A5035939898- Marine and coastal ecosystems
- Plant and animal studies
- Water Quality Monitoring and Analysis
- Ecology and Vegetation Dynamics Studies
- Atmospheric chemistry and aerosols
- Forest Insect Ecology and Management
- Isotope Analysis in Ecology
- Insect-Plant Interactions and Control
- Marine Biology and Ecology Research
- Analytical Chemistry and Chromatography
- Atmospheric and Environmental Gas Dynamics
- Microbial Community Ecology and Physiology
- Ocean Acidification Effects and Responses
- Air Quality Monitoring and Forecasting
- Advanced Chemical Sensor Technologies
- Atmospheric Ozone and Climate
- Fire effects on ecosystems
- Plant Parasitism and Resistance
- Analytical chemistry methods development
- Marine and environmental studies
- Mass Spectrometry Techniques and Applications
- Advanced oxidation water treatment
- Coastal wetland ecosystem dynamics
- Genetic diversity and population structure
- Aquatic Ecosystems and Phytoplankton Dynamics
Old Dominion University
2007-2024
University of Louisiana at Lafayette
2008-2021
Dominion University College
2014
Washington State University
1992-2011
Nanjing University
2010
United States Geological Survey
2003-2008
Plymouth Marine Laboratory
2008
Newcastle University
2008
University of Kansas
2003
Cornell University
2003
Specific UV absorbance (SUVA) is defined as the of a water sample at given wavelength normalized for dissolved organic carbon (DOC) concentration. Our data indicate that SUVA, determined 254 nm, strongly correlated with percent aromaticity by 13C NMR 13 matter isolates obtained from variety aquatic environments. therefore, shown to be useful parameter estimating aromatic content in systems. Experiments involving reactivity DOC chlorine and tetra- methylammonium hydroxide (TMAH), however,...
A new approach for parameterizing dissolved organic matter (DOM) ultraviolet‐visible absorption spectra is presented. Two distinct spectral slope regions (275‐295 nm and 350‐400 nm) within log‐transformed were used to compare DOM from contrasting water types, ranging wetlands (Great Dismal Swamp Suwannee River) photobleached oceanic (Atlantic Ocean). On the basis of size‐fractionation studies (ultrafiltration gel filtration chromatography), 275‐295‐nm region ratio these slopes ( S R ; :...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHigh performance liquid chromatographic determination of subpicomole amounts amino acids by precolumn fluorescence derivatization with o-phthaldialdehydePeter. Lindroth and Kenneth. MopperCite this: Anal. Chem. 1979, 51, 11, 1667–1674Publication Date (Print):September 1, 1979Publication History Published online1 May 2002Published inissue 1 September...
Congo River water was filtered and then irradiated for 57 d in a solar simulator, resulting extensive photodegradation of dissolved organic matter (DOM). Whole‐water (i.e., unfractionated) DOM analyzed pre‐ post‐irradiation using ultrahigh resolution Fourier transform ion cyclotron mass spectrometry (FT‐ICR MS), revealing the following three pools classified based upon their photoreactivity: (1) photo‐resistant, (2) photo‐labile, (3) photo‐produced. Photo‐resistant heterogeneous, with most...
Photochemical production rates and steady-state concentrations of hydroxyl radicals (⋅OH) were measured in sunlight-irradiated seawater. Values ranged from 110 nanomolar per hour 12 × 10 -18 molar coastal surface water to 1.1 open ocean water. The wavelengths responsible for this are the ultraviolet B region (280 320 nanometers) solar spectrum. Dissolved organic matter (DOM) appears be main source ⋅OH over most oceans, but upwelling areas nitrite nitrate photolysis may also important. DOM...
Low‐molecular‐weight (LMW) carbonyl compounds, e.g. formaldehyde, acetaldehyde, and the α ‐keto acid glyoxylate, were produced in a wide variety of natural waters upon irradiation with sunlight. Production rates linearly related ( r 2 > 0.98) to initial absorbance at 300 nm fluorescence (360/460 nm) all tested. Photochemical production was also loss (photobleaching) during irradiation, irrespective time prior photobleaching history sample. These results attributed absorption light by...
Photochemical degradation of Congo River dissolved organic matter (DOM) was investigated to examine the fate terrigenous DOM derived from tropical ecosystems. Tropical riverine receives greater exposure solar radiation, particularly in large river plumes discharging directly into open ocean. Initial exhibited carbon (DOC) concentration and compositional characteristics typical rich blackwater systems. During a 57 day irradiation experiment, shown be highly photoreactive with decrease DOC,...
A variety of short-lived, reactive chemical species (i.e. free radicals and excited state species) are known to be photochemically produced in natural waters. Some these transients may strongly affect biological processes, they have been implicated the degradation organic pollutants compounds aqueous environments. Previous studies demonstrated that highly hydroxyl radical (OH) is formed seawater. However, quantitative importance this key sea has not previously studied because past analytical...
Experiments were performed to examine the role of surface‐active polysaccharides in formation transparent exopolymer particles (TEP) by bubble adsorption seawater. Filtered (1.0 µm, 0.45 µm) and ultrafiltered (0.1 100 kDa, 10 kDa) seawater samples bubbled a glass foam tower. The neutral sugar composition, concentration TEP, carbohydrates generated determined. Three different surface (Monterey Bay, California; Shannon Point, Anacortes, Washington; East Sound, Orcas Island, Washington) used...
A precolumn fluorimetric labeling method was tested for shipboard HPLC analysis of dissolved free amino acids (DFAA) in natural waters. No sample preparation is required and all naturally occurring plus ammonium are sufficiently separated within 30 min. Striking diel trends were observed to a depth at least 60 m, with maximal DFAA concentrations (200–400 nM) the late evening minimal (30–40 early day. Concurrent concentration maxima elevated relative abundances basic (especially ornithine...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTApparent partition coefficients of 15 carbonyl compounds between air and seawater freshwater; implications for air-sea exchangeXianliang Zhou Kenneth MopperCite this: Environ. Sci. Technol. 1990, 24, 12, 1864–1869Publication Date (Print):December 1, 1990Publication History Published online1 May 2002Published inissue 1 December 1990https://pubs.acs.org/doi/10.1021/es00082a013https://doi.org/10.1021/es00082a013research-articleACS PublicationsRequest...
Pinyon pine, Pinus edulis (Engelm.), in Northern Arizona is exposed to recurring high levels of herbivory by the moth Dioryctria albovitella (Hust.). During a 3-year period, infested trees experienced on average 30 percent reduction annual shoot production. This affects tree architecture, growth rate, reproductive output, and sexual expression. Less produce 47 more trunk wood, 43 branch are monoecious. Architectural changes can result infunctionally male plants due complete loss normal...