A5017146197- Seismic Waves and Analysis
- Methane Hydrates and Related Phenomena
- Earthquake Detection and Analysis
- Geophysics and Gravity Measurements
- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Fire effects on ecosystems
- Marine and coastal ecosystems
- Atmospheric and Environmental Gas Dynamics
- Soil and Water Nutrient Dynamics
- Atmospheric chemistry and aerosols
- Peatlands and Wetlands Ecology
- Toxic Organic Pollutants Impact
- Air Quality Monitoring and Forecasting
- Water Quality Monitoring and Analysis
- Isotope Analysis in Ecology
- Odor and Emission Control Technologies
- Hydrology and Watershed Management Studies
- Seismology and Earthquake Studies
- Analytical chemistry methods development
- Microbial Community Ecology and Physiology
- Marine Biology and Ecology Research
- Heavy metals in environment
- Soil erosion and sediment transport
- Fish Ecology and Management Studies
Pacific Northwest National Laboratory
2021-2024
United States Geological Survey
2024
Memorial University of Newfoundland
2020-2023
Florida International University
2017-2021
University of North Carolina Wilmington
2013-2019
About 250 Tg of dissolved organic carbon are annually transported from inland waters to coastal systems making rivers a critical link between terrestrial and ocean pools. During transport through fluvial systems, various biogeochemical processes selectively remove or transform labile material, effectively altering the composition matter (DOM) exported ocean. The river continuum concept (RCC) has been historically used as model predict fate quality along continuum. However, conversion natural...
Spilled oil is highly susceptible to sunlight-induced transformations, both as films on the surface of water and material dissolved or dispersed in column. We utilized ultrahigh-resolution mass spectrometry optical spectroscopy understand shifts photoproduct distributions a function photo-oxygenation. Oxygenation produces compounds that have increased polarity, resulting greater partitioning oil–water interface eventually into aqueous phase. Such was shown be dependent carbon number oxygen...
Rivers export roughly 250 Pg of dissolved organic carbon (DOC) to coastal oceans. DOC exported from rivers can be a reflection watershed dynamics, and changes in land use lead shifts the molecular composition reactivity riverine DOC. About 10% is black (DBC), collection polycondensed aromatic compounds derived incomplete combustion biomass fossil fuels. While DBC are generally coupled, effects on quality not well understood. In this study, samples were collected throughout Altamaha River...
Abstract Warmer and drier climate has contributed to increased occurrence of large, high severity wildfires in the Pacific Northwest, drawing concerns for water quality ecosystem recovery. While nutrient fluxes generally increase post‐fire, composition organic matter (OM) transported streams immediately following a fire is poorly constrained, yet can play an integral role downstream biogeochemistry. Here, we quantified spatiotemporal patterns dissolved OM (DOM) chemistry five burned by...
Abstract. Shifting phosphorus (P) dynamics after wildfires can have cascading impacts from terrestrial to aquatic environments. However, it is unclear if post-fire responses are primarily driven by changes the molecular composition of charred material or transport P-containing compounds. We used laboratory leaching experiments Douglas-fir forest and sagebrush shrubland chars examine how potential mobility P compounds influenced different burn severities. Burning produced a 6.9- 29- fold...
1 INTRODUCTION:Climate change is driving earlier seasonal onset of wildfire, increased fire frequency, and larger fires in many regions globally (Flannigan et al., 2009; Westerling, 2016). Wildfires induce changes ecohydrological processes, including reduced infiltration from soil hydrophobicity (DeBano, 2000), canopy cover that diminishes evapotranspiration interception precipitation (Guo 2023; Wine 2018). The resulting streamflow terrestrial-aquatic connectivity these shifts processes...
Wildfires produce solid residuals that have unique chemical and physical properties compared to unburned materials, which influence their cycling fate in the natural environment. Visual burn severity assessment is used evaluate post-fire alterations landscape field-based studies, yet muffle furnace methods are commonly laboratory studies assess molecular scale along a temperature continuum. Here, we examined leachable organic matter characteristics from chars visually characterized as low...
Abstract Rivers play an important role in the transport of organic carbon from terrestrial to marine environments. A significant portion this material is black (BC), a residue incomplete biomass and fossil fuel combustion. BC mobilized fluvial systems as both particulate (PBC) dissolved (DBC), export coastal environments may have implications for cycling However, while little known regarding potential connectivity between riverine PBC DBC or importance such relationship constraining future...
A large amount of dissolved organic matter (DOM) is transported to the ocean from terrestrial inputs each year (~0.95 Pg C per year) and undergoes a series abiotic biotic reactions, causing significant release CO 2 . Combined, these reactions result in variable DOM characteristics (e.g., nominal oxidation state carbon, double-bond equivalents, chemodiversity) which have demonstrated impacts on biogeochemistry ecosystem function. Despite this importance, however, comparatively few studies...
Abstract Advancing our understanding of dissolved organic matter (DOM) chemistry in aquatic systems necessitates the integration data streams from multiple analytical platforms. Some measurements require pretreatment with solid phase extraction (SPE), while others are performed directly on whole water samples. Evidence has suggested that SPE will be biased against select DOM fractions, leading to concerns over ability establish linkages across platforms variable needs for pretreatment, such...
A new method for the determination of ethanol in aqueous environmental matrixes at nanomolar concentrations is presented and compared to an existing that has been optimized low-level alcohol determinations. The analysis based upon oxidation by enzyme oxidase obtained from yeast Hansenula sp. which quantitatively produces acetaldehyde after reaction 120 min 40 °C pH 9.0. reacts with 2,4-dinitrophenylhydrazine forming a hydrazone separated interfering substances quantified high-performance...
Abstract. Organic matter (OM) composition plays a central role in microbial respiration of dissolved organic and subsequent biogeochemical reactions. Here, direct connection carbon chemistry thermodynamics to reactive transport simulators has been achieved through the newly developed Lambda-PFLOTRAN workflow tool that succinctly incorporates data generated from Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) into reaction networks simulate degradation resulting...
Abstract. Organic matter (OM) composition plays a central role in microbial respiration of dissolved organic and subsequent biogeochemical reactions. Here, direct connection chemistry thermodynamics to reactive transport simulators has been achieved through the newly developed Lambda-PFLOTRAN workflow tool that succinctly incorporates carbon data generated from Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) into reaction networks simulate degradation resulting...
Abstract Application of high‐frequency monitoring dissolved organic carbon (DOC) is difficult in instances where training datasets are challenging to develop (e.g., remote locations) and the relationship between optical features DOC concentration changes due environmental or landscape shifts climate land‐use change). We developed compared three partial least squares (PLS) models using situ water level measurements, conductivity, UV–Vis spectral attenuation predict DOC. Two site‐specific were...