Carbon and nitrogen ratio and δ13С values in polygonal landscapes on the coast of the Gulf of Oneman, Chukotka

The subject of the study is the analysis of the ratio of carbon (C) and nitrogen(N) and δ13C values in polygonal landscapes on the coast of Onemen Bay, near the Anadyr city. The maximum values of carbon (59.09%) and nitrogen (2.18%) in peatlands were obtained at a depth of 1.1 m in a narrow peat vein. The values of δ13C in the peatlands on the coast of Onemen Bay vary from -24.1% to -28.6%, the N content varies from 0.37% to 3.24%, the C content varies from 3.1% to 59.09%, the C/N value varies from 8.3 to 34.4.The values of δ13C and C/N values in the 1.5-m peat correspond to C3 plants, the values of δ13C and C/N values for a 2.5–m peat suggest the presence of algae along with plants C3. Fluctuations in the nitrogen and organic carbon content in the section of a 1.5-meter peatland to a depth of 0.8 m are synchronous, which suggests an autochthonous mechanism of peat accumulation, below depth of 0.8-1.2 m, there is a lightening of the carbon isotope composition, which suggests the participation of reworked organic matter in the beginning of peat accumulation. Fluctuations in the nitrogen and organic carbon content in the section of a 2.5-meter peat bog are synchronous, which suggests an autochthonous mechanism of peat accumulation.

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Late Quaternary Upwelling Variations in the Eastern Equatorial Atlantic Ocean as Inferred from Dinoflagellate Cysts, Planktonic Foraminifera, and Organic Carbon Content

Quaternary Research ◽

10.1006/qres.2000.2139 ◽

2000 ◽

Vol 54 (1) ◽

pp. 58-67 ◽

Cited By ~ 9

Author(s):

Christine Höll ◽

Sylvia Kemle-von Mücke

Keyword(s):

Organic Carbon ◽

Atlantic Ocean ◽

Carbon Content ◽

Isotope Composition ◽

Late Quaternary ◽

Planktonic Foraminifera ◽

Organic Carbon Content ◽

Equatorial Atlantic ◽

Northern Summer ◽

Equatorial Atlantic Ocean

Analysis of multiple proxies shows that eastern equatorial Atlantic upwelling was subdued during isotope stage 5.5, more intense during stages 4, 5.2, 5.4, and 6, and most intense early in stage 2. These findings are based on proxy measures from a core site about 600 km southwest of Liberia. The proxies include total organic carbon content, the ratio of peridinoid and oceanic organic-walled dinoflagellate cyst species, accumulation rates of calcareous dinoflagellates, estimates of sea surface paleotemperatures, the difference in stable oxygen isotope composition between two species of planktonic foraminifera that live at different water depths, and the abundance of the planktonic foraminifera Neogloboquadrina dutertrei. Most of these parameters consistently vary directly or inversely with one another. Slight discrepancies between the individual parameters show the usefulness of a multiple proxy approach to reconstruct paleoenvironments. Our data confirm that northern summer insolation strongly influences upwelling in the eastern equatorial Atlantic Ocean.

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