Carbon isotope ratios of organic matter in Bering Sea settling particles: Extremely high remineralization of organic carbon derived from diatoms

2016 ◽  
Vol 50 (3) ◽  
pp. 241-248 ◽  
Author(s):  
Saki Yasuda ◽  
Tasuku Akagi ◽  
Hiroshi Naraoka ◽  
Fumio Kitajima ◽  
Kozo Takahashi
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Carbon Isotope ◽  
Bering Sea ◽  
Isotope Ratios ◽  
Carbon Isotope Ratios ◽  
Settling Particles

Carbon Isotope Ratios of Particulate Organic Matter in the Gulf of St. Lawrence

1979 ◽  
Vol 36 (6) ◽  
pp. 678-682 ◽  
Author(s):  
F. C. Tan ◽  
P. M. Strain
Keyword(s):  
Organic Matter ◽  
Surface Water ◽  
Organic Carbon ◽  
Carbon Isotope ◽  
Particulate Organic Matter ◽  
Surface Sediments ◽  
Isotope Ratios ◽  
Lawrence Estuary ◽  
Carbon Isotope Ratios ◽  
Surface Samples

Sixteen offshore surface samples within the Gulf of St. Lawrence show low δ13C values and are similar to eight offshore surface samples collected seaward of the Gulf of St. Lawrence. The δ13C surface values are consistent with δ13C values in plankton produced at the temperature found in the euphotic zone in the study area. Higher values are observed in four surface samples from the mouth of the St. Lawrence Estuary and probably result from high carbon demand during periods of high biological productivity. Lower values found in seven deep POC samples indicate changes in the nature of the POC caused by biological degradation of the organic matter. Significant differences (2–6‰) between the uniformly high δ13C values of the organic carbon in surface sediments and the low values of near-bottom water POC have been observed. The similarity between the δ13C values of surface water POC and the surface sediments suggest that surface water POC is an important source of organic carbon in surface sediments. Several observations of large vertical δ13C gradients in deep water POC suggest the presence of resuspended sediments 30–60 m above the sediment–water interface. Key words: particulate organic matter, carbon isotope ratios, isotope fractionation, sediment resuspension, sediment sources, Gulf of St. Lawrence

Organic carbon isotope ratios and paleoenvironmental implications for Holocene sediments in Lake Melville, southeastern Labrador

1987 ◽  
Vol 24 (10) ◽  
pp. 1994-2003 ◽  
Author(s):  
F. C. Tan ◽  
G. Vilks
Keyword(s):  
Organic Carbon ◽  
Carbon Isotope ◽  
Sediment Cores ◽  
Isotope Ratios ◽  
Carbon Isotope Ratios ◽  
Organic Carbon Isotope ◽  
Glacial Runoff ◽  
Bottom Waters ◽  
History Of ◽  
Marine Influence

Stable isotope 13C/12C ratios of organic carbon in sediments and in particulate organic carbon (POC) change from typically marine values in Groswater Bay to those of terrestrial soils in Goose Bay along an offshore–onshore transect in Hamilton Inlet, southeastern Labrator. The δ13C values in POC collected from close to the water surface change relatively little in Lake Melville, indicating that the integrity of the runoff plume is maintained as it spreads in Lake Melville. The organic carbon isotope ratios in POC collected from the near-bottom waters are similar to those of surficial sediments.Downcore δ13C values reflect paleo-oceanographic changes in Hamilton Inlet during and since deglaciation. In two sediment cores that reached sufficiently old sediments (10 000 years BP), the δ13C values change toward the bottom of the cores to values similar to those of the terrestrial organic carbon in soils, signifying greater terrestrial influence during deglaciation and during the early Holocene.According to the history of postglacial isostatic readjustment of the area, Lake Melville basin was more open to the marine waters during the early postglacial marine incursion because of deeper channels leading into Lake Melville. As a consequence, evidence for greater marine influence during that time should be found in sediment cores. The lack of evidence for the deposition of marine organic carbon brought in by the marine counterflow waters suggests a proximal glaciomarine environment in the Lake Melville basin. Glacial runoff diluted the basin waters, and it is possible that the whole inner Labrador Shelf was relatively fresh during that time.

In situ iron isotope analyses of pyrite and organic carbon isotope ratios in the Fortescue Group: Metabolic variations of a Late Archean ecosystem

2012 ◽  
Vol 212-213 ◽  
pp. 169-193 ◽  
Author(s):  
Kazumi Yoshiya ◽  
Manabu Nishizawa ◽  
Yusuke Sawaki ◽  
Yuichiro Ueno ◽  
Tsuyoshi Komiya ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Carbon Isotope ◽  
Isotope Ratios ◽  
Iron Isotope ◽  
Carbon Isotope Ratios ◽  
Organic Carbon Isotope ◽  
Isotope Analyses
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