Preservation of organic matter and alteration of its carbon and nitrogen isotope composition during simulated and in situ early sedimentary diagenesis

Lehmann, Moritz F.; Bernasconi, Stefano M.; Barbieri, Alberto; McKenzie, Judith A.

doi:10.1016/s0016-7037(02)00968-7

Cited by 725 publications

(476 citation statements)

References 59 publications

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“…Diagenetic alteration under oxic conditions usually increases the ␦ 15 N composition of organic matter (Gaye et al, 2009;Lehmann et al, 2002;Möbius et al, 2011;Nakanishi and Minagawa, 2003). This is Jiang et al, 2012;Steiner et al, 2007;Zhu et al, 2007) and stratigraphic columns of Sancha and Yuanjia sections (after Li et al, 2012b andGuo et al, 2013). because amino acids are much more easily degraded and therefore release more 14 N under oxic than anoxic conditions (Nguyen and Harvey, 1997).…”

Section: The Marine Nitrogen Cyclementioning

confidence: 99%

Marine redox variations and nitrogen cycle of the early Cambrian southern margin of the Yangtze Platform, South China: Evidence from nitrogen and organic carbon isotopes

Wang

Struck

Guo

et al. 2015

Precambrian Research

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Section: The Marine Nitrogen Cyclementioning

confidence: 99%

Marine redox variations and nitrogen cycle of the early Cambrian southern margin of the Yangtze Platform, South China: Evidence from nitrogen and organic carbon isotopes

Wang

Struck

Guo

et al. 2015

Precambrian Research

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“…Alternative nitrogenases containing V or Fe instead of Mo are less efficient and impart fractionations of -6‰ to -8‰ (Zhang et al, 2014); there is so far no evidence of biological N 2 fixation by alternative nitrogenases in the Precambrian δ 15 N record (Section 4). Diagenetic remineralization of organic-bound ammonium to dissolved NH 4 + renders residual biomass isotopically heavier by 1.4-2.3‰ under oxic conditions (Freudenthal et al, 2001;Lehman et al, 2002;Moebius, 2013), but under anoxic conditions the effect is probably much smaller and maybe even reversed if light nitrogen is added by anaerobic diazotrophs (Lehman et al, 2002;Robinson et al, 2012) (Section 3.2). In an anoxic environment where fixed nitrogen is scarce and Mo-based nitrogen fixation is the major mode of nitrogen acquisition, one would thus expect δ 15 N values between -2‰ and +1‰ in carbonaceous sediments.…”

Section: A Primer On Nitrogen Isotopes In Geological Samplesmentioning

confidence: 99%

“…Under oxic diagenetic conditions in both natural and laboratory settings, δ 15 N values of bulk sediments can increase by up to ~4‰, especially when sedimentation rates are low and the exposure to oxygen is relatively long (e.g. Altabet et al, 1999;Freudenthal et al, 2001;Lehman et al, 2002). This increase is likely due to isotopic fractionations during NH 4 + release and partial oxidation in pore waters (Moebius, 2013;Prokopenko et al, 2006).…”

Section: Preservation Of Nitrogen Isotopes In the Rock Recordmentioning

confidence: 99%

“…This increase is likely due to isotopic fractionations during NH 4 + release and partial oxidation in pore waters (Moebius, 2013;Prokopenko et al, 2006). In contrast, diagenesis under anoxic conditions, or under oxic conditions with high sedimentation rates, only imparts small isotopic fractionations of <1‰, making bulk sedimentary nitrogen slightly lighter (Altabet et al, 1999;Lehman et al, 2002;Thunell et al, 2004). Anoxic diagenesis therefore has minimal effect on the utility of the δ 15 N proxy in deep time.…”

Section: Preservation Of Nitrogen Isotopes In the Rock Recordmentioning

confidence: 99%

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The evolution of Earth's biogeochemical nitrogen cycle

Stüeken

Kipp

Koehler

et al. 2016

Earth-Science Reviews

290

287

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Nitrogen is an essential nutrient for all life on Earth and it acts as a major control on biological productivity in the modern ocean. Accurate reconstructions of the evolution of life over the course of the last four billion years therefore demand a better understanding of nitrogen bioavailability and speciation through time. The biogeochemical nitrogen cycle has evidently been closely tied to the redox state of the ocean and atmosphere. Multiple lines of evidence indicate that the Earth"s surface has passed in a non-linear fashion from an anoxic state in the Hadean to an oxic state in the later Phanerozoic. It is therefore likely that the nitrogen cycle has changed markedly over time, with potentially severe implications for the productivity and evolution of the biosphere. Here we compile nitrogen isotope data from the literature and review our current understanding of the evolution of the nitrogen cycle, with particular emphasis on the Precambrian. Combined with recent work on redox conditions, trace metal availability, sulfur and iron cycling on the early Earth, we then use the nitrogen isotope record as a platform to test existing and new hypotheses about biogeochemical pathways that may have controlled nitrogen availability through time. Among other things, we conclude that (a) abiotic nitrogen sources were likely insufficient to sustain a large biosphere, thus favoring an early origin of biological N 2 fixation, (b) evidence of nitrate in the Neoarchean and Paleoproterozoic confirm current views of increasing surface oxygen levels at those times, (c) abundant ferrous iron and sulfide in the midPrecambrian ocean may have affected the speciation and size of the fixed nitrogen reservoir, and (d) nitrate availability alone was not a major driver of eukaryotic evolution.

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“…We thus do not separate denitrification from anammox in the context of this paper and just state that both are tied to oxygen deficient waters. A possible bias on the use of 15 N/ 14 N ratios as a proxy for denitrification intensity is the differential degradation of proteinaceous biological products under oxic and anoxic conditions (Gaye-Haake et al 2005;Lehmann et al 2002). Several studies suggested that the d 15 N ratio of material deposited under suboxic to anoxic conditions is lower than that of material deposited under oxic conditions.…”

Section: Nutrient Abundance/denitrification Proxy: Nitrogen Isotopic mentioning

confidence: 99%

Variability in upwelling intensity and nutrient regime in the coastal upwelling system offshore Namibia: results from sediment archives

Emeis

Struck

Leipe

et al. 2007

Int J Earth Sci (Geol Rundsch)

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The coastal upwelling system offshore Namibia is ideally suited to address a focal question of the Integrated Marine Biogeochemistry and Ecosystem Research Programme: what are the mechanisms that drive long-term changes in ecosystems? Considerable interannual variability in climatic forcing is indicated by long time series of meteorological and remote sensing observation; these accompany considerable interannual to interdecadal changes in the upwelling intensity over the last 100 years, as well as a centennial trend. On longer time scales, the only archives available are sediment records spanning the late Holocene. To decipher the sediment record, we mapped surface-sediment patterns of proxies for physical (sea surface temperature/SST from alkenone unsaturation indexes) and nutrient (d 15 N on bulk sedimentary N) variables. Their present-day surface-sediment patterns outline the coastal upwelling cells and filaments and associated high productivity area. Analysed in an array of dated sediment cores, the spatial patterns of SST suggest long-term ([100 years) variability in the location and intensity of individual upwelling cells. The patterns of d 15 N outline an area of intense denitrification near the coast, and advection of water with low-oxygen concentrations in the undercurrent from the North. d 15 N exhibits considerable downcore variability, in particular over the last 50 years. The variability appears to be governed by differences in extent of denitrification and thus of the shelf oxygen balance, which appears to have deteriorated in the last 50 years. Together, the data suggest that SST and denitrification conditions have remained in the narrow bounds outlined by today's patterns in surface sediments, but that spatially small variability in upwelling intensity and make-up of upwelling feed waters induced considerable changes in the lower trophic levels of the coastal upwelling ecosystem over the last 6,000 years. Attempts to correlate proxy records from sediments with observational time series and regional climate reconstructions were not successful, possibly because annual to interannual environmental signals are erased in the process of sediment formation.

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Preservation of organic matter and alteration of its carbon and nitrogen isotope composition during simulated and in situ early sedimentary diagenesis

Cited by 725 publications

References 59 publications

Marine redox variations and nitrogen cycle of the early Cambrian southern margin of the Yangtze Platform, South China: Evidence from nitrogen and organic carbon isotopes

Marine redox variations and nitrogen cycle of the early Cambrian southern margin of the Yangtze Platform, South China: Evidence from nitrogen and organic carbon isotopes

The evolution of Earth's biogeochemical nitrogen cycle

Variability in upwelling intensity and nutrient regime in the coastal upwelling system offshore Namibia: results from sediment archives

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