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Articles 31 - 60 of 69
Full-Text Articles in Environmental Chemistry
Leaf Traits Can Be Used To Predict Rates Of Litter Decomposition, Marc Rosenfield, Jennifer L. Funk, Jason K. Keller, Catrina Clausen, Kimberlee Cyphers
Leaf Traits Can Be Used To Predict Rates Of Litter Decomposition, Marc Rosenfield, Jennifer L. Funk, Jason K. Keller, Catrina Clausen, Kimberlee Cyphers
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Strong relationships exist between litter chemistry traits and rates of litter decomposition. However, leaf traits are more commonly found in online trait databases than litter traits and fewer studies have examined how well leaf traits predict litter decomposition rates. Furthermore, while bulk leaf nitrogen (N) content is known to regulate litter decomposition, few studies have explored the importance of N biochemistry fractions, such as protein and amino acid concentration. Here, we decomposed green leaves and naturally senesced leaf litter of nine species representing a wide range of leaf functional traits. We evaluated the ability of traits associated with leaf and …
Massive Peatland Carbon Banks Vulnerable To Rising Temperatures, A. M. Hopple, R. M. Wilson, M. Kolton, Cassandra A. Zalman, J. P. Chanton, J. Kostka, P. J. Hanson, Jason K. Keller, S. D. Bridgham
Massive Peatland Carbon Banks Vulnerable To Rising Temperatures, A. M. Hopple, R. M. Wilson, M. Kolton, Cassandra A. Zalman, J. P. Chanton, J. Kostka, P. J. Hanson, Jason K. Keller, S. D. Bridgham
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Peatlands contain one-third of the world’s soil carbon (C). If destabilized, decomposition of this vast C bank could accelerate climate warming; however, the likelihood of this outcome remains unknown. Here, we examine peatland C stability through five years of whole-ecosystem warming and two years of elevated atmospheric carbon dioxide concentrations (eCO2). Warming exponentially increased methane (CH4) emissions and enhanced CH4 production rates throughout the entire soil profile; although surface CH4 production rates remain much greater than those at depth. Additionally, older deeper C sources played a larger role in decomposition following prolonged warming. Most …
Synergistic Use Of Remote Sensing And Modeling For Estimating Net Primary Productivity In The Red Sea With Vgpm, Eppley-Vgpm, And Cbpm Models Intercomparison, Wenzhao Li, Surya Prakash Tiwari, Hesham El-Askary, Mohamed Ali Qurban, Vassilis Amiridis, K. P. Manikandan, Michael J. Garay, Olga V. Kalashnikova, Thomas C. Piechota, Daniele C. Struppa
Synergistic Use Of Remote Sensing And Modeling For Estimating Net Primary Productivity In The Red Sea With Vgpm, Eppley-Vgpm, And Cbpm Models Intercomparison, Wenzhao Li, Surya Prakash Tiwari, Hesham El-Askary, Mohamed Ali Qurban, Vassilis Amiridis, K. P. Manikandan, Michael J. Garay, Olga V. Kalashnikova, Thomas C. Piechota, Daniele C. Struppa
Mathematics, Physics, and Computer Science Faculty Articles and Research
Primary productivity (PP) has been recently investigated using remote sensing-based models over quite limited geographical areas of the Red Sea. This work sheds light on how phytoplankton and primary production would react to the effects of global warming in the extreme environment of the Red Sea and, hence, illuminates how similar regions may behave in the context of climate variability. study focuses on using satellite observations to conduct an intercomparison of three net primary production (NPP) models--the vertically generalized production model (VGPM), the Eppley-VGPM, and the carbon-based production model (CbPM)--produced over the Red Sea domain for the 1998-2018 time period. …
Methanethiol, Dimethyl Sulfide And Acetone Over Biologically Productive Waters In The Southwest Pacific Ocean, Sarah J. Lawson, Cliff S. Law, Mike J. Harvey, Thomas G. Bell, Carolyn F. Walker, Warren J. De Bruyn, Eric S. Saltzman
Methanethiol, Dimethyl Sulfide And Acetone Over Biologically Productive Waters In The Southwest Pacific Ocean, Sarah J. Lawson, Cliff S. Law, Mike J. Harvey, Thomas G. Bell, Carolyn F. Walker, Warren J. De Bruyn, Eric S. Saltzman
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Atmospheric methanethiol (MeSHa), dimethyl sulfide (DMSa) and acetone (acetonea) were measured over biologically productive frontal waters in the remote southwest Pacific Ocean in summertime 2012 during the Surface Ocean Aerosol Production (SOAP) voyage. MeSHa mixing ratios varied from below the detection limit (< 10 ppt) up to 65 ppt and were 3 %–36 % of parallel DMSa mixing ratios. MeSHa and DMSa were correlated over the voyage (R2=0.3, slope = 0.07) with a stronger correlation over a coccolithophore-dominated phytoplankton bloom (R2=0.5, slope 0.13). The diurnal cycle for MeSHa shows similar behaviour to DMSa with mixing ratios …
Air/Sea Transfer Of Highly Soluble Gases Over Coastal Waters, J. G. Porter, Warren J. De Bruyn, S. D. Miller, E. S. Saltzman
Air/Sea Transfer Of Highly Soluble Gases Over Coastal Waters, J. G. Porter, Warren J. De Bruyn, S. D. Miller, E. S. Saltzman
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
The deposition of soluble trace gases to the sea surface is not well studied due to a lack of flux measurements over the ocean. Here we report simultaneous air/sea eddy covariance flux measurements of water vapor, sulfur dioxide (SO2), and momentum from a coastal North Atlantic pier. Gas transfer velocities were on average about 20% lower for SO2 than for H2O. This difference is attributed to the difference in molecular diffusivity between the two molecules (D SO 2/D H 2O = 0.5), in reasonable agreement with bulk parameterizations in air/sea gas …
Anoxic Conditions Maintained High Phosphorus Sorption In Humid Tropical Forest Soils, Yang Lin, Avner Gross, Christine S. O'Connell, Whendee L. Silver
Anoxic Conditions Maintained High Phosphorus Sorption In Humid Tropical Forest Soils, Yang Lin, Avner Gross, Christine S. O'Connell, Whendee L. Silver
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
The strong phosphorus (P) sorption capacity of iron (Fe) and aluminum (Al) minerals in highly weathered, acidic soils of humid tropical forests is generally assumed to be an important driver of P limitation to plants and microbial activity in these ecosystems. Humid tropical forest soils often experience fluctuating redox conditions that reduce Fe and raise pH. It is commonly thought that Fe reduction generally decreases the capacity and strength of P sorption. Here we examined the effects of 14 d oxic and anoxic incubations on soil P sorption dynamics in humid tropical forest soils from Puerto Rico. Contrary to the …
Global Sinusoidal Seasonality In Precipitation Isotopes, Scott T. Allen, Scott Jasechko, Wouter R. Berghuijs, Jeffrey M. Welker, Gregory R. Goldsmith, James W. Kirchner
Global Sinusoidal Seasonality In Precipitation Isotopes, Scott T. Allen, Scott Jasechko, Wouter R. Berghuijs, Jeffrey M. Welker, Gregory R. Goldsmith, James W. Kirchner
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Quantifying seasonal variations in precipitation δ2H and δ18O is important for many stable isotope applications, including inferring plant water sources and streamflow ages. Our objective is to develop a data product that concisely quantifies the seasonality of stable isotope ratios in precipitation. We fit sine curves defined by amplitude, phase, and offset parameters to quantify annual precipitation isotope cycles at 653 meteorological stations on all seven continents. At most of these stations, including in tropical and subtropical regions, sine curves can represent the seasonal cycles in precipitation isotopes. Additionally, the amplitude, phase, and offset parameters of …
Purification And Characterization Of A Nonspecific Lipid Transfer Protein 1 (Nsltp1) From Ajwain (Trachyspermum Ammi) Seeds, Meshal Nazeer, Humera Waheed, Maria Saeed, Saman Yousuf Ali, M. Iqbal Choudhary, Zaheer Ul-Haq, Aftab Ahmed
Purification And Characterization Of A Nonspecific Lipid Transfer Protein 1 (Nsltp1) From Ajwain (Trachyspermum Ammi) Seeds, Meshal Nazeer, Humera Waheed, Maria Saeed, Saman Yousuf Ali, M. Iqbal Choudhary, Zaheer Ul-Haq, Aftab Ahmed
Pharmacy Faculty Articles and Research
Ajwain (Trachyspermum ammi) belongs to the family Umbelliferae, is commonly used in traditional, and folk medicine due to its carminative, stimulant, antiseptic, diuretic, antihypertensive, and hepatoprotective activities. Non-specific lipid transfer proteins (nsLTPs) reported from various plants are known to be involved in transferring lipids between membranes and in plants defense response. Here, we describe the complete primary structure of a monomeric non-specific lipid transfer protein 1 (nsLTP1), with molecular weight of 9.66 kDa, from ajwain seeds. The nsLTP1 has been purified by combination of chromatographic techniques, and further characterized by mass spectrometry, and Edman degradation. The ajwain nsLTP1 …
Seasonal Origins Of Soil Water Used By Trees, Scott T. Allen, James W. Kirchner, Sabine Braun, Rolf T. W. Siegwolf, Gregory R. Goldsmith
Seasonal Origins Of Soil Water Used By Trees, Scott T. Allen, James W. Kirchner, Sabine Braun, Rolf T. W. Siegwolf, Gregory R. Goldsmith
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Rain recharges soil water storages and either percolates downward into aquifers and streams or is returned to the atmosphere through evapotranspiration. Although it is commonly assumed that summer rainfall recharges plant-available water during the growing season, the seasonal origins of water used by plants have not been systematically explored. We characterize the seasonal origins of waters in soils and trees by comparing their midsummer isotopic signatures (δ2H) to seasonal isotopic cycles in precipitation, using a new seasonal origin index. Across 182 Swiss forest sites, xylem water isotopic signatures show that summer rain was not the predominant water source …
Spatial Variation In Throughfall, Soil, And Plant Water Isotopes In A Temperate Forest, Gregory R. Goldsmith, Scott T. Allen, Sabine Braun, Nadine Engbersen, Clara Romero González-Quijano, James W. Kirchner, Rolf T. W. Siegwolf
Spatial Variation In Throughfall, Soil, And Plant Water Isotopes In A Temperate Forest, Gregory R. Goldsmith, Scott T. Allen, Sabine Braun, Nadine Engbersen, Clara Romero González-Quijano, James W. Kirchner, Rolf T. W. Siegwolf
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Studies of stable isotopes of water in the environment have been fundamental to advancing our understanding of how water moves through the soil‐plant‐atmosphere continuum; however, much of this research focuses on how water isotopes vary in time, rather than in space. We examined the spatial variation in the δ18O and δ2H of throughfall and bulk soil water, as well as branch xylem and bulk leaf water of Picea abies (Norway Spruce) and Fagus sylvatica (Beech), in a 1 ha forest plot in the northern Alps of Switzerland. Means and ranges of water isotope ratios varied considerably …
Hot Spots And Hot Moments Of Soil Moisture Explain Fluctuations In Iron And Carbon Cycling In A Humid Tropical Forest Soil, Diego Barcellos, Christine S. O'Connell, Whendee L. Silver, Christof Meile, Aaron Thompson
Hot Spots And Hot Moments Of Soil Moisture Explain Fluctuations In Iron And Carbon Cycling In A Humid Tropical Forest Soil, Diego Barcellos, Christine S. O'Connell, Whendee L. Silver, Christof Meile, Aaron Thompson
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Soils from humid forests undergo spatial and temporal variations in moisture and oxygen (O2) in response to rainfall, and induce changes in iron (Fe) and carbon (C) biogeochemistry. We hypothesized that high rainfall periods stimulate Fe and C cycling, with the greatest effects in areas of high soil moisture. To test this, we measured Fe and C cycling across three catenas at valley, slope, and ridge positions every two days for a two-month period in a rainforest in Puerto Rico. Over 12 days without rain, soil moisture, FeII, rapidly reducible Fe oxides (FeIIIRR), …
Eddy Flux Measurements Of Sulfur Dioxide Deposition To The Sea Surface, Jack G. Porter, Warren J. De Bruyn, Eric S. Saltzman
Eddy Flux Measurements Of Sulfur Dioxide Deposition To The Sea Surface, Jack G. Porter, Warren J. De Bruyn, Eric S. Saltzman
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Deposition to the sea surface is a major atmospheric loss pathway for many important trace gases, such as sulfur dioxide (SO2). The air–sea transfer of SO2 is controlled entirely on the atmospheric side of the air–sea interface due to high effective solubility and other physical– chemical properties. There have been few direct field measurements of such fluxes due to the challenges associated with making fast-response measurements of highly soluble trace gases at very low ambient levels. In this study, we report direct eddy covariance air–sea flux measurements of SO2, sensible heat, water vapor, and momentum. The measurements were made over …
Deep Soils Modify Environmental Consequences Of Increased Nitrogen Fertilizer Use In Intensifying Amazon Agriculture, Kathijo Jankowski, Christopher Neill, Eric A. Davidson, Marcia Macedo, Ciniro Costa Jr., Gillian L. Galford, Leonardo Maracahipes Santos, Paul Lefebvre, Darlisson Nunes, Carlos E. P. Cerri, Richard Mchorney, Christine S. O'Connell, Michael T. Coe
Deep Soils Modify Environmental Consequences Of Increased Nitrogen Fertilizer Use In Intensifying Amazon Agriculture, Kathijo Jankowski, Christopher Neill, Eric A. Davidson, Marcia Macedo, Ciniro Costa Jr., Gillian L. Galford, Leonardo Maracahipes Santos, Paul Lefebvre, Darlisson Nunes, Carlos E. P. Cerri, Richard Mchorney, Christine S. O'Connell, Michael T. Coe
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Agricultural intensification offers potential to grow more food while reducing the conversion of native ecosystems to croplands. However, intensification also risks environmental degradation through emissions of the greenhouse gas nitrous oxide (N2O) and nitrate leaching to ground and surface waters. Intensively-managed croplands and nitrogen (N) fertilizer use are expanding rapidly in tropical regions. We quantified fertilizer responses of maize yield, N2O emissions, and N leaching in an Amazon soybean-maize double-cropping system on deep, highly-weathered soils in Mato Grosso, Brazil. Application of N fertilizer above 80 kg N ha−1 yr−1 increased maize yield and N …
Predicting Spatial Patterns In Precipitation Isotope (Δ2h And Δ18o) Seasonality Using Sinusoidal Isoscapes, Scott T. Allen, James W. Kirchner, Gregory R. Goldsmith
Predicting Spatial Patterns In Precipitation Isotope (Δ2h And Δ18o) Seasonality Using Sinusoidal Isoscapes, Scott T. Allen, James W. Kirchner, Gregory R. Goldsmith
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Understanding how precipitation isotopes vary spatially and temporally is important for tracer applications. We tested how well month‐to‐month variations in precipitation δ18O and δ2H were captured by sinusoidal cycles, and how well spatial variations in these seasonal cycles could be predicted, across Switzerland. Sine functions representing seasonal cycles in precipitation isotopes explained between 47% and 94% of the variance in monthly δ18O and δ2H values at each monitoring site. A significant sinusoidal cycle was also observed in line‐conditioned excess. We interpolated the amplitudes, phases, and offsets of these sine functions across the landscape, using multiple linear …
Automating Data Analysis For Two-Dimensional Gas Chromatography/Time-Of-Flight Mass Spectrometry Non-Targeted Analysis Of Comparative Samples, Ivan A. Titaley, O. Maduka Ogba, Leah Chibwe, Eunha Hoh, Paul H.-Y. Cheong, Staci L. Massey Simonich
Automating Data Analysis For Two-Dimensional Gas Chromatography/Time-Of-Flight Mass Spectrometry Non-Targeted Analysis Of Comparative Samples, Ivan A. Titaley, O. Maduka Ogba, Leah Chibwe, Eunha Hoh, Paul H.-Y. Cheong, Staci L. Massey Simonich
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Non-targeted analysis of environmental samples, using comprehensive two‐dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC × GC/ToF-MS), poses significant data analysis challenges due to the large number of possible analytes. Non-targeted data analysis of complex mixtures is prone to human bias and is laborious, particularly for comparative environmental samples such as contaminated soil pre- and post-bioremediation. To address this research bottleneck, we developed OCTpy, a Python™ script that acts as a data reduction filter to automate GC × GC/ToF-MS data analysis from LECO® ChromaTOF® software and facilitates selection of analytes of interest based on peak area …
No Evidence For Trace Metal Limitation On Anaerobic Carbon Mineralization In Three Peatland Soils, Jason K. Keller, Jillian Wade
No Evidence For Trace Metal Limitation On Anaerobic Carbon Mineralization In Three Peatland Soils, Jason K. Keller, Jillian Wade
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Peatlands store roughly one-third of the terrestrial soil carbon and release the potent greenhouse gas methane (CH4) to the atmosphere, making these wetlands among the most important ecosystems in the global carbon cycle. Despite their importance, the controls of anaerobic decomposition of organic matter to carbon dioxide (CO2) and CH4 within peatlands are not well understood. It is known, however, that the enzymes responsible for CH4 production require cobalt, iron and nickel, and there is a growing appreciation for the potential role of trace metal limitation in anaerobic decomposition. To explore the possibility of …
Estimation Of Bubble-Mediated Air–Sea Gas Exchange From Concurrent Dms And Co2 Transfer Velocities At Intermediate–High Wind Speeds, Thomas G. Bell, Sebastian Landwehr, Scott D. Miller, Warren J. De Bruyn, Adrian H. Callaghan, Brian Scanlon, Brian Ward, Mingxi Yang, Eric S. Saltzman
Estimation Of Bubble-Mediated Air–Sea Gas Exchange From Concurrent Dms And Co2 Transfer Velocities At Intermediate–High Wind Speeds, Thomas G. Bell, Sebastian Landwehr, Scott D. Miller, Warren J. De Bruyn, Adrian H. Callaghan, Brian Scanlon, Brian Ward, Mingxi Yang, Eric S. Saltzman
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Simultaneous air–sea fluxes and concentration differences of dimethylsulfide (DMS) and carbon dioxide (CO2/ were measured during a summertime North Atlantic cruise in 2011. This data set reveals significant differences between the gas transfer velocities of these two gases (1kw/ over a range of wind speeds up to 21ms1. These differences occur at and above the approximate wind speed threshold when waves begin breaking. Whitecap fraction (a proxy for bubbles) was also measured and has a positive relationship with 1kw, consistent with enhanced bubble-mediated transfer of the less soluble CO2 relative to that of the more soluble DMS. However, the correlation …
Hydrogenation Of Organic Matter As A Terminal Electron Sink Sustains High Co2:Ch4 Production Ratios During Anaerobic Decomposition, Rachel M. Wilson, Malak M. Tfaily, Virginia I. Rich, Jason K. Keller, Scott D. Bridgham, Cassandra Medvedeff Zalman, Laura Meredith, Paul J. Hanson, Mark Hines, Laurel Pfeifer-Meister, Scott R. Saleska, Patrick Crill, William T. Cooper, Jeff P. Chanton, Joel E. Kostka
Hydrogenation Of Organic Matter As A Terminal Electron Sink Sustains High Co2:Ch4 Production Ratios During Anaerobic Decomposition, Rachel M. Wilson, Malak M. Tfaily, Virginia I. Rich, Jason K. Keller, Scott D. Bridgham, Cassandra Medvedeff Zalman, Laura Meredith, Paul J. Hanson, Mark Hines, Laurel Pfeifer-Meister, Scott R. Saleska, Patrick Crill, William T. Cooper, Jeff P. Chanton, Joel E. Kostka
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Once inorganic electron acceptors are depleted, organic matter in anoxic environments decomposes by hydrolysis, fermentation, and methanogenesis, requiring syntrophic interactions between microorganisms to achieve energetic favorability. In this classic anaerobic food chain, methanogenesis represents the terminal electron accepting (TEA) process, ultimately producing equimolar CO2 and CH4 for each molecule of organic matter degraded. However, CO2:CH4 production in Sphagnum-derived, mineral-poor, cellulosic peat often substantially exceeds this 1:1 ratio, even in the absence of measureable inorganic TEAs. Since the oxidation state of C in both cellulose-derived organic matter and acetate is 0, and CO2 has …
Erratum To: Zn (Ii) And Cu (Ii) Adsorption And Retention Onto Iron Oxyhydroxide Nanoparticles: Effects Of Particle Aggregation And Salinity, Rebecca B. Chesne, Christopher S. Kim
Erratum To: Zn (Ii) And Cu (Ii) Adsorption And Retention Onto Iron Oxyhydroxide Nanoparticles: Effects Of Particle Aggregation And Salinity, Rebecca B. Chesne, Christopher S. Kim
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
In the original version of this article errors in Figs. 5 and 9 were identified by the authors. The corrected figures are given.
Nutrient Addition Effects On Tropical Dry Forests: A Mini-Review From Microbial To Ecosystem Scales, Jennifer S. Powers, Kristen K. Becklund, Maria G. Gei, Siddharth B. Iyengar, Rebecca Meyer, Christine S. O'Connell, Erik M. Schilling, Christina M. Smith, Bonnie G. Waring, Leland K. Werden
Nutrient Addition Effects On Tropical Dry Forests: A Mini-Review From Microbial To Ecosystem Scales, Jennifer S. Powers, Kristen K. Becklund, Maria G. Gei, Siddharth B. Iyengar, Rebecca Meyer, Christine S. O'Connell, Erik M. Schilling, Christina M. Smith, Bonnie G. Waring, Leland K. Werden
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Humans have more than doubled inputs of reactive nitrogen globally and greatly accelerated the biogeochemical cycles of phosphorus and metals. However, the impacts of increased element mobility on tropical ecosystems remain poorly quantified, particularly for the vast tropical dry forest biome. Tropical dry forests are characterized by marked seasonality, relatively little precipitation, and high heterogeneity in plant functional diversity and soil chemistry. For these reasons, increased nutrient deposition may affect tropical dry forests differently than wet tropical or temperate forests. Here, we review studies that investigated how nutrient availability affects ecosystem and community processes from the microsite to ecosystem scales …
Biological Degredation Of Acetaldehyde In Southern California Wetlands, Anthony Castagnola, Brandon Lamb, Mary Senstad, Sovandara Hok
Biological Degredation Of Acetaldehyde In Southern California Wetlands, Anthony Castagnola, Brandon Lamb, Mary Senstad, Sovandara Hok
Student Scholar Symposium Abstracts and Posters
Oxygenated hydrocarbons are ubiquitous in the atmosphere with levels ranging from low ppt (acetaldehyde) to low ppb(methanol). As an OH sink and an atmospheric HOx source, oxygenated hydrocarbons have a direct impact on the oxidative capacity of the atmosphere. A better understanding of the processes that produce and destroy these species in natural water would improve our understanding of the role that these systems play in cycling these species into or out of the atmosphere. These species can be lost to chemical, photochemical, and partical mediated (abiotic and biotic) processes in natural waters. Chemical loss and photochemical loss are believed …
Effects Of Ecologically Realistic Heating Profiles On Feeding In The Intertidal Hermit Crab, Pagurus Sameulis, Paige Davis
Effects Of Ecologically Realistic Heating Profiles On Feeding In The Intertidal Hermit Crab, Pagurus Sameulis, Paige Davis
Student Scholar Symposium Abstracts and Posters
The intertidal zone is an ideal habitat to investigate effects of global warming because species living in it are very close to their physiological limits. Initial studies of invertebrate physiological responses to heat stress have employed relatively abrupt increases in temperature. My research investigates effects of ecologically more realistic temperature profiles on feeding in the intertidal hermit crab, Pagurus sameulis. Recent work in the Wright lab showed that feeding in this species is inhibited by an abrupt increase in temperature. Because temperature change in the natural environment of Pagurus is much more gradual, I hypothesize that such a gradual temperature …
Biological Degradation Of Acetaldehyde In Southern California Coastal Waters, Mary Senstad, Sovanndara Hok, Ori Barashy, Catherine D. Clark, Warren J. De Bruyn
Biological Degradation Of Acetaldehyde In Southern California Coastal Waters, Mary Senstad, Sovanndara Hok, Ori Barashy, Catherine D. Clark, Warren J. De Bruyn
Student Scholar Symposium Abstracts and Posters
Oxygenated hydrocarbons are ubiquitous in the atmosphere with levels ranging from low ppt (acetaldehyde) to low ppb (methanol). As an OH sink and an atmospheric HOx and ozone source, oxygenated hydrocarbons have a direct impact on the oxidative capacity of the atmosphere. The oceans are one of the largest sources of uncertainty in current atmospheric budget estimates of these species. A better understanding of the processes that produce and destroy these species in seawater would improve our understanding of the role of the oceans in cycling these species into or out of the atmosphere. We have measured the degradation rate …
Analysis Of Secondary Wastewater Treatment, Jennifer Magana
Analysis Of Secondary Wastewater Treatment, Jennifer Magana
Student Scholar Symposium Abstracts and Posters
At the Irvine Ranch Water District, two types of secondary treatment are utilized: a sludge and Dual Media Filters (DMF) process and Membrane Bioreactor (MBR) process. This study was proposed to analyze the electrical conductivity (EC) of each secondary effluent and possible reasons for differences. After testing the two effluents using an electrical conductivity probe and ion chromatography, it was discovered that there is no significant difference between the two, though secondary treatment raises the nitrate levels in general.
Optical Characterization And Distribution Of Chromophoric Dissolved Organic Matter (Cdom) In Soil Porewater From A Salt Marsh Ecosystem, Catherine D. Clark, Paige Aiona, Jason K. Keller, Warren J. De Bruyn
Optical Characterization And Distribution Of Chromophoric Dissolved Organic Matter (Cdom) In Soil Porewater From A Salt Marsh Ecosystem, Catherine D. Clark, Paige Aiona, Jason K. Keller, Warren J. De Bruyn
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
To characterize chromophoric dissolved organic matter (CDOM) in marsh porewaters and its contribution as a carbon source, optical properties (absorbance, fluorescence indices, 3-dimensional excitation-emission matrices [EEMs]) of soil porewater and surface water were measured in a southern Californian salt marsh. Absorption coefficients and fluorescence intensities were higher in porewater than in overlying surface waters, consistent with higher CDOM concentration at depth. Humic-type peaks A and C were observed in EEMs in all samples, and peak M was observed in surface waters and shallow porewater to -5 cm depth. Fluorescence:absorbance (flu:abs) ratios and spectral slopes (S) decreased across the surface interface, …
Peptide Arrays For Detecting Naphthenic Acids In Oil Sands Process Affected Water, Kamaljit Kaur, Subir Bhattacharjee, Rajesh G. Pillai, Sahar Ahmed, Sarfuddin Azmi
Peptide Arrays For Detecting Naphthenic Acids In Oil Sands Process Affected Water, Kamaljit Kaur, Subir Bhattacharjee, Rajesh G. Pillai, Sahar Ahmed, Sarfuddin Azmi
Pharmacy Faculty Articles and Research
Naphthenic acids (NAs) are water-soluble components of petroleum. The characterization and quantification of NAs by analytical methods have proved quite challenging, whilst the toxic effects of these water-soluble compounds on a variety of organisms adversely affecting reproduction and steroid production is becoming apparent. In this study, we report a fluorescence-based competitive binding method for rapid sensing of the presence of NAs using cellulosic peptide array strips as sensors. The peptide array was designed from sequences derived from the estrogen receptor (ER). Several of these peptides were able to detect the presence of NAs at low micromolar (∼5 mg L−1 …
Zn(Ii) And Cu(Ii) Adsorption And Retention Onto Iron Oxyhydroxide Nanoparticles: Effects Of Particle Aggregation And Salinity, Rebecca B. Chesne, Christopher S. Kim
Zn(Ii) And Cu(Ii) Adsorption And Retention Onto Iron Oxyhydroxide Nanoparticles: Effects Of Particle Aggregation And Salinity, Rebecca B. Chesne, Christopher S. Kim
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Background: Iron oxyhydroxides are commonly found in natural aqueous systems as nanoscale particles, where they can act as effective sorbents for dissolved metals due to their natural surface reactivity, small size and high surface area. These properties make nanoscale iron oxyhydroxides a relevant option for the remediation of water supplies contaminated with dissolved metals. However, natural geochemical processes, such as changes in ionic strength, pH, and temperature, can cause these particles to aggregate, thus affecting their sorption capabilities and remediation potential. Other environmental parameters such as increasing salinity may also impact metal retention, e. g. when particles are transported …
Air-Sea Dimethylsulfide (Dms) Gas Transfer In The North Atlantic: Evidence For Limited Interfacial Gas Exchange At High Wind Speed, T. G. Bell, Warren J. De Bruyn, S. D. Miller, B. Ward, K. Christensen, E. S. Saltzman
Air-Sea Dimethylsulfide (Dms) Gas Transfer In The North Atlantic: Evidence For Limited Interfacial Gas Exchange At High Wind Speed, T. G. Bell, Warren J. De Bruyn, S. D. Miller, B. Ward, K. Christensen, E. S. Saltzman
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Shipboard measurements of eddy covariance dimethylsulfide (DMS) air-sea fluxes and seawater concentration were carried out in the North Atlantic bloom region in June/July 2011. Gas transfer coefficients (k(660)) show a linear dependence on mean horizontal wind speed at wind speeds up to 11 m s(-1). At higher wind speeds the relationship between k(660) and wind speed weakens. At high winds, measured DMS fluxes were lower than predicted based on the linear relationship between wind speed and interfacial stress extrapolated from low to intermediate wind speeds. In contrast, the transfer coefficient for sensible heat did not exhibit this effect. The apparent …
Post-Coring Entrapment Of Modern Air In Some Shallow Ice Cores Collected Near The Firn-Ice Transition: Evidence From Cfc-12 Measurements In Antarctic Firn Air And Ice Cores, Murat Aydin, S. A. Montzka, M. O. Battle, M. B. Williams, Warren J. De Bruyn, J. H. Butler, K. R. Verhulst, C. Tatum, B. K. Gun, D. A. Plotkin, B. D. Hall, Eric S. Saltzman
Post-Coring Entrapment Of Modern Air In Some Shallow Ice Cores Collected Near The Firn-Ice Transition: Evidence From Cfc-12 Measurements In Antarctic Firn Air And Ice Cores, Murat Aydin, S. A. Montzka, M. O. Battle, M. B. Williams, Warren J. De Bruyn, J. H. Butler, K. R. Verhulst, C. Tatum, B. K. Gun, D. A. Plotkin, B. D. Hall, Eric S. Saltzman
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
In this study, we report measurements of CFC-12 (CCl2F2) in firn air and in air extracted from shallow ice cores from three Antarctic sites. The firn air data are consistent with the known atmospheric history of CFC-12. In contrast, some of the ice core samples collected near the firn-ice transition exhibit anomalously high CFC-12 levels. Together, the ice core and firn air data provide evidence for the presence of modern air entrapped in the shallow ice core samples that likely contained open pores at the time of collection. We propose that this is due to closure of the open pores …
Air-Sea Gas Exchange Of Co2 And Dms In The North Atlantic By Eddy Covariance, Scott Miller, Christa Marandino, Warren J. De Bruyn, Eric S. Saltzman
Air-Sea Gas Exchange Of Co2 And Dms In The North Atlantic By Eddy Covariance, Scott Miller, Christa Marandino, Warren J. De Bruyn, Eric S. Saltzman
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
We report the first simultaneous eddy covariance flux measurements of CO2 and dimethylsulfide (DMS) over the open ocean for two North Atlantic cruises. After normalization for Schmidt number, the two gases give essentially identical gas transfer coefficients and wind speed dependences for the wind speed range 2-10 ms(-1). The data indicate a linear relationship between the gas transfer coefficient and mean wind speed, with measured gas transfer coefficients slightly above the Wanninkhof (1992) parameterization, particularly at low wind speeds. Citation: Miller, S., C. Marandino, W. de Bruyn, and E. S. Saltzman (2009), Air-sea gas exchange of CO2 and DMS in …