Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

Environmental Sciences

Old Dominion University

Chemistry & Biochemistry Faculty Publications

Articles 1 - 18 of 18

Full-Text Articles in Physical Sciences and Mathematics

Tenvr: Matlab-Based Toolbox For Environmental Research, Aleksandar I. Goranov, Rachel L. Sleighter, Dobromir A. Yordanov, Patrick G. Hatcher Jan 2023

Tenvr: Matlab-Based Toolbox For Environmental Research, Aleksandar I. Goranov, Rachel L. Sleighter, Dobromir A. Yordanov, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

With the advancements in science and technology, datasets become larger and more multivariate, which warrants the need for programming tools for fast data processing and multivariate statistical analysis. Here, the MATLAB-based Toolbox for Environmental Research "TEnvR" (pronounced "ten-ver") is introduced. This novel toolbox includes 44 open-source codes for automated data analysis from a multitude of techniques, such as ultraviolet-visible, fluorescence, and nuclear magnetic resonance spectroscopies, as well as from ultrahigh resolution mass spectrometry. Provided are codes for processing data (e.g., spectral corrections, formula assignment), visualization of figures, calculation of metrics, multivariate statistics, and automated work-up of large datasets. TEnvR allows …

Go to article

The Role Of Microbial Exopolymers In Determining The Fate Of Oil And Chemical Dispersants In The Ocean, Antonietta Quigg, Uta Passow, Wei-Chun Chin, Chen Xu, Shawn Doyle, Laura Bretherton, Manoj Kamalanathan, Alicia K. Williams, Jason B. Sylvan, Zoe V. Finkel, Anthony H. Knap, Kathleen A. Schwehr, Saijin Zhang, Luni Sun, Terry L. Wade, Wassim Obeid, Patrick G. Hatcher, Peter H. Santschi Jan 2016

The Role Of Microbial Exopolymers In Determining The Fate Of Oil And Chemical Dispersants In The Ocean, Antonietta Quigg, Uta Passow, Wei-Chun Chin, Chen Xu, Shawn Doyle, Laura Bretherton, Manoj Kamalanathan, Alicia K. Williams, Jason B. Sylvan, Zoe V. Finkel, Anthony H. Knap, Kathleen A. Schwehr, Saijin Zhang, Luni Sun, Terry L. Wade, Wassim Obeid, Patrick G. Hatcher, Peter H. Santschi

Chemistry & Biochemistry Faculty Publications

The production of extracellular polymeric substances (EPS) by planktonic microbes can influence the fate of oil and chemical dispersants in the ocean through emulsification, degradation, dispersion, aggregation, and/or sedimentation. In turn, microbial community structure and function, including the production and character of EPS, is influenced by the concentration and chemical composition of oil and chemical dispersants. For example, the production of marine oil snow and its sedimentation and flocculent accumulation to the seafloor were observed on an expansive scale after the Deepwater Horizon oil spill in the Northern Gulf of Mexico in 2010, but little is known about the underlying …

Go to article

Upper Tropospheric Water Vapour Variability At High Latitudes- Part 1: Influence Of The Annular Modes, Christopher E. Sioris, Jason Zou, David A. Plummer, Chris D. Boone, C. Thomas Mcelroy, Patrick E. Sheese, Omid Moeini, Peter F. Bernath Jan 2016

Upper Tropospheric Water Vapour Variability At High Latitudes- Part 1: Influence Of The Annular Modes, Christopher E. Sioris, Jason Zou, David A. Plummer, Chris D. Boone, C. Thomas Mcelroy, Patrick E. Sheese, Omid Moeini, Peter F. Bernath

Chemistry & Biochemistry Faculty Publications

Seasonal and monthly zonal medians of water vapour in the upper troposphere and lower stratosphere (UTLS) are calculated for both Atmospheric Chemistry Experiment (ACE) instruments for the northern and southern high-latitude regions (60-90° N and 60-90°S). Chosen for the purpose of observing high-latitude processes, the ACE orbit provides sampling of both regions in 8 of 12 months of the year, with coverage in all seasons. The ACE water vapour sensors, namely MAESTRO (Measurements of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation) and the Fourier Transform Spectrometer (ACE-FTS) are currently the only satellite instruments that can probe from …

Go to article

Molecular Level Characterization Of Diatom-Associated Biopolymers That Bind 234th, ²³³Pa, ²¹°Pb, And 7be In Seawater: A Case Study With Phaeodactylum Tricornutum, Chia-Ying Chuang, Peter H. Santschi, Chen Xu, Yuelu Jiang, Yi-Fang Ho, Patrick G. Hatcher Jan 2015

Molecular Level Characterization Of Diatom-Associated Biopolymers That Bind 234th, ²³³Pa, ²¹°Pb, And 7be In Seawater: A Case Study With Phaeodactylum Tricornutum, Chia-Ying Chuang, Peter H. Santschi, Chen Xu, Yuelu Jiang, Yi-Fang Ho, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

In order to investigate the importance of biogenic silica associated biopolymers on the scavenging of radionuclides, the diatom Phaeodactylum tricornutum was incubated together with the radionuclides Th-234, Pa-233, Pb-210, and Be-7 during their growth phase. Normalized affinity coefficients were determined for the radionuclides bound with different organic compound classes (i.e., proteins, total carbohydrates, uronic acids) in extracellular (nonattached and attached exopolymeric substances), intracellular (ethylene diamine tetraacetic acid and sodium dodecyl sulfate extractable), and frustule embedded biopolymeric fractions (BF). Results indicated that radionuclides were mostly concentrated in frustule BF. Among three measured organic components, Uronic acids showed the strongest affinities to …

Go to article

Mass Loss And Chemical Structures Of Wheat And Maize Straws In Response To Ultravoilet-B Radiation And Soil Contact, Guixiang Zhou, Jiabao Zhang, Jingdong Mao, Congzhi Zhang, Lin Chen, Xiuli Xin, Bingzi Zhao Jan 2015

Mass Loss And Chemical Structures Of Wheat And Maize Straws In Response To Ultravoilet-B Radiation And Soil Contact, Guixiang Zhou, Jiabao Zhang, Jingdong Mao, Congzhi Zhang, Lin Chen, Xiuli Xin, Bingzi Zhao

Chemistry & Biochemistry Faculty Publications

The role of photodegradation, an abiotic process, has been largely overlooked during straw decomposition in mesic ecosystems. We investigated the mass loss and chemical structures of straw decomposition in response to elevated UV-B radiation with or without soil contact over a 12-month litterbag experiment. Wheat and maize straw samples with and without soil contact were exposed to three radiation levels: a no-sunlight control, ambient solar UV-B, and artificially elevated UV-B radiation. A block control with soil contact was not included. Compared with the no-sunlight control, UV-B radiation increased the mass loss by 14-19% and the ambient radiation by 9-16% for …

Go to article

Wavelength And Temperature-Dependent Apparent Quantum Yields For Photochemical Formation Of Hydrogen Peroxide In Seawater, David J. Kieber, Gary W. Miller, Patrick J. Neale, Kenneth Mopper Jan 2014

Wavelength And Temperature-Dependent Apparent Quantum Yields For Photochemical Formation Of Hydrogen Peroxide In Seawater, David J. Kieber, Gary W. Miller, Patrick J. Neale, Kenneth Mopper

Chemistry & Biochemistry Faculty Publications

Wavelength and temperature-dependent apparent quantum yields (AQYs) were determined for the photochemical production of hydrogen peroxide using seawater obtained from coastal and oligotrophic stations in Antarctica, the Pacific Ocean at Station ALOHA, the Gulf of Mexico, and at several sites along the East Coast of the United States. For all samples, AQYs decreased exponentially with increasing wavelength at 25 °C, ranging from 4.6 × 10−4 to 10.4 × 10−4 at 290 nm to 0.17 × 10−4 to 0.97 × 10−4 at 400 nm. AQYs for different seawater samples were remarkably similar irrespective of expected differences in the composition and concentrations …

Go to article

Drift Corrected Trends And Periodic Variations In Mipas Imk/Iaa Ozone Measurements, E. Eckert, T. Von Clarmann, M. Kiefer, G. P. Stiller, S. Lossow, N. Glatthor, D. A. Degenstein, L. Froidevaux, S. Godin-Beekmann, T. Leblanc, S. Mcdermid, M. Pastel, W. Steinbrcht, D.P.J. Swart, K. A. Walker, P. F. Bernath Jan 2014

Drift Corrected Trends And Periodic Variations In Mipas Imk/Iaa Ozone Measurements, E. Eckert, T. Von Clarmann, M. Kiefer, G. P. Stiller, S. Lossow, N. Glatthor, D. A. Degenstein, L. Froidevaux, S. Godin-Beekmann, T. Leblanc, S. Mcdermid, M. Pastel, W. Steinbrcht, D.P.J. Swart, K. A. Walker, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

Drifts, trends and periodic variations were calculated from monthly zonally averaged ozone profiles. The ozone profiles were derived from level-1b data of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) by means of the scientific level-2 processor run by the Karlsruhe Institute of Technology (KIT), Institute for Meteorology and Climate Research (IMK). All trend and drift analyses were performed using a multilinear parametric trend model which includes a linear term, several harmonics with period lengths from 3 to 24 months and the quasi-biennial oscillation (QBO). Drifts at 2-sigma significance level were mainly negative for ozone relative to Aura MLS and …

Go to article

Compositions And Constituents Of Freshwater Dissolved Organic Matter Isolated By Reverse Osmosis, Yulong Zhang, Wen Huang, Jingdong Mao Jan 2014

Compositions And Constituents Of Freshwater Dissolved Organic Matter Isolated By Reverse Osmosis, Yulong Zhang, Wen Huang, Jingdong Mao

Chemistry & Biochemistry Faculty Publications

Dissolved organic matter (DOM) from riverine and lacustrine water was isolated using a reverse osmosis (RO) system. Solid-state 13C nuclear magnetic resonance (13C NMR) was used to quantitatively evaluate the compositions and constituents of DOM, which are compared with previous investigations on marine DOM. Results indicated that concentration factor (CF) was a key metric controlling yield and sorption of DOM on the RO system. The sorption was likely non-selective, based on the 13C NMR and δ13C analyses. Carbohydrates and lipids accounted for 25.0–41.5% and 30.2–46.3% of the identifiable DOM, followed by proteins (18.2–19.8%) and …

Go to article

A Coupled Geochemical And Biogeochemical Approach To Characterize The Bioreactivity Of Dissolved Organic Matter From A Headwater Stream, Rachel L. Sleighter, Rose M. Cory, Louis A. Kaplan, Hussain A.N. Abdulla, Patrick G. Hatcher Jan 2014

A Coupled Geochemical And Biogeochemical Approach To Characterize The Bioreactivity Of Dissolved Organic Matter From A Headwater Stream, Rachel L. Sleighter, Rose M. Cory, Louis A. Kaplan, Hussain A.N. Abdulla, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

The bioreactivity or susceptibility of dissolved organic matter (DOM) to microbial degradation in streams and rivers is of critical importance to global change studies, but a comprehensive understanding of DOM bioreactivity has been elusive due, in part, to the stunningly diverse assemblages of organic molecules within DOM. We approach this problem by employing a range of techniques to characterize DOM as it flows through biofilm reactors: dissolved organic carbon (DOC) concentrations, excitation emission matrix spectroscopy (EEMs), and ultrahigh resolution mass spectrometry. The EEMs and mass spectral data were analyzed using a combination of multivariate statistical approaches. We found that 45% …

Go to article

Estimating Hydroxyl Radical Photochemical Formation Rates In Natural Waters During Long-Term Laboratory Irradiation Experiments, Luni Sun, Hongmei Chen, Hussain A. Abdulla, Kenneth Mopper Jan 2014

Estimating Hydroxyl Radical Photochemical Formation Rates In Natural Waters During Long-Term Laboratory Irradiation Experiments, Luni Sun, Hongmei Chen, Hussain A. Abdulla, Kenneth Mopper

Chemistry & Biochemistry Faculty Publications

In this study it was observed that, during long-term irradiations (>1 day) of natural waters, the methods for measuring hydroxyl radical (˙OH) formation rates based upon sequentially determined cumulative concentrations of photoproducts from probes significantly underestimate actual ˙OH formation rates. Performing a correction using the photodegradation rates of the probe products improves the ˙OH estimation for short term irradiations (<1 day), but not long term irradiations. Only the ‘instantaneous’ formation rates, which were obtained by adding probes to aliquots at each time point and irradiating these sub-samples for a short time (≤2 h), were found appropriate for accurately estimating ˙OH photochemical formation rates during long-term laboratory irradiation experiments. Our results also showed that in iron- and dissolved organic matter (DOM)-rich water samples, ˙OH appears to be mainly produced from the Fenton reaction initially, but subsequently from other sources possibly from DOM photoreactions. Pathways of ˙OH formation in long-term irradiations in relation to H2O2 and iron concentrations are discussed.

Go to article

Harmonized Dataset Of Ozone Profiles From Satellite Limb And Occultation Measurements, V. F. Sofieva, N. Rahpoe, J. Tamminen, E. Kyrölä, N. Kalakoski, M. Weber, A. Rozanov, C. Von Savigny, A Laeng, T. Von Clarmann, P. Bernath, R. J. Hargreaves Jan 2013

Harmonized Dataset Of Ozone Profiles From Satellite Limb And Occultation Measurements, V. F. Sofieva, N. Rahpoe, J. Tamminen, E. Kyrölä, N. Kalakoski, M. Weber, A. Rozanov, C. Von Savigny, A Laeng, T. Von Clarmann, P. Bernath, R. J. Hargreaves

Chemistry & Biochemistry Faculty Publications

In this paper, we present a HARMonized dataset of OZone profiles (HARMOZ) based on limb and occultation measurements from Envisat (GOMOS, MIPAS and SCIAMACHY), Odin (OSIRIS, SMR) and SCISAT (ACE-FTS) satellite instruments. These measurements provide high-vertical-resolution ozone profiles covering the altitude range from the upper troposphere up to the mesosphere in years 2001-2012. HARMOZ has been created in the framework of the European Space Agency Climate Change Initiative project. The harmonized dataset consists of original retrieved ozone profiles from each instrument, which are screened for invalid data by the instrument teams. While the original ozone profiles are presented in different …

Go to article

Role Of Extractable And Residual Organic Matter Fractions On Sorption Of Phenanthrene In Sediments, Yulong Zhang, Yong Ran, Jingdong Mao Jan 2013

Role Of Extractable And Residual Organic Matter Fractions On Sorption Of Phenanthrene In Sediments, Yulong Zhang, Yong Ran, Jingdong Mao

Chemistry & Biochemistry Faculty Publications

Two sediments were demineralized and sequentially fractionated into extracted fractions [free lipid (FL), bound lipid (BL) and lignin (LG)] and residual fractions [free lipid free (FLF), bound lipid free (BLF) and lignin free (LGF)]. The sorption isotherms of phenanthrene (Phen) were examined to evaluate the importance of various fractions on sorption. A lignin extraction procedure was for the first time applied to separate the lignin or degraded lignin fraction from sediment organic matter (SOM). The extracted LG was similar to model lignin in terms of elemental ratios and sorption behavior. FL and LG fractions were quite important, as their contents …

Go to article

Effects Of Root-Zone Temperature And N, P, And K Supplies On Nutrient Uptake Of Cucumber (Cucumis Sativus L.) Seedlings In Hydroponics, Qiuyan Yan, Zengqiang Duan, Jingdong Mao, Xun Li, Fei Dong Jan 2012

Effects Of Root-Zone Temperature And N, P, And K Supplies On Nutrient Uptake Of Cucumber (Cucumis Sativus L.) Seedlings In Hydroponics, Qiuyan Yan, Zengqiang Duan, Jingdong Mao, Xun Li, Fei Dong

Chemistry & Biochemistry Faculty Publications

The nutrient uptake and allocation of cucumber (Cucumis sativus L.) seedlings at different root-zone temperatures (RZT) and different concentrations of nitrogen (N), phosphorus (P), and potassium (K) nutrients were examined. Plants were grown in a nutrient solution for 30 d at two root-zone temperatures (a diurnally fluctuating ambient 10°C-RZT and a constant 20° C-RZT) with the aerial parts of the plants maintained at ambient temperature (10°C -30°C). Based on a Hoagland nutrient solution, seven N, P, and K nutrient concentrations were supplied to the plants at each RZT. Results showed that total plant and shoot dry weights under …

Go to article

Fossil And Contemporary Aerosol Particulate Organic Carbon In The Eastern United States: Implications For Deposition And Inputs To Watersheds, Andrew S. Wozniak, James E. Bauer, Rebecca M. Dickhut Jan 2011

Fossil And Contemporary Aerosol Particulate Organic Carbon In The Eastern United States: Implications For Deposition And Inputs To Watersheds, Andrew S. Wozniak, James E. Bauer, Rebecca M. Dickhut

Chemistry & Biochemistry Faculty Publications

Atmospheric particulate matter samples were collected from mid-Atlantic and northeastern U. S. (Virginia and New York, respectively) sites to assess the fossil versus contemporary sources contributing to aerosol organic carbon (OC) and the implications for its deposition to watersheds. Mean particulate matter total OC (TOC) deposition rates (wet + dry deposition) were calculated to be 1.6 and 2.4 mg C m-2 d-1 for the Virginia and New York sites, respectively. Wet deposition of particulate TOC was determined to be the dominant depositional mode, accounting for >65% (Virginia) and >80% (New York) of total aerosol TOC deposition. Isotopic mass …

Go to article

Temporal Controls On Dissolved Organic Matter And Lignin Biogeochemistry In A Pristine Tropical River, Democratic Republic Of Congo, Robert G. M. Spencer, Peter J. Hernes, Rosmarie Ruf, Andy Baker, Rachael Y. Dyda, Aron Stubbins, Johan Six Jan 2010

Temporal Controls On Dissolved Organic Matter And Lignin Biogeochemistry In A Pristine Tropical River, Democratic Republic Of Congo, Robert G. M. Spencer, Peter J. Hernes, Rosmarie Ruf, Andy Baker, Rachael Y. Dyda, Aron Stubbins, Johan Six

Chemistry & Biochemistry Faculty Publications

Dissolved organic carbon (DOC), lignin biomarkers, and the optical properties of dissolved organic matter (DOM) were measured in the Epulu River (northeast Democratic Republic of Congo) with the aim of investigating temporal controls on the quantity and chemical composition of DOM in a tropical rainforest river. Three different periods defined by stages of the hydrologic regime of the region, (1) post dry flushing period, (2) intermediary period, and (3) start of the dry period/post flush, were sampled. Temporal variability in DOM quantity and quality was observed with highest DOC, lignin concentration (Σ8) and carbon‐normalized (Λ8) values …

Go to article

Effluent Organic Nitrogen (Eon): Bioavailability And Photochemical And Salinity-Mediated Release, Deborah A. Bronk, Quinn N. Roberts, Marta P. Sanderson, Elizabeth A. Canuel, Patrick G. Hatcher, Rajaa Mesfioui, Katherine C. Filippino, Margaret R. Mulholland, Nancy G. Love Jan 2010

Effluent Organic Nitrogen (Eon): Bioavailability And Photochemical And Salinity-Mediated Release, Deborah A. Bronk, Quinn N. Roberts, Marta P. Sanderson, Elizabeth A. Canuel, Patrick G. Hatcher, Rajaa Mesfioui, Katherine C. Filippino, Margaret R. Mulholland, Nancy G. Love

Chemistry & Biochemistry Faculty Publications

The goal of this study was to investigate three potential ways that the soluble organic nitrogen (N) fraction of wastewater treatment plant (WWTP) effluents, termed effluent organic N (EON), could contribute to coastal eutrophication - direct biological removal, photochemical release of labile compounds, and salinity-mediated release of ammonium (NH4+). Effluents from two WWTPs were used in the experiments. For the bioassays, EON was added to water from four salinities (∼0 to 30) collected from the James River (VA) in August 2008, and then concentrations of N and phosphorus compounds were measured periodically over 48 h. Bioassay results, based …

Go to article

Photochemical Degradation Of Dissolved Organic Matter And Dissolved Lignin Phenols From The Congo River, Robert G. M. Spencer, Aron Stubbins, Peter J. Hernes, Kenneth Mopper, Anthony K. Aufdenkampe, Rachael Y. Dyda, Vincent L. Mwamba, Arthur M. Mangangu, Jose N. Wabakanghanzi, Johan Six Jan 2009

Photochemical Degradation Of Dissolved Organic Matter And Dissolved Lignin Phenols From The Congo River, Robert G. M. Spencer, Aron Stubbins, Peter J. Hernes, Kenneth Mopper, Anthony K. Aufdenkampe, Rachael Y. Dyda, Vincent L. Mwamba, Arthur M. Mangangu, Jose N. Wabakanghanzi, Johan Six

Chemistry & Biochemistry Faculty Publications

Photochemical degradation of Congo River dissolved organic matter (DOM) was investigated to examine the fate of terrigenous DOM derived from tropical ecosystems. Tropical riverine DOM receives greater exposure to solar radiation, particularly in large river plumes discharging directly into the open ocean. Initial Congo River DOM exhibited dissolved organic carbon (DOC) concentration and compositional characteristics typical of organic rich blackwater systems. During a 57 day irradiation experiment, Congo River DOM was shown to be highly photoreactive with a decrease in DOC, chromophoric DOM (CDOM), lignin phenol concentrations (Σ8) and carbon-normalized yields (Λ8), equivalent to losses of ~45, 85–95, >95 and …

Go to article

Determination Of Photochemically Produced Carbon Dioxide In Seawater, Emily M. White, David J. Kieber, Kenneth Mopper Jan 2008

Determination Of Photochemically Produced Carbon Dioxide In Seawater, Emily M. White, David J. Kieber, Kenneth Mopper

Chemistry & Biochemistry Faculty Publications

An analytical system was developed to determine photochemically produced carbon dioxide in marine waters. Our system was designed to measure low levels of carbon dioxide by maintaining a closed system to prevent atmospheric contamination during sample preparation, irradiation, and analysis. To detect low levels of photoproduced carbon dioxide in seawater, background dissolved inorganic carbon (DIC) was removed before irradiation. To strip out DIC, samples were acidified to pH 3.0 (converting DIC to carbon dioxide) and bubbled with low carbon dioxide air. The pH was then readjusted back to the original value, and the resulting low-DIC seawater samples were transferred pneumatically …

Go to article