15N/14N variations in Cretaceous Atlantic sedimentary sequences: implication for past changes in marine nitrogen biogeochemistry

Rau, Greg H.; Arthur, Michael A.; Dean, Walter E.

doi:10.1016/0012-821x(87)90201-9

Cited by 170 publications

(91 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Coupling with abundant geohopanoids, derivatives of components of cellular membrane of prokaryotes, in these samples, they concluded the diazotrophic cyanobacteria could have been major primary producers during the OAE2. The δ bulk values in the Cretaceous black shales were also reported by Rau et al (1987). They determined the δ bulk of the black shales (they referred them "laminated black marlstone" and "black clay stone") from DSDP sites 367, 530, and 603 in Atlantic Ocean and found that the δ bulk values are in a range from -2.7 to +0.6‰, whereas those of adjacent organic-poor rock samples were substantially higher than those (-0.7 to +5.7‰).…”

Section: Nitrogen Isotopic Composition Of Bulk Sediments Insupporting

confidence: 64%

The importance of diazotrophic cyanobacteria as primary producers during Cretaceous Oceanic Anoxic Event 2

et al. 2006

View full text Add to dashboard Cite

Abstract. In Livello Bonarelli black shale deposited during Cretaceous Oceanic Anoxic Event 2 (OAE-2, ca. 94 Ma), nitrogen isotopic compositions of bulk sediments are mostly in a narrow range from -2.7 to -0.7‰. We also determined molecular distribution and nitrogen isotopic compositions of geoporphyrins extracted from the black shale. The nitrogen isotopic compositions of C 32 Ni deoxophylloerythroetioporphyrin (DPEP) and total Ni porphyrins are -3.5 and -3.3‰, respectively, leading us to the estimation that the mean nitrogen isotopic composition of photoautotrophic cells were around +1‰ during the formation of Bonarelli black shale. This value is suggestive of N 2 -fixation, a dominant process for these photoautotrophs when assimilating nitrogen. Furthermore, Ni-chelated C 32 DPEP, derived mainly from chlorophyll a had the highest concentration. Based on this evidence, we conclude that diazotrophic cyanobacteria were major primary producers during that time. Cyanobacteria may be key photoautotrophs during the formation of black shale type sediments intermittently observed throughout the later half of the Earth's history, and hence may have played a crucial role in the evolution of geochemical cycles even in the later half of the Earth's history.

show abstract

Section: Nitrogen Isotopic Composition Of Bulk Sediments Insupporting

confidence: 64%

The importance of diazotrophic cyanobacteria as primary producers during Cretaceous Oceanic Anoxic Event 2

et al. 2006

View full text Add to dashboard Cite

show abstract

“…This hypothesis is supported by the canonical view that the final step in the oxygenation of Earth"s surface occurred in the Neoproterozoic (Section 2.1) and that therefore the Phanerozoic ocean was fully oxygenated with only brief interruptions during anoxic events that favored a temporary return to anaerobic nitrogen cycling (e.g. Junium and Arthur, 2007;Ohkouchi et al, 2006;Rau et al, 1987;Schoepfer et al, 2012;Sephton et al, 2002). However, it is possible that the redox state of the ocean was not stable in the early Phanerozoic, and this may have significantly affected nitrogen cycling.…”

Section: Phanerozoic (Since ~05 Gyr)mentioning

confidence: 88%

The evolution of Earth's biogeochemical nitrogen cycle

Stüeken

Kipp

Koehler

et al. 2016

Earth-Science Reviews

329

287

View full text Add to dashboard Cite

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.

show abstract

“… 15 N org values of type II kerogens (Fig. 4a) are typical for black shales where  15 N is usually between -3 and +2‰ (e.g., Rau et al, 1987;Dumitrescu and Brassell, 2006;Meyers, 2006 Boudou et al, 1984a;Burchill and Welch, 1989;Whiticar, 1996;Ader et al, 1998a;Rimmer et al, 2006). …”

Section: Elemental Rank and Isotopic Characterizationmentioning

confidence: 98%

Organic nitrogen chemistry during low-grade metamorphism

Boudou

Schimmelmann

Ader

et al. 2008

Geochimica et Cosmochimica Acta

136

View full text Add to dashboard Cite

-Most of the organic nitrogen (N org ) on Earth is disseminated in crustal sediments and rocks in the form of fossil nitrogen-containing organic matter. The chemical speciation of fossil N org within the overall molecular structure of organic matter changes with time and heating during burial. Progressive thermal evolution of organic matter involves phases of enhanced elimination of N org and ultimately produces graphite containing only traces of nitrogen. Long-term chemical and thermal instability makes the chemical speciation of N org a valuable tracer to constrain the history of sub-surface metamorphism and to shed light on the subsurface biogeochemical nitrogen cycle and its participating organic and inorganic nitrogen pools. This study documents the evolutionary path of N org speciation, transformation and elimination before and during metamorphism and advocates the use of XRay Photoelectron Spectroscopy (XPS) to monitor changes in N org speciation as a diagnostic tool for organic metamorphism. Our multidisciplinary evidence from XPS, stable isotopes, traditional quantitative coal analyses, and other analytical approaches shows that at the metamorphic onset N org is dominantly present as pyrrolic and pyridinic nitrogen. The relative abundance of nitrogen substituting for carbon in condensed, partially aromatic systems (where N is covalently bonded to three C atoms) increases exponentially with increasing metamorphic grade, at the expense of pyridinic and pyrrolic nitrogen. At the same time, much N org is eliminated without significant nitrogen isotope fractionation. The apparent absence of Rayleigh-type nitrogen isotopic fractionation suggests that direct thermal loss of nitrogen from an organic matrix does not serve as a major pathway for N org elimination. Instead, we propose that hot H, O-containing fluids or some of their components gradually penetrate into the carbonaceous matrix and eliminate N org along a progressing reaction front, without causing nitrogen isotope fractionation in the residual N org in the unreacted core of the carbonaceous matrix. Before the reaction front can reach the core, an increasing part of core N org chemically stabilizes in the form of nitrogen atoms substituting for carbon in condensed, partially aromatic systems forming graphite-like structural domains with delocalized π-electron systems (nitrogen atoms substituting for "graphitic" carbon in natural metamorphic organic matter). Thus, this nitrogen species with a conservative isotopic composition is the dominant form of residual nitrogen at higher metamorphic grade.

show abstract

15N/14N variations in Cretaceous Atlantic sedimentary sequences: implication for past changes in marine nitrogen biogeochemistry

Cited by 170 publications

References 35 publications

The importance of diazotrophic cyanobacteria as primary producers during Cretaceous Oceanic Anoxic Event 2

The importance of diazotrophic cyanobacteria as primary producers during Cretaceous Oceanic Anoxic Event 2

The evolution of Earth's biogeochemical nitrogen cycle

Organic nitrogen chemistry during low-grade metamorphism

Contact Info

Product

Resources

About