Multi-isotope (15N, 18O and 13C) indicators of sources and fate of nitrate in the upper stream of Chaobai River, Beijing, China

2014 ◽  
Vol 16 (11) ◽  
pp. 2644-2655 ◽  
Author(s):  
Cai Li ◽  
Yongbin Jiang ◽  
Xinyue Guo ◽  
Yang Cao ◽  
Hongbing Ji
Keyword(s):  
Water Chemistry ◽  
Carbon Isotopes ◽  
North China ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Beijing China

Dual isotopes of nitrate (15N and 18O) and carbon isotopes of dissolved inorganic carbon (13C) together with water chemistry were used to identify the sources and fate of nitrate in the upper stream of Chaobai River, north China.

scholarly journals Evaluating Dissolved Inorganic Carbon Cycling in a Forested Lake Watershed Using Carbon Isotopes

Radiocarbon ◽  
1992 ◽  
Vol 34 (3) ◽  
pp. 636-645 ◽  
Author(s):  
Ramon Aravena ◽  
S. L. Schiff ◽  
S. E. Trumbore ◽  
P. J. Dillon ◽  
Richard Elgood
Keyword(s):  
Isotopic Composition ◽  
Carbon Isotopes ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Carbon Isotopic Composition ◽  
Isotopic Fractionation ◽  
Early Spring ◽  
Late Winter ◽  
Isotope Pattern ◽  
Carbon Isotopic

Dissolved inorganic carbon (DIC) is the main acid buffer in forested lake watersheds in Canada. We used carbon isotopes (13C, 14C) to evaluate the production and cycling of DIC in an acid-sensitive lake watershed of the Precambrian Shield. Soil CO2, groundwater and stream DIC were characterized chemically and isotopically. Soil CO2 concentration profiles reflect both changes in production and in losses due to diffusion. δ13C soil CO2 profiles (δ13C values of −23‰ in summer, slightly enriched during the fall and −25%‰ during the winter) are a reflection of the isotopic composition of the sources and changes in isotopic fractionation due to diffusion. Carbon isotopic composition (13C, 14C) of the groundwater and stream DIC clearly indicate that weathering of silicates by soil CO2 is the main source of DIC in these watersheds. 14C data show that, in addition to recent groundwater, an older groundwater component with depleted 14C activity is also present in the bedrock. The carbon isotope pattern in the groundwater also implies that, besides the main springtime recharge events, contributions to the groundwater may also occur during late winter/early spring.

Dissipation of Permethrin in Limnocorrals

1985 ◽  
Vol 42 (1) ◽  
pp. 70-76 ◽  
Author(s):  
K. R. Solomon ◽  
J. Y. Yoo ◽  
D. Lean ◽  
N. K. Kaushik ◽  
K. E. Day ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Water Chemistry ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Secchi Disk ◽  
Secchi Disk Depth ◽  
Southern Ontario ◽  
First Order ◽  
First Order Kinetics ◽  
Rate Of Dissipation

Permethrin (3-phenoxybenzyl(1RS)-cis,trans-3-(2,2-dimethy[-3-dichlorovinyl)-2,2-dimethylcyciopropanecarboxylate) applied to approximately 100-m3 enclosures (limnocorrals) in a small mesotrophic lake in Southern Ontario (47°51′25″N; 77°25′30″W) at concentrations of 500, 50, 5, and 0.5 μ∙L−1 dissipated from the water rapidly and approximated first-order kinetics in the first 8–12 d. Time taken for 50 and 90% dissipation ranged from 1.65 and 3.65 d, respectively, at 0.5 μ∙L−1 to 3.5 and 6.75 d, respectively, at 50 μ∙L−1. Inter- and intra-seasonal replication of dissipation patterns was good. Rate of dissipation varied slightly with depth, normally being slower at greater depth. Absorption of permethrin to sediments was rapid, penetration shallow, and disappearance slow. Permethrin had no effect on water chemistry but there was an increase in the Secchi disk depth in the treated limnocorrals. Dissolved inorganic carbon decreased in all limnocorrals, including controls after treatment, suggesting precipitation of calcium carbonate which may act as a scavenging agent for permethrin in the water. Limnocorrals are a useful tool for evaluating the behavior of pesticides in the aquatic system.

scholarly journals Carbon isotopes of dissolved inorganic carbon reflect utilization of different carbon sources by microbial communities in two limestone aquifer assemblages

2016 ◽  
Author(s):  
Martin E. Nowak ◽  
Valérie F. Schwab ◽  
Cassandre S. Lazar ◽  
Thomas Behrendt ◽  
Bernd Kohlhepp ◽  
...  
Keyword(s):  
Organic Matter ◽  
Microbial Communities ◽  
Carbon Isotopes ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Carbon Sources ◽  
Oxygen Depletion ◽  
C Isotopes ◽  
Abiotic Controls ◽  
Upper Aquifer

Abstract. Isotopes of dissolved inorganic carbon (DIC) are used to indicate both transit times and biogeochemical evolution of groundwaters. These signals can be complicated in carbonate aquifers, as both abiotic (i.e. carbonate equilibria) and biotic factors influence δ13C and 14C of DIC. We applied a novel graphical method for tracking changes in δ13C and 14C of DIC in two distinct aquifer complexes identified in the Hainich Critical Zone Exploratory (CZE), a platform to study how water transport links surface and shallow groundwaters in limestone and marlstone rocks in central Germany. For more quantitative estimates of contributions of different biotic and abiotic carbon sources to the DIC pool, we used the geochemical modelling program NETPATH, which accounts for changes in dissolved ions in addition to C isotopes. Although water residence times in the Hainich CZE aquifers based on hydrogeology are relatively short (years or less), DIC isotopes in the shallow, mostly anoxic, aquifer assemblage (HTU) were depleted in 14C compared to a deeper, oxic, aquifer complex (HTL). Carbon isotopes and chemical changes in the deeper HTL wells could be explained by interaction of recharge waters equilibrated with post-bomb 14C sources with carbonates. However, oxygen depletion and δ13C and 14C values of DIC below those expected from the processes of carbonate equilibrium alone indicate dramatically different biogeochemical evolution of waters in the upper aquifer assemblage (HTU wells). Changes of 14C and 13C in the upper aquifer complexes result from a number of biotic and abiotic processes, including oxidation of 14C depleted OM derived from recycled microbial carbon and sedimentary organic matter as well as water rock interactions. The microbial pathways inferred from DIC isotope shifts and changes in water chemistry in the HTU wells were supported by comparison with in situ microbial community structure based on 16S rRNA analyses. Our findings demonstrate the large variation in the importance of biotic as well as abiotic controls on 13C and 14C of DIC in closely related aquifer assemblages. Further, they support the importance of subsurface derived carbon sources like DIC for chemolithoautotrophic microorganisms as well as rock-derived organic matter for supporting heterotrophic groundwater microbial communities and indicate that even shallow aquifers have microbial communities that use a variety of subsurface derived carbon sources.

Carbon isotopes in dissolved inorganic carbon as tracers of carbon sources in karst waters of the Plitvice Lakes, Croatia

2020 ◽  
pp. SP507-2020-49 ◽  
Author(s):  
Andreja Sironić ◽  
Ines Krajcar Bronić ◽  
Nada Horvatinčić ◽  
Jadranka Barešić ◽  
Damir Borković ◽  
...  
Keyword(s):  
Carbon Isotopes ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Carbon Sources ◽  
Karst Waters ◽  
Plitvice Lakes
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