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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 307 records · Page 17

Identification of Novel Microcystins Using High-Resolution MS and MS n with Python Code

Cyanotoxins called microcystins (MCs) are highly toxic and can be present in drinking water sources. Determining the structure of MCs is paramount because of its effect on toxicity. Though over 300 MC congeners have been discovered, many remain unidentified. In this work, a method is described for the putative identification of MCs using liquid chromatography (LC) coupled with high-resolution (HR) Orbitrap mass spectrometry (MS) and a new bottom-up sequencing strategy. Maumee River water samples were collected during a harmful algal bloom and analyzed by LC–MS with simultaneous HRMS and MS/MS. Unidentified ions with characteristic MC fragments (135 and 213 m/z) were recognized as possible novel MC congeners. An innovative workflow was developed for the putative identification of these ions. Python code was written to generate the potential structures of unidentified MCs and to assign ions after the fragmentation for structural confirmation. The workflow enabled the putative identification of eight previously reported MCs for which standards are not available and two newly discovered congeners, MC-HarR and MC-E(OMe)R.

54 ENVIRONMENTAL SCIENCES↗

Hyporheic Zone Microbiome Assembly Is Linked to Dynamic Water Mixing Patterns in Snowmelt-Dominated Headwater Catchments

We report that terrestrial and aquatic elemental cycles are tightly linked in upland fluvial networks. Biotic and abiotic mineral weathering, microbially mediated degradation of organic matter, and anthropogenic influences all result in the movement of solutes (e.g., carbon, metals, and nutrients) through these catchments, with implications for downstream water quality. Within the river channel, the region of hyporheic mixing represents a hot spot of microbial activity, exerting significant control over solute cycling. To investigate how snowmelt-driven seasonal changes in river discharge affect microbial community assembly and carbon biogeochemistry, depth-resolved pore water samples were recovered from multiple locations around a representative meander on the East River near Crested Butte, CO, USA. Vertical temperature sensor arrays were also installed in the streambed to enable seepage flux estimates. Snowmelt-driven high river discharge led to an expanding zone of vertical hyporheic mixing and introduced dissolved oxygen into the streambed that stimulated aerobic microbial respiration. These physicochemical processes contributed to microbial communities undergoing homogenizing selection, in contrast to other ecosystems where lower permeability may limit the extent of mixing. Conversely, lower river discharge conditions led to a greater influence of upwelling groundwater within the streambed and a decrease in microbial respiration rates. Finally, associated with these processes, microbial communities throughout the streambed exhibited increasing dissimilarity between each other, suggesting that the earlier onset of snowmelt and longer periods of base flow may lead to changes in the composition (and associated function) of streambed microbiomes, with consequent implications for the processing and export of solutes from upland catchments.

58 GEOSCIENCES↗

Nutrient supply controls the linkage between species abundance and ecological interactions in marine bacterial communities

Nutrient scarcity is pervasive for natural microbial communities, affecting species reproduction and co-existence. However, it remains unclear whether there are general rules of how microbial species abundances are shaped by biotic and abiotic factors. Here we show that the ribosomal RNA gene operon (rrn) copy number, a genomic trait related to bacterial growth rate and nutrient demand, decreases from the abundant to the rare biosphere in the nutrient-rich coastal sediment but exhibits the opposite pattern in the nutrient-scarce pelagic zone of the global ocean. Both patterns are underlain by positive correlations between community-level rrn copy number and nutrients. Furthermore, inter-species co-exclusion inferred by negative network associations is observed more in coastal sediment than in ocean water samples. Nutrient manipulation experiments yield effects of nutrient availability on rrn copy numbers and network associations that are consistent with our field observations. Based on these results, we propose a “hunger games” hypothesis to define microbial species abundance rules using the rrn copy number, ecological interaction, and nutrient availability.

59 BASIC BIOLOGICAL SCIENCES↗

Efficient electrocatalytic valorization of chlorinated organic water pollutant to ethylene

Electrochemistry can provide an efficient and sustainable way to treat environmental waters polluted by chlorinated organic compounds. However, the electrochemical valorization of 1,2-dichloroethane (DCA) is currently challenged by the lack of a catalyst that can selectively convert DCA in aqueous solutions into ethylene. Here, in this work, we report a catalyst comprising cobalt phthalocyanine molecules assembled on multiwalled carbon nanotubes that can electrochemically decompose aqueous DCA with high current and energy efficiencies. Ethylene is produced at high rates with unprecedented ~100% Faradaic efficiency across wide electrode potential and reactant concentration ranges. Kinetic studies and density functional theory calculations reveal that the rate-determining step is the first C–Cl bond breaking, which does not involve protons—a key mechanistic feature that enables cobalt phthalocyanine/carbon nanotube to efficiently catalyse DCA dechlorination and suppress the hydrogen evolution reaction. The nanotubular structure of the catalyst enables us to shape it into a flow-through electrified membrane, which we have used to demonstrate >95% DCA removal from simulated water samples with environmentally relevant DCA and electrolyte concentrations.

Choi, Chungseok↗

Statistically Significant Evidence of a Release of Zinc from Pit 1 at the Lawrence Livermore National Laboratory Experimental Test Site 300 (90-Day Report)

Lawrence Livermore National Laboratory (LLNL) is submitting this 90-Day Report in accordance with Waste Discharge Requirements Order No. 93-100, Provision 4. This letter report is provided in reference to several seven-day letters in which LLNL reported that ground water sample analytical results from monitoring wells Kl-05, Kl-08, Kl-09, and W-PITl-2326 indicated "statistically significant evidence of a release" of zinc from LLNL's Site 300 Experimental Test Facility landfillPit 1 (Figure 1).

54 ENVIRONMENTAL SCIENCES↗

Magnetic Nanoparticle Extraction of Lithium from Produced Waters: CRADA 483 [Abstract only]

In this project, we will synthesize, evaluate, and screen a set of new sorbents that have high capacity and selectivity for lithium. Sorbent performance will be evaluated by conducting Li extraction tests with produced water samples supplied by ConocoPhillips Company, Moselle Technologies, and Cascade Natural Resources. The best performing of these sorbents based on Li uptake capacity and selectivity will be produced as a magnetic nanoparticle and subjected to extended cycle testing in our laboratory bench-scale magnetic separator system. Moselle has acquired an exclusive license to the background IP associated with this magnetic nanoparticle mineral extraction technology and wishes to foster implementation of the technology in the oil & gas industry through this CRADA. Moselle will support PNNL in the design of a commercial-scale magnetic separator system tailored for lithium production. The goal is to collect sufficient information to support a decision by our industry partners to invest in a subsequent field demonstration at one of our partner’s field sites as a prerequisite to advancing this technology towards commercialization.

36 MATERIALS SCIENCE↗

Linking Spatiotemporal Biological Data to Predict Harmful Algal Blooms

Cyanobacterial Harmful Algal Blooms (cHABs) have significant impacts on an affected region’s economy, ecology, and human health. The blooms can release toxins that kill fish and poison water for people and animals. The global adverse effects of cHABs are exacerbated by the consequences of climate change and increased pollution. Though the phenomena are well documented, scientists’ efforts to mitigate the damage are hampered by insufficient predictive models and incomplete granular knowledge of cHAB community structure. With a goal of leveraging bioinformatics and machine learning tools to better understand and predict cHABs, we are first exploring water sample data sets. Using nearly four thousand samples from the National Center for Biotechnology Information Sequence Read Archive (NCBI-SRA) across 16 years with latitude and longitude embedded in the metadata, we mapped the location of the samples onto a Lake Erie shape file. We combined information about location, date, and community taxa in the NCBI samples to discover factors that determine cHAB features. The data are separated into three distinct zones, with the majority pooled at the southwest end of the lake and occurring in 2017. The samples are rich in biological data; our next steps are to carry out whole genome sequence analysis and use the community profiles as part of our predictive machine learning model.

59 BASIC BIOLOGICAL SCIENCES↗

Genomic Characterization and Wetland Occurrence of a Novel Campylobacter Isolate from Canada Geese

Populations of resident, non-migratory Canada geese are rapidly increasing. Canada geese are known to transmit viral and bacterial diseases, posing a possible threat to human health. The most prevalent pathogens vectored by geese are Campylobacter species, yet the current understanding of the identity and virulence of these pathogens is limited. In our previous study, we observed a high prevalence of Campylobacter spp. in the Banklick Creek wetland—a constructed treatment wetland (CTW) located in northern KY (USA) used to understand sources of fecal contamination originating from humans and waterfowl frequenting the area. To identify the types of Campylobacter spp. found contaminating the CTW, we performed genetic analyses of Campylobacter 16s ribosomal RNA amplified from CTW water samples and collected fecal material from birds frequenting those areas. Our results showed a high occurrence of a Campylobacter canadensis-like clade from the sampling sites. Whole-genome sequence analyses of an isolate from Canada goose fecal material, called MG1, were used to confirm the identity of the CTW isolates. Further, we examined the phylogenomic position, virulence gene content, and antimicrobial resistance gene profile of MG1. Lastly, we developed an MG1-specific real-time PCR assay and confirmed the presence of MG1 in Canada goose fecal samples surrounding the CTW. Our findings reveal that the Canada goose-vectored Campylobacter sp. MG1 is a novel isolate compared to C. canadensis that possesses possible zoonotic potential, which may be of human health concern.

59 BASIC BIOLOGICAL SCIENCES↗

Bismuth Subcarbonate Decorated Reduced Graphene Oxide Nanocomposite for the Sensitive Stripping Voltammetry Analysis of Pb(II) and Cd(II) in Water

In this paper, bismuth subcarbonate (BiO)2CO3-reduced graphene oxide nanocomposite incorporated in Nafion matrix ((BiO)2CO3-rGO-Nafion) was synthesized and further applied, for the first time, in the sensitive detection of Pb(II) and Cd(II) by square-wave anodic stripping voltammetry (SWASV). The as-synthesized nanocomposites were characterized by energy-dispersive spectroscopy (EDS), Raman spectroscopy, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). (BiO)2CO3 composite plays a key role in the improvement of the detection sensitivity, which can form multicomponent alloy with cadmium and lead. Additionally, the unique structure of rGO can enlarge the surface area and provide abundant active sites. Moreover, Nafion incorporation in the nanocomposite can effectively increase the adhesion and mechanical strength of the film, and further improve the preconcetration ability due to the cation-exchange capacity of its abundant sulfonate groups. As expected, the (BiO)2CO3-rGO/Nafion nanocomposite-modified glassy carbon electrode ((BiO)2CO3-rGO-Nafion/GCE) achieved low detection limits of 0.24 μg/L for Pb(II) and 0.16 μg/L for Cd(II), in the linear range of 1.0–60 μg/L, and showed some excellent performance, such as high stability, good selectivity, and sensitivity. Finally, synthetic water samples were prepared and further used to verify the practicability of the (BiO)2CO3-rGO-Nafion/GCE with satisfactory results.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

A method of isolating organic compounds present in water

Water sample is passed through a column containing macroreticular resin, which absorbs only nonionic organic compounds. These compounds are selectively separated using aqueous eluents of varying pH, or completely exuded with small amount of an organic eluent.

Calder, G. V.↗

Development of a tape transport bacterial detection system

The feasibility of a tape transport chemiluminescence system for bacterial monitoring of regenerated water was demonstrated using a manually operated laboratory breadboard. The principle of detection is based on measuring the increase in chemiluminescence produced by the catalytic action of bacterial porphyrins on a luminol-hydrogen peroxide mixture. Viable organisms are distinguished from nonviable by comparing the signals of incubated and unincubated water samples. Using optimized protocols, sensitivities were obtained with 400 ml suspensions of E. coli and Cl. sporogenes. The sensitivity of the unincubated cycle E. coli (aerobe) was found to be 30 to 35 cells/m1, and that of the Cl. sporogenes (anaerobe) was 1000 to 10,000 cells/m1. The lower sensitivity toward Cl. sporogenes is attributed to several factors, namely the lower cytochrome content, the tendency to sporulate, long lag periods and the lower growth rate of Clostridia in general. The operational procedures used for processing the incubated and unincubated samples involved the following sequence: (1) concentrating the sample by filtration through a membrane filter, (2) washing with Dextrose-Thioglycollate Broth (3) incubating (0 to 4 hrs as required), (4) washing with 4M Urea, and (5) reacting with reagent in front of a photomultiplier tube. The signal output was recorded on a strip chart recorder.

Witz, S.↗

Alleged Mercury Discharge by the Lewis Research Center

Water sample analysis, site visits, and effluent reports are examined in an attempt to identify the sources contributing to mercury pollution of the Great Lakes. Two sources were identified, Lewis Research Center and Dow Chemical of Canada. Tests were made during a period from April to September 1970.

Rosenbluum, L.↗

Remote measurement of water color in coastal waters

An investigation was conducted to develop procedure to obtain quantitative values for chlorophyll and turbidity in coastal waters by observing the changes in spectral radiance of the backscattered spectrum. The technique under consideration consists of Examining Exotech model 20-D spectral radiometer data and determining which radiance ratios best correlated with chlorophyll and turbidity measurements as obtained from analyses of water samples and sechi visibility readings. Preliminary results indicate that there is a correlation between backscattered light and chlorophyll concentration and secchi visibility. The tests were conducted with the spectrometer mounted in a light aircraft over the Mississippi Sound at altitudes of 2.5K, 2.8K and 10K feet.

Weldon, J. W.↗

The application of laser-Raman light scattering to the determination of sulfate in sea and estuarine waters

Laser-Raman light scattering is a technique for determining sulfate concentrations in sea and estuarine waters with apparently none of the interferences inherent in the gravimetric and titrametric methods. The Raman measurement involved the ratioing of the peak heights of an unknown sulfate concentration and a nitrate internal standard. This ratio was used to calculate the unknown sulfate concentration from a standard curve. The standard curve was derived from the Raman data on prepared nitrate-sulfate solutions. At the 99.7% confidence level, the accuracy of the Raman technique was 7 to 8.6 percent over the concentration range of the standard curve. The sulfate analyses of water samples collected at the mouth of the James River, Hampton, Virginia, demonstrated that in most cases sulfate had a constant concentration relative to salinity in this area.

Bandy, A. R.↗

Monitoring physical and chemical parameters of Delaware Bay waters with an ERTS-1 data collection platform

The author has identified the following significant results. Evaluation of the probe performances during the initial phase indicates that the dissolved oxygen sensor available as part of the package is not sufficiently reliable for long term operation. The turbidity probe requires frequent visits to the site to maintain it in proper operating condition. The cost of these visits would have to be weighed against the information obtained. The conductivity/salinity, temperature, pH, and depth indicators have worked extremely well over the course of the study. Monthly cleanings would maintain all these probes in top operating condition. Currently the accuracy of each measurement returned via satellite is being compared to the accuracy of the probe reading and water samples analyzed in the laboratory.

Klemas, V.↗

The application of large numbers of pleasure boats to collect synoptic sea-truth for ERTS-1 overpasses

The author has identified the following significant results. In order to interpret and annotate current circulation and suspended sediment concentration maps derived from ERTS-1 digital tapes, the University of Delaware has been collecting water samples and other data from boats and helicopters. In order to increase the number of samples at the exact time of the ERTS-1 pass over Delaware Bay, pleasure craft were organized to obtain samples of the entire test site. On the ERTS-1 pass of July second, scientists were stationed at three public boat launches along the Bay to hand out sampling packets to interested boaters. The packets contained two litre sampling bottles, a map, data card, and a pen. The boaters were asked to fill the two bottles between 11 and 11:15 a.m., mark their location on the map, and fill out the data card. Forty-nine packets were handed out of which 40 were returned (82%). Only four of the 40 were not in the alloted time range. This gave 36 real time data points covering approximately 30 nautical miles. The samples are being analyzed for sediment concentration, particle size, and salinity. Participating boaters will receive a copy of an ERTS image of the Delaware Bay and a summary report of the project. Because of the success of the project, future use of pleasure boaters is being planned.

Klemas, V.↗

Measurement of Raman spectra of H2O and SO4(-) in seawater

A study of applying laser Raman spectroscopy to remote sensing of the sulfate ion in sea water is in progress. The SO4 Raman spectrum has been obtained from true sea water samples in the laboratory using a CW laser Raman spectrometric system. Radiometric calculations indicate the feasibility of obtaining usable SO4 Raman signals in a field experiment. One of serious difficulties expected in the field experiment would be from fluorescence of phytoplankton and organics.

Houghton, W. M.↗

Spectral reflectance signatures of coastal pollutants

The author has identified the following significant results. Remote sensing from satellites and aircraft was combined with ground truth collected from ships in an attempt to classify coastal and estuarine water types by their spectral reflectance signatures. During ocean waste disposal operations 40 miles off the Delaware coast, water samples were collected and spectroradiometric measurements conducted in the field to provide ground truth for aircraft and LANDSAT overpasses with multispectral scanners.

Klemas, V.↗