Final report on isotope tracer investigations in the Forebay of the Orange County groundwater basin.

Davisson, M. Lee; Woodside, Greg

doi:10.2172/15013774

Cited by 5 publications

(5 citation statements)

References 26 publications

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“…Isoprenoids were synthesized as described in the SI methods section with minor modifications of previous reports. 14,[16][17][18] Sequences in the SI were used to generate recombinant proteins in the vector backbone of pET24a (Genscript). Overexpression of proteins was conducted in E. coli strains C41 (UppS) or C43 (WbaP, WecA, and WecP).…”

Section: Generalmentioning

confidence: 99%

General Utilization of Fluorescent Polyisoprenoids with Sugar Selective Phosphoglycosyltransferases

et al. 2019

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The protective surfaces of bacteria are comprised of polysaccharides and are involved in host invasion and colonization, host immune system evasion, as well as antibacterial resistance. A major barrier to our fundamental understanding of these complex surface polysaccharides lies in the tremendous diversity in glycan composition among bacterial species. The polyisoprenoid bactoprenyl phosphate (or undecaprenyl phosphate) is an essential lipid carrier necessary for early stages of glycopolymer assembly. Because of the ubiquity of bactoprenyl phosphate in these critical processes, molecular probes appended to this lipid carrier simplify identification of enzymatic roles during polysaccharide bioassembly. A limited number of these probes exist in the literature or have been assessed with such pathways, and the limits of their use are not currently known. Herein, we devise an efficient method for producing fluorescently modified bactoprenyl probes. We further expand our previous efforts utilizing 2-nitrileaniline, and additionally prepare nitrobenzoxadizol tagged bactoprenyl phosphate for the first time. We then assess enzyme promiscuity of these two probes utilizing four well characterized initiating phosphoglycosyltransferases: CPS2E (Streptococcus pneumoniae), WbaP (Salmonella enterica), WecA (Escherichia coli) and WecP (Aeromonas hydrophilia). Both probes serve as substrates for these enzymes and could be readily used to investigate a wide range of bacterial glycoassembly pathways. Interestingly, we have also identified unique solubility requirements for the

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Section: Generalmentioning

confidence: 99%

General Utilization of Fluorescent Polyisoprenoids with Sugar Selective Phosphoglycosyltransferases

et al. 2019

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“…The latter included gas tracer experiments using sulfur hexafluoride (SF 6 ) and xenon isotopes ( 124 Xe, 129 Xe, 136 Xe) and experiments of "opportunity" using the stable isotopes of water. All data and experimental details can be found in Davisson et al (2004).…”

Section: Introductionmentioning

confidence: 99%

Geochemical Imaging of Flow Near an Artificial Recharge Facility, Orange County, California

Clark¹,

Hudson²,

Davisson³

et al. 2004

Groundwater

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Critical for the management of artificial recharge operations is detailed knowledge of ground water dynamics near spreading areas. Geochemical tracer techniques including stable isotopes of water, tritium/helium–3 (T/3He) dating, and deliberate gas tracer experiments are ideally suited for these investigations. These tracers were used to evaluate flow near an artificial recharge site in northern Orange County, California, where ∼2.5 × 108 m3 (200,000 acre‐feet) of water are recharged annually. T/3He ages show that most of the relatively shallow ground water within 3 km of the recharge facilities have apparent ages < 2 years; further downgradient apparent ages increase, reaching > 20 years at ∼6 km. Gas tracer experiments using sulfur hexafluoride and xenon isotopes were conducted from the Santa Ana River and two spreading basins. These tracers were followed in the ground water for more than two years, allowing subsurface flow patterns and flow times to be quantified. Results demonstrate that mean horizontal ground water velocities range from < 1 to > 4 km/year. The leading edges of the tracer patch moved at velocities about twice as fast as the center of mass. Leading edge velocities are important when considering the potential transport of microbes and other “time sensitive” contaminants and cannot be determined easily with other methods. T/3He apparent ages and tracer travel times agreed within the analytical uncertainty at 16 of 19 narrow screened monitoring wells. By combining these techniques, ground water flow was imaged with time scales on the order of weeks to decades.

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“…Artificial recharge may occur at temperatures different from the local average water table temperature due to seasonal recharging activities and heating of water in spreading basins. For example, temperatures of surface water used for artificial recharge in LAB can vary from 10 to 35 °C annually (44). It is also likely that many well water samples are mixtures of naturally recharged and artificially recharged waters.…”

Section: Resultsmentioning

confidence: 99%

Impact of Artificial Recharge on Dissolved Noble Gases in Groundwater in California

Cey

Hudson

Moran

et al. 2008

Environ. Sci. Technol.

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Dissolved noble gas concentrations in groundwater can provide valuable information on recharge temperatures and enable 3H-3He age-dating with the use of physically based interpretive models. This study presents a large (905 samples) data set of dissolved noble gas concentrations from drinking water supply wells throughout California, representing a range of physiographic, climatic, and water management conditions. Three common interpretive models (unfractionated air, UA; partial re-equilibration, PR; and closed system equilibrium, CE) produce systematically different recharge temperatures or ages; however, the ability of the different models to fit measured data within measurement uncertainty indicates that goodness-of-fit is not a robust indicator for model appropriateness. Therefore caution is necessary when interpreting model results. Samples from multiple locations contained significantly higher Ne and excess air concentrations than reported in the literature, with maximum excess air tending toward 0.05 cm3 STP g(-1) (deltaNe approximately 400%). Artificial recharge is the most plausible cause of the high excess air concentrations. The ability of artificial recharge to dissolve greater amounts of atmospheric gases has important implications for oxidation-reduction dependent chemical reactions. Measured gas concentration ratios suggest that diffusive degassing may have occurred. Understanding the physical processes controlling gas dissolution during groundwater recharge is critical for optimal management of artificial recharge and for predicting changes in water quality that can occur following artificial recharge.

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Final report on isotope tracer investigations in the Forebay of the Orange County groundwater basin.

Cited by 5 publications

References 26 publications

General Utilization of Fluorescent Polyisoprenoids with Sugar Selective Phosphoglycosyltransferases

General Utilization of Fluorescent Polyisoprenoids with Sugar Selective Phosphoglycosyltransferases

Geochemical Imaging of Flow Near an Artificial Recharge Facility, Orange County, California

Impact of Artificial Recharge on Dissolved Noble Gases in Groundwater in California

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