14C Measurements of Dissolved Inorganic and Organic Carbon in Qinghai Lake and Inflowing Rivers (NE Tibet, Qinghai Plateau), China

Radiocarbon ◽  
2014 ◽  
Vol 56 (3) ◽  
pp. 1115-1127 ◽  
Author(s):  
A J T Jull ◽  
G S Burr ◽  
W Zhou ◽  
P Cheng ◽  
S H Song ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Qinghai Lake ◽  
Main Process ◽  
The Past ◽  
Atmospheric Exchange ◽  
Sediment Carbon ◽  
Inorganic And Organic

There have been a number of studies that have attempted to estimate the past radiocarbon reservoir effects in Qinghai Lake, China. This article reports on measurements on modern samples collected at the lake in October 2003 and October 2009, which allow us to better understand the systematics of the lake and shed new insights on the processes occurring in the lake. The results indicate that atmospheric exchange of 14C is the main process affecting surface dissolved inorganic carbon (DIC) in the lake, but dissolved organic carbon (DOC) can be explained as a combination of sources. We also conclude that sediment carbon can be explained by a model where input from the surrounding rivers and groundwater are important, in agreement with the model of Yu et al. (2007).

A Syringe Gas-Stripping Procedure for Gas-Chromatographic Determination of Dissolved Inorganic and Organic Carbon in Fresh Water and Carbonates in Sediments

1973 ◽  
Vol 30 (10) ◽  
pp. 1441-1445 ◽  
Author(s):  
Michael P. Stainton
Keyword(s):  
Organic Carbon ◽  
Gas Phase ◽  
Atmospheric Pressure ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Chromatographic Determination ◽  
Canadian Shield ◽  
Gas Stripping ◽  
Inorganic And Organic

A simple, rapid method for determining dissolved inorganic carbon in water is described. A 20-cm3 sample of water is drawn into a 50-cm3 polypropylene syringe and acidified by injection of 1 cm3 of dilute sulphuric acid. Twenty-nine cubic centimeters of helium at atmospheric pressure is injected into the syringe followed by 10 sec of manual agitation to partition CO2 between gas and liquid phase. The gas phase containing 60% of CO2 from the sample is then analyzed by gas chromatography. This method has been used to determine dissolved inorganic and organic carbon in Canadian Shield waters and to determine total carbonates in sediments.

scholarly journals Degradation of permafrost carbon in the Kolyma River

2020 ◽  
Author(s):  
Kirsi Keskitalo ◽  
Lisa Bröder ◽  
Dirk Jong ◽  
Nikita Zimov ◽  
Anya Davydova ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Climate Impacts ◽  
Frozen Ground ◽  
River Bank ◽  
Permafrost Thaw ◽  
Degradation Rates ◽  
Kolyma River

<p>Soil temperatures in permafrost (i.e. perennially frozen ground) are rising globally. The increasing temperatures accelerate permafrost thaw and release of organic carbon, that has been locked in permafrost soils since the last glacial period, to the contemporary carbon cycle. The potential remineralisation of organic carbon to greenhouse gases can contribute to further climate warming. Particulate organic carbon (POC) in the Kolyma River is older than dissolved organic carbon (DOC) thus serves as a good tracer for abrupt permafrost thaw (i.e. river bank erosion and thermokarst) that dominantly releases old POC. While dissolved organic carbon (DOC) mobilised from the old Yedoma outcrops on the banks of the Kolyma River is shown to be highly labile, vulnerability of POC to biodegradation is not yet known. In this study we aim to constrain degradation rates for POC in the Kolyma River. To capture seasonal variability of the POC pool and its degradation rate the incubation was conducted both during the spring freshet and in late summer (2019 and 2018, respectively). We incubated whole-water samples over 9 to 15 days and quantified POC (and DOC) loss over time, as well as dissolved inorganic carbon (DIC). The incubation was carried out in the dark. We also tracked changes in POC composition and age with carbon isotopes (d<sup>13</sup>C-OC, d<sup>13</sup>C-DIC, ∆<sup>14</sup>C). Preliminary results from 2018 suggest a decrease in POC concentrations of up to 30 % while those of DOC decrease by up to 11 %. The rate of POC degradation is nearly three times faster than DOC though the absolute amounts of DOC are in turn higher than those of POC (< 1 mg L<sup>-1</sup> for POC and ~3 mg L<sup>-1</sup> for DOC). Furthermore, the changes in d<sup>13</sup>C of POC, DOC and DIC suggest ongoing microbial degradation and conversion of organic carbon into inorganic carbon. These first estimates show that POC degrades fairly rapidly while transported in the Kolyma River. A better understanding of POC degradation along lateral flow paths is critical for improving our knowledge of permafrost thaw and its possible climate impacts in the future.</p>

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