scholarly journals Data report: clues about carbon cycling in methane-bearing sediments using stable isotopes of the dissolved inorganic carbon, IODP Expedition 311

2009 ◽  
Author(s):  
M.E. Torres ◽  
M. Kastner
Keyword(s):  
Stable Isotopes ◽  
Carbon Cycling ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon

Diel behavior of stable isotopes of dissolved oxygen and dissolved inorganic carbon in rivers over a range of trophic conditions, and in a mesocosm experiment

2010 ◽  
Vol 269 (1-2) ◽  
pp. 22-32 ◽  
Author(s):  
Stephen R. Parker ◽  
Christopher H. Gammons ◽  
Simon R. Poulson ◽  
Michael D. DeGrandpre ◽  
Charmaine L. Weyer ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Dissolved Oxygen ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Mesocosm Experiment ◽  
Trophic Conditions

scholarly journals PHYSICOCHEMICAL AND ISOTOPIC CHARACTERIZATION OF FORMATION WATERS FROM OIL FIELDS IN THE SERGIPE BASIN, BRAZIL

2014 ◽  
Vol 32 (3) ◽  
pp. 531
Author(s):  
Danilo R. Sá Teles ◽  
Antônio Expedito G. de Azevedo ◽  
Alexandre B. Costa ◽  
Maria R. Zucchi ◽  
Alexandre A. Ferreira
Keyword(s):  
Stable Isotopes ◽  
Isotopic Exchange ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Oil Fields ◽  
Northeastern Brazil ◽  
Formation Water ◽  
Water Formation ◽  
Isotopic Characterization

ABSTRACT. This paper presents a study of the physicochemical and isotopic characteristics of formation waters from the Castanhal, Siririzinho and Aguilhadafields in the Sergipe Basin, northeastern Brazil. In each of the samples, pH, conductivity, concentration of dissolved inorganic carbon (DIC), δ18O, δ2H, and δ13C weremeasured. These measurements are used to identify isotopic similarities among waters from local aquifers, which can be used as a proxy for groundwater connectivitywith formation water. Formation waters from the Castanhal and Siririzinho fields are enriched in deuterium, as evidenced by their δ2H values above the Global MeteoricWater Line (GMWL), which may be a result of significant isotopic exchange between water and H2S. These measurements are in accordance with the large enrichment in13C of DIC resulting from biodegradation, with the formation of methane depleted in 13C and CO2 enriched in 13C. These results indicate interaction between formationwater with rocks and other fluids.Keywords: stable isotopes, dissolved inorganic carbon, biodegradation. RESUMO. Este trabalho apresenta um estudo das características físico-químicas e isotópicas de águas de formação dos campos Castanhal, Siririzinho e Aguilhada, localizados na Bacia de Sergipe, nordeste do Brasil. Em cada uma das amostras foram medidos os parâmetros pH, condutividade elétrica, concentração de carbonoinorgânico dissolvido (CID), δ18O, δ2H e δ13C. A partir dos resultados obtidos, foi possível identificar a similaridade isotópica com as águas de aquíferos locais,indicando conexão de água subterrânea com água de formação. As águas de formação dos campos Castanhal e Siririzinho apresentaram um enriquecimento em deutério,resultado da troca isotópica entre a água e o H2S. Também foi verificado, um grande enriquecimento no δ13C do CID, resultado dos processos de biodegradação coma formação de metano empobrecido em 13C e CO2 enriquecido neste isótopo. Os resultados encontrados indicam interação entre a água de formação com as rochas ecom outros fluidos.Palavras-chave: isótopos estáveis, carbono inorgânico dissolvido, biodegradação.

The interplay of glacial/interglacial climate-CO2 and productivity effects on coccolith calcification and vital effects across the MIS 12 to MIS 9 in the western tropical Atlantic

2020 ◽  
Author(s):  
Alba González-Lanchas ◽  
Heather M. Stoll ◽  
José-Abel Flores ◽  
Francisco J. Sierro ◽  
Ivan Hernandez-Almeida ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Isotopic Fractionation ◽  
Tropical Atlantic ◽  
Physiological Mechanisms ◽  
Carbon Isotopic ◽  
Acquisition Strategies ◽  
Climatic Period ◽  
Vital Effects

<p>Coccolithophores play an important dual role in ocean biogeochemistry: they use dissolved inorganic carbon (DIC) in the surface for both photosynthesis and coccolith calcification. Stable isotopes in coccoliths are the result of various effects, including different vital effects, allowing hypotheses about the varying active carbon acquisition strategies in response to changing environmental conditions. Understanding the physiological mechanisms that cause these changes remains challenging.</p><p>The MIS 12 to MIS 9 interval is a crucial climatic period encompassing changing glacial-interglacial cyclicity and pronounced variations in atmospheric CO<sub>2</sub> concentration. Different paleorecords indicate that coccoliths were an important component of the carbonate fraction during this interval, with the outstanding worldwide dominance of the highly calcified coccolithophore species <em>Gephyrocapsa caribbeanica</em>.</p><p>The carbon isotopic fractionation during photosynthesis (εp) in alkenones, biomarkers produced by coccolithophores, is a proxy to reconstruct past aqueous CO<sub>2</sub> concentration. Here we present a new εp reconstruction spanning this glacial/interglacial interval (460 to 330 kyr) at ODP Site 925 in the western tropical Atlantic. We aim to evaluate the interplay of CO<sub>2 </sub>and productivity effects on coccolith calcification and stable isotopes (δ<sup>18</sup>O and δ<sup>13</sup>C) in coccolith calcite integrating these data with the size and thickness of coccolith platelets and the geochemical Sr/Ca record.</p><p>The comparison of mean coccolith size with coeval samples from the deeper ODP Site 929 allows the evaluation of the degree of nannofossil dissolution across the interval.</p>

scholarly journals Inorganic carbon cycling and biogeochemical processes in an Arctic inland sea (Hudson Bay)

2016 ◽  
Vol 13 (16) ◽  
pp. 4659-4671 ◽  
Author(s):  
William J. Burt ◽  
Helmuth Thomas ◽  
Lisa A. Miller ◽  
Mats A. Granskog ◽  
Tim N. Papakyriakou ◽  
...  
Keyword(s):  
Carbon Cycling ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Total Alkalinity ◽  
Hudson Bay ◽  
Near Surface ◽  
Annual Cycles ◽  
Detailed Assessment ◽  
Freshwater Inputs ◽  
End Members

Abstract. The distributions of carbonate system parameters in Hudson Bay, which not only receives nearly one-third of Canada's river discharge but is also subject to annual cycles of sea-ice formation and melt, indicate that the timing and magnitude of freshwater inputs play an important role in carbon biogeochemistry and acidification in this unique Arctic ecosystem. This study uses basin-wide measurements of dissolved inorganic carbon (DIC) and total alkalinity (TA), as well as stable isotope tracers (δ18O and δ13CDIC), to provide a detailed assessment of carbon cycling processes within the bay. Surface distributions of carbonate parameters reveal the particular importance of freshwater inputs in the southern portion of the bay. Based on TA, we surmise that the deep waters in the Hudson Bay are largely of Pacific origin. Riverine TA end-members vary significantly both regionally and with small changes in near-surface depths, highlighting the importance of careful surface water sampling in highly stratified waters. In an along-shore transect, large increases in subsurface DIC are accompanied by equivalent decreases in δ13CDIC with no discernable change in TA, indicating a respiratory DIC production on the order of 100 µmol kg−1 DIC during deep water circulation around the bay.

A high-elevation MIS 5 hydrologic record using mollusks and ostracodes from Snowmass Village, Colorado, USA

2014 ◽  
Vol 82 (3) ◽  
pp. 604-617 ◽  
Author(s):  
Saxon E. Sharpe ◽  
Jordon Bright
Keyword(s):  
Stable Isotopes ◽  
Water Temperature ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
High Elevation ◽  
Total Dissolved Solids ◽  
Water Based ◽  
Fossil Site ◽  
Mis 5E ◽  
Mis 5

AbstractSediments containing terrestrial and aquatic mollusks and ostracodes from the Ziegler Reservoir fossil site (2705 m elevation) near Snowmass Village, Colorado, span ~130–87 ka (MIS 5e through 5b). The southeastern area of the site where taxa were recovered was a relatively fresh, shallow, well-vegetated wetland during MIS 5e through 5c time, approximately 2 m deep, with a total dissolved solids value of ~200–1000 mg L− 1. The wetland was seasonally or annually variable and groundwater discharged along the margins of the bounding moraine. Groundwater likely contributed solutes to the system and may have contributed 18O-enriched water. Based on stable isotopes from ostracode calcite (δ18OOST and δ13COST), seasonal evaporation occurred and the dissolved inorganic carbon pool was unexpectedly enriched in 13C. The mollusk and ostracode faunas changed little across the MIS 5e/5d/5c boundaries, whereas a distinct change in the ostracode fauna occurred between the deposition of Unit 11 and Unit 13, which corresponds in time to the MIS 5c/5b boundary, indicating some combination of increased surface and/or groundwater flow, a decrease in water temperature, and a freshening and a possible deepening of the wetland.

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