complicated by the contribution of ammonium with delta (super 15) N of approximately 4% that is diffusing upward from Miocene brines.
Coverage:
West: -80.3500 East: -79.5700 North: -9.0000 South: -9.0700
Relations:
Expedition: 201
Site: 201-1227
Site: 201-1230
Supplemental Information:
Available only on CD-ROM in PDF format and on the Web in PDF or HTML
Data access:
Provider: SEDIS Publication Catalogue
Data set link: http://sedis.iodp.org/pub-catalogue/index.php?id=10.2973/odp.proc.sr.201.117.2006 (c.f. for more detailed metadata)
Data download: application/pdf
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