Nitrogen Isotopes in the Ocean

Sigman, Daniel M.; Karsh, Kristen; Casciotti, Karen L.

doi:10.1016/b978-012374473-9.00632-9

Cited by 208 publications

(203 citation statements)

References 5 publications

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“…The nitrogen isotopic fractionation associated with cyanobacterial nitrogen fixation is small, ca. − 2 to 0‰ (Sigman and Casciotti, 2001;Brandes and Devol, 2002). However, larger fractionations (up to − 7‰) have been reported for environments that are iron-rich (Zerkle et al, 2008) or in which nitrogen fixation is based on alternative (i.e., vanadiumand iron-bearing) nitrogenases (Zhang et al, 2014).…”

Section: Significance Of the Mid-tournaisian Nitrogen Isotope Eventmentioning

confidence: 94%

“…In the modern ocean, the δ 15 N of seawater nitrate is controlled by the flux and isotopic compositions of nitrogen entering and leaving the ocean (Sigman and Casciotti, 2001;Struck, 2012). The principal input of nitrogen is direct fixation of atmospheric N 2 by diazotrophic cyanobacteria, although smaller amounts of nitrogen are supplied by rain, rivers, and lightning strikes (Zehr et al, 2008).…”

Section: Significance Of the Mid-tournaisian Nitrogen Isotope Eventmentioning

confidence: 98%

“…The nitrogen isotopic compositions of marine sediments can be affected by a number of influences (e.g., Sigman and Casciotti, 2001;Freudenthal et al, 2001;Lehmann et al, 2002;Higgins et al, 2012; see review in Algeo et al, 2014). As all of the study samples consist of carbonate with a low content of clay minerals, the nitrogen present is likely to have been derived mainly from organic matter.…”

Section: Diagenetic Influencesmentioning

confidence: 99%

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The TICE event: Perturbation of carbon–nitrogen cycles during the mid-Tournaisian (Early Carboniferous) greenhouse–icehouse transition

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Section: Significance Of the Mid-tournaisian Nitrogen Isotope Eventmentioning

confidence: 94%

Section: Significance Of the Mid-tournaisian Nitrogen Isotope Eventmentioning

confidence: 98%

Section: Diagenetic Influencesmentioning

confidence: 99%

See 1 more Smart Citation

The TICE event: Perturbation of carbon–nitrogen cycles during the mid-Tournaisian (Early Carboniferous) greenhouse–icehouse transition

et al. 2015

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“…The FB-δ 15 (54). In the case of the Subantarctic, the greatest violation of the Rayleigh model is the summertime lateral nitrate supply from the Antarctic Polar Frontal Zone (20).…”

Section: Nitrate Drawdown During Ice Agesmentioning

confidence: 99%

Iron Fertilization of the Subantarctic Ocean During the Last Ice Age

Martínez‐García

Sigman

Ren

et al. 2014

Science

412

433

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The sediment core TN057-06-PC4 (hereafter TN057-6) was retrieved from the Agulhas Ridge (42º 54.8' S, 8º 54.0' E, 3751 m) during the pre-site survey of the Ocean Drilling Program (ODP) Leg 177 at nearly the same position as ODP Site 1090 (42° 54.5′ S, 8° 54.0′ E, at 3,702 m). The high-resolution XRF Fe concentration records from ODP Site 1090 and TN57-06 were used to align the two cores using the software Analyseries (46). The good correlation of the two records after the alignment allows us to directly compare the measurements performed in the two cores with minimal stratigraphic uncertainty (Fig. S1a). This indicates that the 230 Th measurements performed in can be used to reconstruct sedimentary fluxes of different elements and/or organic compounds in both records.For example, in Figure S1c, the high-resolution 230 Th-normalized mass flux (Fig.S1b) was used to calculate iron fluxes both in ODP Site 1090 and TN057-6 ( The age model of our record was generated by graphic correlation of the highresolution 230 Th-normalized Fe flux from ODP Site 1090 to the most recent ice core dust reconstruction from EPICA Dome C (44), using ice core chronology (AICC2012) (47,48) (Fig. S2). This new age model is generally in good agreement with the original ages proposed by Venz and Hodell 2002 (65) using benthic δ 18 O stratigraphy (Fig. S3). The good correlation of ODP Site 1090 Fe flux and EDC dust records down to sub-millennial timescales allows us to directly compare our marine data to other ice core measurements (e.g., atmsopheric pCO 2 ) with minimal stratigraphic uncertainty (Fig. S2). Foraminifera-bound δ 15 N analysisAround 600-800 specimens of G. bulloides and O. universa were picked manually under a dissecting microscope (250-425--6 mg of clean foraminiferal calcite. Foraminifera-bound δ 15 N was measured at Princeton University following the protocol described in (23,32). In the intervals where foraminifera abundances were adequate, samples were measured in duplicate. The reported error 2 bars in Fig. S9 represent the standard deviation estimated from the means of duplicated measurements. The average standard deviation of all the replicated measurements (from foraminifera-bound organic matter oxidation onward) was 0.19‰. Bulk sediment δ 15 N and %Nitrogen analysisThe N content and δ 15 N of the bulk sediment were analyzed using a Thermo FisherSeries 1112 elemental analyzer coupled with a Thermo Fisher Delta V Plus mass spectrometer at ETH Zurich. Between 50 and 100 mg of sediment were used for eachanalysis. An in-house peptone standard, which has been referenced to international reference materials (IAEA-N1 and IAEA-N2), was measured in each sample run and used for the final corrections. The standard deviation for the peptone standard among the different runs was <0.1‰. 230 Th and opal analysisConcentrations of U and Th isotopes were measured by inductively coupled-plasma mass spectrometry after strong acid sediment digestion and chromatographic separation as described by Fleisher and Anderson, 2003 (49). Opal...

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“…Here, the fractionation of d 15 N in rotifers appeared to concord with changes in nitrogen derived from FPOM and phytoplankton, which may suggest that nitrogen is derived from phytoplankton and old recycled organic materials in the waterbody. Nitrate inflow into the aquatic ecosystem from anthropogenic sources is known to induce a progressive 15 N enrichment of the nitrogen pool (Sigman & Casciotti, 2001). The present result therefore suggest that rotifers obtain their carbon and nitrogen sources through different sources in the lake.…”

Section: Discussionmentioning

confidence: 86%

Elemental ratios (C:N) and stable isotopic composition of dominant rotifer species in a tropical eutrophic alkaline–saline Lake Nakuru (Kenya)

et al. 2014

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Rotifers dominate zooplankton biomass of many aquatic environments. However, their link to food web biomass has rarely been elucidated in alkaline-saline lakes. Variations in C content, C:N ratio and stable isotope composition (d 13 C, d 15 N) of dominant rotifer species were studied from January to December 2008 in alkaline-saline Lake Nakuru to provide insights into their bioenergetics. We established that Brachionus dimidiatus dominated in terms of abundance (80,000-100,000 9 10 3 ind m -3 ) and C-biomass. Also B. dimidiatus constituted about 60-75% of the rotifer biomass in the samples. All the rotifer species exhibited significant (P \ 0.05) seasonal differences in biomass, C and C:N ratios. Rotifers had lower mean d 13 C than course particulate organic matter, fine particulate organic matter and fish, but higher than mean d 13 C in the dominant phytoplankton species. In all species, d 13 C and d 15 N increased markedly during the rainy season reflecting the feeding onset on allochthonous food sources. The isotopic increase correlated with an increase in their C:N. Our results demonstrate that rotifers respond quickly to any increase in primary production and can cope with changes in its nature and timing.

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Nitrogen Isotopes in the Ocean

Cited by 208 publications

References 5 publications

The TICE event: Perturbation of carbon–nitrogen cycles during the mid-Tournaisian (Early Carboniferous) greenhouse–icehouse transition

The TICE event: Perturbation of carbon–nitrogen cycles during the mid-Tournaisian (Early Carboniferous) greenhouse–icehouse transition

Iron Fertilization of the Subantarctic Ocean During the Last Ice Age

Elemental ratios (C:N) and stable isotopic composition of dominant rotifer species in a tropical eutrophic alkaline–saline Lake Nakuru (Kenya)

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