Phosphate Uptake by Cyanobacteria Is Associated with Kinetic Fractionation of Phosphate Oxygen Isotopes

2018 ◽  
Vol 3 (2) ◽  
pp. 233-239 ◽  
Author(s):  
Hagar Lis ◽  
Tal Weiner ◽  
Frances D. Pitt ◽  
Nir Keren ◽  
Alon Angert
Keyword(s):  
Oxygen Isotopes ◽  
Phosphate Uptake ◽  
Kinetic Fractionation

Kinetic fractionation of carbon and oxygen isotopes during BaCO3 precipitation

2020 ◽  
Vol 280 ◽  
pp. 395-422 ◽  
Author(s):  
Ziv Sade ◽  
Ruth Yam ◽  
Aldo Shemesh ◽  
Itay Halevy
Keyword(s):  
Oxygen Isotopes ◽  
Carbon And Oxygen Isotopes ◽  
Kinetic Fractionation

scholarly journals Isotopic Tracing of Perchlorate Sources in the Environment

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Mengnan Zhang ◽  
Xiaoqian Li ◽  
Xuxue Cheng ◽  
Xinfeng Wang ◽  
Mian Song ◽  
...  
Keyword(s):  
Oxygen Isotopes ◽  
Formation Mechanisms ◽  
Primary Concern ◽  
Source Information ◽  
Hormone Production ◽  
Chlorine Isotopes ◽  
Isotopic Tracing ◽  
Oxygen Isotopic ◽  
Kinetic Fractionation ◽  
Trace Concentrations

Perchlorate (ClO4−) is an emerging persistent pollutant that is ubiquitous in the environment at trace concentrations. Perchlorate ingestion poses a risk to human health because it interferes with thyroidal hormone production. The identification of perchlorate sources in groundwater is a primary concern. Chlorine and multi-oxygen isotopic tracing of perchlorate (δ37Cl, 36Cl/Cl, δ18O, and Δ17O) can provide a unique tool for identifying the origin and transport of perchlorate in groundwater. Along with the kinetic fractionation of chlorine and oxygen isotopes, the Δ17O value, 36Cl/Cl ratio, and ε18O/ε37Cl (the fractionation coefficient of oxygen and chlorine isotopes) are constant, potentially indicating the biodegradation of perchlorate, without disguising its source information. Therefore, comprehensive characterization of stable chlorine and poly-oxygen isotopes is expected to provide direct evidence for identifying the source of perchlorate in groundwater. However, further studies are needed to increase the amount of isotopic data of different perchlorate sources, to make the end-member model available to broader regions. It is critically important to understand the range of values and differences of isotopes among natural perchlorate sources and the perchlorate formation mechanisms.

Sulfur and oxygen isotopic composition of sulfates at two saline sites in southern Alberta

1993 ◽  
Vol 73 (4) ◽  
pp. 633-637 ◽  
Author(s):  
J. J. Miller ◽  
G. J. Beke ◽  
S. Pawluk ◽  
H. R. Krouse
Keyword(s):  
Isotopic Composition ◽  
Key Words ◽  
Oxygen Isotopes ◽  
Sulfur Isotopes ◽  
Oxygen Isotopic Composition ◽  
Southern Alberta ◽  
Oxygen Isotopic ◽  
Preliminary Study ◽  
Kinetic Fractionation ◽  
Isotope Analyses

Possible sources of SO4 in soil, drift and bedrock at two saline sites in southern Alberta were investigated using sulfur and oxygen isotope analyses. Slight differences (0.6–5.2 per mil) between δ34S values of SO4 and insoluble S in the geologic material were attributed to kinetic fractionation during oxidation of organic S. Negative δ18O values of SO4 in the shallow (<6 m) bedrock, drift and soil reflected oxidation of reduced S. In contrast, positive δ18O values in the deep (>6 m) bedrock indicated sulfate reduction. The exact source of SO4 could not be determined in this preliminary study. The isotope approach, however, shows promise and warrants more detailed study. Key words: Salinization, sulfates, sulfur isotopes, oxygen isotopes

Changes of Ionic and Oxygen Isotopic Composition of the Snowpack at the Glacier Austre Okstindbreen, Norway, 1995

1998 ◽  
Vol 29 (1) ◽  
pp. 1-20 ◽  
Author(s):  
Peter Raben ◽  
Wilfred H. Theakstone
Keyword(s):  
Isotopic Composition ◽  
Sea Level ◽  
Oxygen Isotopes ◽  
Oxygen Isotopic Composition ◽  
Isotopic Ratios ◽  
Vertical Variations ◽  
Oxygen Isotopic ◽  
The Difference ◽  
Liquid Precipitation ◽  
Different Altitudes

Marked vertical variations of ions and oxygen isotopes were present in the snowpack at the glacier Austre Okstindbreen during the pre-melting phase in 1995 at sites between 825 m and 1,470 m above sea level. As the first meltwater percolated from the top of the pack, ions were moved to a greater depth, but the isotopic composition remained relatively unchanged. Ions continued to move downwards through the pack during the melting phase, even when there was little surface melting and no addition of liquid precipitation. The at-a-depth correlation between ionic concentrations and isotopic ratios, strong in the pre-melting phase, weakened during melting. In August, concentrations of Na+ and Mg2+ ions in the residual pack were low and vertical variations were slight; 18O enrichment had occurred. The difference of the time at which melting of the snowpack starts at different altitudes influences the input of ions and isotopes to the underlying glacier.

Verification of anoxic phosphate uptake as the main biochemical mechanism of the “dephanox” process

1997 ◽  
Vol 35 (10) ◽  
pp. 87-94 ◽  
Author(s):  
R. Sorm ◽  
J. Wanner ◽  
R. Saltarelli ◽  
G. Bortone ◽  
A. Tilche
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Uptake Rate ◽  
Phosphate Uptake ◽  
Biochemical Mechanism ◽  
Batch Experiments ◽  
Batch Tests ◽  
Genetic Probes ◽  
Activated Sludge Systems ◽  
Removal System

The phenomenon of anoxic phosphate uptake with simultaneous denitrification was studied. For this purpose kinetic batch tests have been carried out by using the activated sludge samples from three modifications of nutrient removal activated sludge systems: two based on an anaerobic-anoxic-oxic (A2/O) system and a third on an anaerobic-oxic (A/O) system. The results showed significant differences in anoxic phosphate uptake rate between activated sludge which was alternatively exposed to anoxic conditions and activated sludge from the A/O arrangement. These differences were also accompanied by different denitrification rates. Simultaneously with batch experiments the microscopic observation of activated sludge samples was carried out. Neisser and Gram stained samples showed clear differences in shape, size and distribution of polyphosphate accumulating bacteria between A2/O and A/O Processes. Moreover, experiments performed using genetic probes confirmed the differences in microbiological composition of activated sludge samples from different nutrient removal system arrangements.

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