A5012211768- Atmospheric chemistry and aerosols
- Marine and coastal ecosystems
- Air Quality and Health Impacts
- Atmospheric aerosols and clouds
- Air Quality Monitoring and Forecasting
- Isotope Analysis in Ecology
- Geology and Paleoclimatology Research
- Geochemistry and Elemental Analysis
- Water Quality and Pollution Assessment
- Atmospheric and Environmental Gas Dynamics
- Carbon Nanotubes in Composites
- Marine Biology and Ecology Research
- Fermentation and Sensory Analysis
- Thermal and Kinetic Analysis
- Heavy metals in environment
- Radioactivity and Radon Measurements
- Heavy Metal Exposure and Toxicity
- Smart Materials for Construction
- Iron oxide chemistry and applications
- Tree-ring climate responses
- Graphite, nuclear technology, radiation studies
- Mathematics Education and Teaching Techniques
- Metabolomics and Mass Spectrometry Studies
- Genetics, Bioinformatics, and Biomedical Research
- Horticultural and Viticultural Research
Central Washington University
2007-2024
Nord University
2024
California Institute of Technology
1998-2000
Atmospheric deposition of trace elements and isotopes (TEI) is an important source metals to the open ocean, impacting TEI budgets distributions, stimulating oceanic primary productivity, influencing biological community structure function. Thus, accurate sampling aerosol TEIs a vital component ongoing GEOTRACES cruises, standardized analysis procedures allow comparison data from different sites investigators. Here, we report results intercalibration study by seventeen laboratories for...
Abstract This work presents iron isotope data in the western equatorial Pacific. Marine aerosols and top core margin sediments display a slightly heavy Fe isotopic composition ( δ 56 Fe) of 0.33 ± 0.11‰ (2SD) 0.14 0.07‰, respectively. Samples reflecting influence Papua New Guinea runoff (Sepik River Rabaul volcano water) are characterized by crustal values. In seawater, is mainly supplied particulate form found with between −0.49 0.34 0.07‰. The seems to be brought transported across...
Atmospheric deposition of iron (Fe) to certain regions the oceans is an important nutrient source Fe biota, and ability biota uptake dependent on speciation Fe. Therefore understanding in atmosphere critical role as a surface ocean waters. Labile ferrous (Fe(II)) concentrations well total for other trace metals, cations, anions were determined over Arabian Sea two nonconsecutive months during 1995. Ambient aerosol samples collected Indian Ocean intermonsoon southwest monsoon seasons Sea....
Ambient aerosol samples were collected over the tropical northern Atlantic Ocean during month of April 1996 onboard R/V Seward Johnson . Dichotomous high‐volume collector analyzed for ferrous iron immediately after collection, while trace metals, anions, and cations determined upon return to laboratory. Data are with aid enrichment factor, principal component, weighted multiple linear regression analyses. Average mineral concentrations amounted 19.3±16.4 μg m −3 whereby chemical...
Mineral aerosol deposition is the dominant source of iron to open ocean. Soil typically insoluble and understanding atmospheric processes that convert more soluble forms observed over oceans crucial. In this paper, we model several proposed for conversion Fe(III) Fe(II), compare with cruise observations. The comparisons show results in similar averaged magnitudes solubility as measured during 8 cruises 2001–2003. Comparisons cases including cloud, SO 2 hematite processing are better than...
Despite its importance for the global oceanic nitrogen (N) cycle, considerable uncertainties exist about N fluxes of Arabian Sea. On basis our recent measurements during German Sea Process Study as part Joint Global Ocean Flux (JGOFS) in 1995 and 1997, we present estimates various sources sinks such atmospheric dry wet depositions aerosols, pelagic denitrification, nitrous oxide (N 2 O) emissions, advective input from south. Additionally, estimated burial deep sea sedimentary shelf...
The oxidation state of four transition metals (Fe, Mn, Cu, and Cr) in cloudwater has been investigated during several cloud events at Whiteface Mountain (NY), one event San Pedro Hill (CA), fog Bakers-field (CA). Samples were collected immediately analyzed for the states metals: Fe(II) [44 measurements], Cu(I) [30 Mn(IV) [27 Cr(III) [3 measurements]. Extreme care was taken to minimize contamination interferences when measuring these states. Par-ticulate dissolved concentrations also...
Wine fraud leaves wineries vulnerable to damage in reputation and potential lost revenue. To reduce this risk for wines from Washington State (WA), USA, advanced analytical instrumentation statistical methods were employed geographically classify 133 4 major wine producing regions, including 70 WA. Analyses of 37 elements 2 water isotopes performed with Triple Quadrupole Inductively Coupled Plasma Mass Spectrometry Cavity Ring-Down Spectroscopy, respectively. Linear discriminant analysis...
Ambient aerosol samples were collected over the northern Indian Ocean during two 1 month‐long research cruises (German R/V Meteor ) that took place intermonsoon (May) and SW monsoon (July/August) of 1995. A high volume small collectors used to collect samples, which subsequently analyzed for ferrous iron, 32 elements, anions cations. The present paper focuses on bulk material, ions, while utilizing some trace metal data presented in more detail our previous [ Siefert et al. , 1999]. Data are...
The ultrafine size fraction of ambient particles (ultrafine [UFP], diameter < 100 nm) has been identified as being particularly potent in their adverse health effects, yet, the detailed mechanisms for why UFP display such distinctive toxicity are not well understood. In present study, mitochondria were exposed to while monitoring mitochondrial electron transport chain (ETC) activity a model system biochemical toxicity. samples collected rural and urban environments, chemically characterized...
Ambient aerosol samples were collected over the Arabian Sea during month of March 1997, aboard German R/V Sonne , as part Joint Global Ocean Flux Study (JGOFS) project. This is third study in a series analogous measurements taken different seasons monsoon. Dichotomous high‐volume collector analyzed for ferrous iron immediately after collection, while trace metals, anions, and cations determined upon return to laboratory. The main crustal component was geochemically well represented by...
Ambient aerosol samples were collected over the Arabian Sea during month of March 1997, aboard German R/V Sonne , as part JGOFS project (Joint Global Ocean Flux Study). This is third study in a series analogous measurements taken different seasons monsoon. Dichotomous high volume collector analyzed for anions and cations upon return to laboratory. Anthropogenic pollutant concentrations larger first cruise, when air masses originated Indian subcontinent. Total NSS‐SO 4 2− amounted 2.94 ± 1.06...
Mineral aerosol deposition is recognized as the dominant source of iron to open ocean and solubility in dust highly variable, with measurements ranging from 0.01–80%. Global models have difficulty capturing observed variations solubility, ignored dependence on size. We introduce two idealized physical estimate size mineral solubility: a diffusion‐controlled model surface‐area‐controlled model. These produce differing time‐ space‐varying maps for Fe Al given age at deposition, size‐resolved...
Within open‐ocean regions where excess macronutrients are present, phytoplankton growth is limited by the bioavailability of iron supplied to these areas primarily within atmospheric aerosols crustal origin. However, processes that control abundance biologically accessible in largely unknown. Here we show dissolution ferrihydrite, a surrogate iron(oxy)hydroxide phase found waters, enhanced presence methanesulfinic acid (MSIA, CH 3 SO 2 H, dimethylsulfide (DMS) oxidation intermediate)...
Iron contained in dust-derived aerosol particles deposited into remote oceans is essential for phytoplankton productivity, which controls photosynthesis rate and the uptake release of climate forcing gases. Understanding chemical mechanisms that control iron bioavailability, is, its speciation, therefore crucial global predictions. In present study, photoredox chemistry marine atmospheric was investigated by using ferrihydrite as a surrogate phase presence dimethyl sulfide (DMS) derived...
The quality of wines can be assessed both from chemical/biological tests and sensory (which rely mainly on human experts). Determining which is the subset to used a difficult problem. Each test has its own contribution for predicting and, in addition, cost. We use our database, consisting 32 wine characteristics applied 180 samples. In addition we labels assigned by expert. To extent knowledge, this first study kind Washington State, also general include cost minimization measurements as...
Abstract. This study presents aerosol iron isotopic compositions (δ56Fe) in Western and Central Equatorial Tropical Pacific Ocean. Aerosols supply (Fe), a critical element for marine primary production, to the open ocean. Particulate aerosols, > 1 µm, were sampled during EUCFe cruise (RV Kilo Moana, PI: J. W. Murray, 2006). One sample was isotopically lighter than crust (δ56Fe=-0.16 ± 0.07 ‰, 95 % confidence interval), possibly originating from combustion processes. The nine other samples...