Isotopic variations of the nitrogen in Lake Superior

Pang, P. C.; Nriagu, Jerome O.

doi:10.1016/0016-7037(77)90051-5

Cited by 43 publications

(17 citation statements)

References 10 publications

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“…The values of ε 15 and ε 18 computed by us are −8.7 and −10.7 ‰, respectively. The ε 15 is much lower than those obtained from laboratory cultures (Olleros, 1983; Table 1) as well as open-ocean OMZs (oxygen minimum zones) (Brandes et al, 1998;Voss et al, 2001; Table 1), although it is close to the ε 15 reported from the eutrophic Lake Lugano. Factors controlling denitrification rates in aquatic systems include temperature, availability of nitrate and organic carbon, oxygen concentration and type of bacterium involved (Seitzinger, 1988;Böttcher et al, 1990, and references therein).…”

Section: Denitrificationmentioning

confidence: 71%

“…These transformations involve isotopic fractionation to varying degrees, and therefore natural abundance of stable isotopes ( 15 N and 14 N) in various N species provides useful insight into nitrogen cycling besides its sources/sinks in the oceanic (Altabet, 1988;Sigman et al, 2005), coastal (Thunell et al, 2004;Hu et al, 2016) and estuarine (Cifuentes et al, 1988;Savoye et al, 2012) water bodies and sediments. Studies have also been undertaken in freshwater systems such as lakes (Pang and Nriagu, 1977;Chen et al, 2014) and reservoirs Junet et al, 2009). Some of the best studied freshwater ecosystems in this regard are Lake Lugano at the Swiss-Italian border, Lake Kinneret in Israel and Lake Superior in the USA.…”

Section: Introductionmentioning

confidence: 99%

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Isotopic composition of nitrate and particulate organic matter in a pristine dam reservoir of western India: implications for biogeochemical processes

et al. 2017

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Abstract. Isotopic composition of nitrate (δ 15 N and δ 18 O) and particulate organic matter (POM; δ 15 N and δ 13 C) were measured in the Tillari Reservoir, located at the foothills of the Western Ghats, Maharashtra, western India. The reservoir, which is stratified during spring-summer and autumn seasons but gets vertically mixed during the southwest monsoon (SWM) and winter, is characterized by diverse redox nitrogen transformations in space and time. The δ 15 N and δ 18 O values of nitrate were low (δ 15 N = 2-10 ‰, δ 18 O = 5-8 ‰) during normoxic conditions but increased gradually (the highest at δ 15 N = 27 ‰, δ 18 O = 29 ‰) when anoxic conditions facilitated denitrification in the hypolimnion during spring-early summer. Once nitrate was fully utilized and sulfidic conditions set in, NH + 4 became the dominant inorganic N species, with δ 15 N ranging from 1.3 to 2.6 ‰. Low δ 15 N (∼ −5 ‰) and δ 13 C (−37 to −32 ‰) of POM cooccurring with high NH + 4 and CH 4 in sulfidic bottom waters were probably the consequence of microbial chemosynthesis. Assimilation of nitrate in the epilimnion was the major controlling process on the N isotopic composition of POM (δ 15 N = 2-6 ‰). Episodic low δ 15 N values of POM (−2 to 0 ‰) during early summer, coinciding with the absence of nitrate, might arise from N fixation, although further work is required to confirm the hypothesis. δ 13 C POM in the photic zone ranged between −29 and −27 ‰ for most parts of the year. The periods of mixing were characterized by uniform δ 15 N-NO

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Section: Denitrificationmentioning

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Isotopic composition of nitrate and particulate organic matter in a pristine dam reservoir of western India: implications for biogeochemical processes

et al. 2017

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“…4). If the source of the sediment nitrogen was autochthonous the expected 615N values would be the same as the biota (Peters et al 1978) or heavier (Pang & Nriagu 1977). If the sediment material had a significant amount of terrestrial material then a lighter signal would be expected (Peterson & Fry 1987).…”

Section: Discussionmentioning

confidence: 93%

The organic carbon budget of a shallow arctic tundra lake on the Tuktoyaktuk Peninsula, N.W.T., Canada

et al. 1994

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Abstract. The organic carbon cycle of a shallow, tundra lake (mean depth 1.45 m) was followed for 5 weeks of the open water period by examining CO, fluxes through benthic respiration and anaerobic decomposition, photosynthesis of benthic and phytoplankton communities and gas exchange at the air-water interface. Total photosynthesis (as consumption of carbon dioxide) was 37.5 mmole C me2 d-r, 83% of which was benthic and macrophytic. By direct measurement benthic respiration exceeded benthic photosynthesis by 6.6 mmole C m-* d-'. The lake lost 1.4 x lo6 moles C in two weeks after ice melted by degassing CO,, and 6.8 mmole C mm2 d-' (1.5 x lo6 moles) during the remainder of the open water period; 2.2 mmole C m-* d-' of this was release of CO, stored in the sediments by cryoconcentration the previous winter. Anaerobic microbial decomposition was only 4% of the benthic aerobic respiration rate of 38 mmole C m-* d-r. An annual budget estimate for the lake indicated that 50% of the carbon was produced by the bentbic community, 20% by phytoplankton, and 30% was allochthonous material. The relative contribution of allochthonous input was in accordance with measurement of the 6"N of sedimented organic matter.

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“…When nitrate concentrations are low, plankton assimil ate ammoni a and dissolved organic nitrogen (DON) (Keeney, 1973) The second possi bl e cause of the 15N enri chment has been observed by several investigators in other situations (Miyake and Wada, 1967;Wada and Hattori, 1976;and Pang and Nriagu, 1977;DeNiro and Epstein, 1981).…”

Section: Discussion Of Plankton Resultsmentioning

confidence: 99%

“…The assumption of minimal isotopic alteration during diagenesis has been made implicitly and explicitly by numerous investigators because of the absence of gradients in sedimentary organic matter ô15N profiles (Pang and Nriagu, 1976;Pang and Nriagu, 1977;Stuermer et al, 1978;Sweeney and Kaplan, 1980). The similarity of the few measurements of the ô1~ of pore-water NH"4 to that of total organi c matter of the sediments has al so suggested that di ageneti c isotopic alteration was unimportant (Sweeney and Kaplan, 1980). Prior to this thesis research, the only evidence for isotopic alteration of PON during transit through the water column was that reported by Sai no and Hattori (1980) for the northeastern Indi an Ocean (See Fi gure 1-6).…”

mentioning

confidence: 99%

Stable isotope geochemistry of nitrogen in marine particulates

Libes¹

1983

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Isotopic variations of the nitrogen in Lake Superior

Cited by 43 publications

References 10 publications

Isotopic composition of nitrate and particulate organic matter in a pristine dam reservoir of western India: implications for biogeochemical processes

Isotopic composition of nitrate and particulate organic matter in a pristine dam reservoir of western India: implications for biogeochemical processes

The organic carbon budget of a shallow arctic tundra lake on the Tuktoyaktuk Peninsula, N.W.T., Canada

Stable isotope geochemistry of nitrogen in marine particulates

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