Physical Sciences and Mathematics Commons^™

Teaching Big History, Richard B. Simon, Mojgan Behmand, Thomas Burke, Esther Quaedackers, Seohyung Kim, Kiowa Bower, Neal Wolfe, James B. Cunningham, Cynthia Taylor, Martin Anderson, J. Daniel May, Philip Novak, Debbie Daunt, Jaime Castner, Ethan Annis, Amy E. Gilbert, Anne Reid, Suzanne Roybal, Alan Schut, Cynthia Brown, Harlan Stelmach

Harlan Stelmach

Alleviation Of Nickel-Induced Stress In Mungbean Through Application Of Gibberellic Acid, Muhammad A. Ali, Hafiz N. Asghar, Muhammad Y. Khan, Muhammad Saleem, Muhammad Naveed, Nabeel Khan Niazi

Dr Nabeel Khan Niazi

Nickel (Ni) is the most eco-toxic and harmful metal for soil biological activity, plant metabolism and health of animals and human beings. Elevated level of Ni in plants causes many nutritional and physiological disorders as well as perturbs in normal balance of phytohormones. Exogenous application of phytohormones can regulate plant growth and reduce inhibitory effect of toxic metals on plants. Therefore present study was conducted to assess the effect of Ni contamination on growth and yield of mungbean and role of gibberellic acid (GA3) to counteract negative effects of Ni contamination. Mungbean seeds were sown in potted soil contaminated with …

Giants Among Micromorphs: Were Cincinnatian (Ordovician, Katian) Small Shelly Phosphatic Faunas Dwarfed?, Benjamin F. Dattilo, Rebecca L. Freeman, Winfried S. Peters, William P. Heimbrock, Bradley Deline, Anthony J. Martin, Jack W. Kallmeyer, Jesse Reeder, Anne Argast

Winfried S. Peters

Approaching A Universal Scaling Relationship Between Fracture Stiffness And Fluid Flow, David Nolte, Laura Pyrak-Nolte

David D Nolte

Geol 112: Hazards, Risks Of Earthquakes And Volcanoes Textbook Alternatives, Donald Reed

Donald Reed

Poster summarizing cost saving textbook alternatives for GEOL 112: Hazards, Risks of Earthquakes and Volcanoes.

Algal Stromatolites In The Willow River Member Of The Lower Ordovician Shakopee Formation Near Chatfield, Minnesota, Usa, Sophia May, Larry Davis, David Brown

David C. Brown

No abstract provided.

Exogenous Application Of Ethylenediamminetetraacetic Acid Enhanced Phytoremediation Of Cadmium By Brassica Napus L., M Farid, S Ali, W Ishaque, M Shakoor, Nabeel Niazi, I Bibi, M Dawood, R Gill, F Abbas

Dr Nabeel Khan Niazi

Performance of B. napus in phytoextraction—an in situ environment friendly technique for the cleanup of contaminated soils—was evaluated through its response to cadmium (Cd) toxicity in combination with a chelator ethylenediamminetetraacetic acid (EDTA) while growing hydroponically in greenhouse conditions under three levels of Cd (0, 10, and 50 µM) and two levels of EDTA (0 and 2.5 mM). Cadmium presence decreased plant growth, biomass and chlorophyll concentrations, while the application of EDTA enhanced plant growth by reducing Cd-induced effects in Cd-stressed plants. Addition of EDTA improved the net photosynthetic and gas exchange capacity of plants under Cd stress. Presence of …

Forecasting Climate Change Impacts On The Distribution Of Wetland Habitat In The Midwestern United States, Heath Garris, Randall Mitchell, Lauchlan Fraser, Linda Barrett

Randall J. Mitchell

Shifting precipitation patterns brought on by climate change threaten to alter the future distribution of wetlands. We developed a set of models to understand the role climate plays in determining wetland formation on a landscape scale and to forecast changes in wetland distribution for the Midwestern United States. These models combined 35 climate variables with 21 geographic and anthropogenic factors thought to encapsulate other major drivers of wetland distribution for the Midwest. All models successfully recreated a majority of the variation in current wetland area within the Midwest, and showed that wetland area was significantly associated with climate, even when …

Acidity Fractions In Acid Sulfate Soils And Sediments: Contributions Of Schwertmannite And Jarosite, Chamindra Vithana, Leigh Sullivan, Richard Bush, Edward Burton

Chamindra Vithana

In Australia, the assessment of acidity hazard in acid sulfate soils requires the estimation of operationally defined acidity fractions such as actual acidity, potential sulfidic acidity, and retained acidity. Acid–base accounting approaches in Australia use these acidity fractions to estimate the net acidity of acid sulfate soils materials. Retained acidity is the acidity stored in the secondary Fe/Al hydroxy sulfate minerals, such as jarosite, natrojarosite, schwertmannite, and basaluminite. Retained acidity is usually measured as either net acid-soluble sulfur (S_NAS) or residual acid soluble sulfur (S_RAS). In the present study, contributions of schwertmannite and jarosite to the …

Liberation Of Acidity And Arsenic From Schwertmannite: Effect Of Fulvic Acid, Chamindra Vithana, Leigh Sullivan, Edward Burton, Richard Bush

Chamindra Vithana

Schwertmannite is one of the major components that produces acidity in acid mine drainage (AMD) and acid sulfate soils (ASS) and is also known to be an effective scavenger of Arsenic (As) in such environments. Fulvic acid (FA) is an active component of natural organic matter (NOM) and is known to interact strongly with both schwertmannite and As. Two main environmental hazards related to schwertmannite are acidity liberation and potential re-mobilization of adsorbed or co-precipitated As upon hydrolysis. This study focused on understanding the behaviour of As-substituted schwertmannite with regard to the potential of acidity liberation, the effect of FA …

Jarosite Quantification In Soils: An Enhanced Sequential Extraction Procedure, Chamindra Vithana, Leigh Sullivan, Richard Bush, Edward Burton

Chamindra Vithana

A two-step sequential extraction procedure established for the quantification of acidity producing ferric and ferrous sulfate minerals such as melanterite and jarosite in acid mine wastes was evaluated for quantification of jarosite spiked in soils. The procedure involves in sequence anoxic water extraction, roasting the solid residue after anoxic water extraction at 550 °C for 1 h, and 4 M HCl extraction of the roasted solid. Soil and quartz samples were spiked with known amounts of synthetic and natural jarosite and their recovery was measured using the suggested two-step sequential extraction procedure. The recoveries of synthetic and natural jarosite were …

Assessment And Behaviour Of Secondary Iron(Iii) Minerals In Acid Sulphate Soil Materials, Chamindra Vithana

Chamindra Vithana

This study examined two aspects of acidity generating secondary Fe(III) minerals (i.e. schwertmannite and jarosite) in acid sulfate soils (ASS) environments: i) accurate identification and quantification, and ii) improving our understanding of their behaviour in ASS.The study showed that current assessment methods have a number of limitations and are not reliable for accurate estimation of both minerals in ASS environments. The study also showed that in natural environments, these minerals can behave in a manner different to current conceptual understanding. The broad implication of this study was identification of the need for development of improved management techniques for ASS.

Schwertmannite In Soil Materials: Limits Of Detection Of Acidified Ammonium Oxalate Method And Differential X-Ray Diffraction, Chamindra Vithana, Leigh Sullivan, Richard Bush, Edward Burton

Chamindra Vithana

Schwertmannite is a secondary iron mineral, found in acid mine drainage (AMD) and acid sulfate soils (ASS), that generates acidity when it transforms to stable mineral phases. Acidity liberated during schwertmannite transformation can seriously diminish water quality and soil health. Acidified ammonium oxalate (AAO) extraction in the dark coupled with differential X-ray diffraction (DXRD) analysis is routinely used to identify and to quantify poorly crystalline iron oxide phases such as schwertmannite in AMD environments. However, management of ASS environments is largely impacted due to lack of reliable methods to identify/quantify schwertmannite in soil materials. Our study aimed to evaluate the …

Stability Of Schwertmannite And Jarosite In An Acidic Landscape: Prolonged Field Incubation, Chamindra Vithana, Leigh Sullivan, Edward Burton, Richard Bush

Chamindra Vithana

Schwertmannite and jarosite are two of the main secondary iron(III) minerals commonly found in acidic, iron and sulfate-rich environments such as acid mine drainage and coastal acid sulfate soils (CASS). Both minerals exert major influence on the water and soil quality in these environments.While there are many studies conducted on the stability of these two minerals under controlled laboratory conditions, the behaviour of schwertmannite and jarosite under field conditions and the factors influencing their behaviour have not been investigated directly. In the present study, we examined the net transformation of introduced schwertmannite and jarosite samples incubated in a typical acidic …

The Quasi-Static Deformation, Failure, And Fracture Behavior Of Titanium Alloy Gusset Plates Containing Bolt Holes, Therese Hurtuk, Craig Menzemer, Anil Patnaik, Tirumalai Srivatsan, Kannan Manigandan, T. Quick

Craig Menzemer

In this article, the influence of bolt holes, specifically their number and layout on strength, deformation, and final fracture behavior of titanium alloy gusset plates under the influence of an external load is presented and discussed. Several plates having differences in both the number and layout of the bolt holes were precision machined and then deformed under quasi-static loading. The specific influence of number of bolt holes and their layout on maximum load-carrying capability and even fracture load was determined. The conjoint influence of bolt number, bolt layout pattern, nature of loading, contribution from local stress concentration, and intrinsic microstructural …

Arsenic Mobility During Flooding Of Contaminated Soil: The Effect Of Microbial Sulfate Reduction, Edward Burton, Scott Johnston, Benjamin Kocar

Associate Professor Edward D Burton

In floodplain soils, As may be released during flooding-induced soil anoxia, with the degree of mobilization being affected by microbial redox processes such as the reduction of As(V), Fe(III), and SO42–. Microbial SO42– reduction may affect both Fe and As cycling, but the processes involved and their ultimate consequences on As mobility are not well understood. Here, we examine the effect of microbial SO42 reduction on solution dynamics and solid-phase speciation of As during flooding of an As-contaminated soil. In the absence of significant levels of microbial SO42– reduction, flooding caused increased Fe(II) and As(III) concentrations over a 10 week …

Seawater Inundation Of Coastal Floodplain Sediments: Short-Term Changes In Surface Water And Sediment Geochemistry, Vanessa Wong, Scott Johnston, Edward Burton, Phillip Hirst, Leigh Sullivan, Richard Bush, Mark Blackford

Associate Professor Edward D Burton

Coastal floodplains are highly vulnerable to seawater inundation as a result of storm surge and sea-level rise due to their low elevation and proximity to the coastline. Intact soil cores from a levee, acid-sulfate soil scald and four backswamp sites on a coastal floodplain in eastern Australia were inundated with artificial seawater treatments (0%, 50% and 100%) for 14 days to examine the short term consequences for surface water and floodplain sediment geochemistry. All sites displayed an initial decrease in surface water pH following inundation with 50% and 100% seawater. In addition, higher concentrations of trace metals (Al, Fe, Mn, …

Forecasting Climate Change Impacts On The Distribution Of Wetland Habitat In The Midwestern United States, Heath Garris, Randall Mitchell, Lauchlan Fraser, Linda Barrett

Linda R. Barrett

Shifting precipitation patterns brought on by climate change threaten to alter the future distribution of wetlands. We developed a set of models to understand the role climate plays in determining wetland formation on a landscape scale and to forecast changes in wetland distribution for the Midwestern United States. These models combined 35 climate variables with 21 geographic and anthropogenic factors thought to encapsulate other major drivers of wetland distribution for the Midwest. All models successfully recreated a majority of the variation in current wetland area within the Midwest, and showed that wetland area was significantly associated with climate, even when …

Controls On Trace Metal Authigenic Enrichment In Reducing Sediments: Insights From Modern Oxygen-Deficient Settings, Susan Little, Derek Vance, Timothy Lyons, James Mcmanus

James McManus

Any effort to reconstruct Earth history using variations in authigenic enrichments of redox-sensitive and biogeochemically important trace metals must rest on a fundamental understanding of their modern oceanic and sedimentary geochemistry. Further, unravelling the multiple controls on sedimentary enrichments requires a multi-element approach. Of the range of metals studied, most is known about the behavior of Fe, Mn, and Mo. In this study, we compare the authigenic enrichment patterns of these elements with a group whose behavior is not as well defined (Cd, Cu, Zn, and Ni) in three oxygen-poor settings: the Black Sea, the Cariaco Basin (Venezuela), and the …

The Sedimentary Flux Of Dissolved Rare Earth Elements To The Ocean, April Abbott, Brian Haley, James Mcmanus, Clare Reimers

James McManus

We determined pore fluid rare earth element (REE) concentrations in near-surface sediments retrieved from the continental margin off Oregon and California (USA). These sites represent shelf-to-slope settings, which lie above, within, and below the oxygen minimum zone of the Northeast Pacific. The sediments are characterized by varying degrees of net iron reduction, with pore fluids from the shelf sites being generally ferruginous, and the slope sediments having less-pronounced iron reduction zones that originate deeper in the sediment package. REE concentrations show maxima in shallow (upper 2–10 cm) subsurface pore fluids across all sites with concentrations that rise more than two …

On The Isotope Composition Of Reactive Iron In Marine Sediments: Redox Shuttle Versus Early Diagenesis, Florian Shultz, Silke Severman, James Mcmanus, Anna Nofke, Ulrike Lomnitz, Christian Hensen

James McManus

The isotope composition of reactive iron (Fe) in marine sediments and sedimentary rocks is a promising tool for identifying Fe sources and sinks across ocean basins. In addition to cross-basinal Fe redistribution, which can modify Fe isotope signatures, Fe minerals also undergo diagenetic redistribution during burial. The isotope fractionation associated with this redistribution does not affect the bulk isotope composition, but complicates the identification of mineral- specific isotope signatures. Here, we present new Fe isotope data for Peru margin sediments and revisit previously published data for sediments from the California margin to unravel the impact of early diagenesis on Fe …

The Quasi-Static Deformation, Failure, And Fracture Behavior Of Titanium Alloy Gusset Plates Containing Bolt Holes, Therese Hurtuk, Craig Menzemer, Anil Patnaik, Tirumalai Srivatsan, Kannan Manigandan, T. Quick

Anil Patnaik

In this article, the influence of bolt holes, specifically their number and layout on strength, deformation, and final fracture behavior of titanium alloy gusset plates under the influence of an external load is presented and discussed. Several plates having differences in both the number and layout of the bolt holes were precision machined and then deformed under quasi-static loading. The specific influence of number of bolt holes and their layout on maximum load-carrying capability and even fracture load was determined. The conjoint influence of bolt number, bolt layout pattern, nature of loading, contribution from local stress concentration, and intrinsic microstructural …

Geochronology Of Hemphillian-Blancan Aged Strata, Guanajuato, Mexico, And Implications For Timing Of The Great American Biotic Interchange, Bart Kowallis, John Flynn, Clarita Nunez, Oscar Carranza-Castaneda, Wade Miller, Carl Swisher, Everett Lindsay

Bart J Kowallis

We present new geochronologic magnetostratigraphy, fission-track and 40Ar/39Ar radioisotopic dates, biostratigraphy)bdata constraining the age of three separate sequences and a composite section from Guanajuato, Mexico. Those data make this one of the most complete and precisely age-calibrated sequences in North America spanning the Hemphillian/Blancan North American Land Mammal “Age” (NALMA) boundary interval, and the data further constrain the timing and pattern of the Great American Biotic Interchange (GABI). In total, 196 samples (77 sites) were used to construct the magnetic polarity stratigraphies, with eight fission-track analyses and four new 40Ar/39Ar radioisotopic dates. The sections sampled are possibly latest Miocene to …

Contrasting Silicic Magma Series In Miocene-Pliocene Ash Deposits In The San Miguel De Allende Graben, Guanajuato, Mexico, Eric Christiansen, Bart Kowallis, Aaron Adams, Oscar Carranza-Castaneda, Wade Miller

Bart J Kowallis

The San Miguel de Allende graben, Guanajuato, Mexico, contains numerous rhyolitic volcanic ash beds. Electron microprobe and x-ray fluorescence analyses of glass shards from 14 localities, combined with mineralogic, stratigraphic, radiometric, and paleomagnetic data, allow us to correlate the ash beds (and the intervening sedimentary strata and fossils), understand the timing of volcanism, date the age of extension, and better understand the tectonic and volcanic evolution of central Mexico. Our analyses reveal that at least six separate eruptions of rhyolitic ash occurred during the Late Miocene and Pliocene (5-3 Ma) while the San Miguel Allende basin was subsiding. The fallout …

Record Of Archaeal Activity At The Serpentinite-Hosted Lost City Hydrothermal Field, S. Méhay, G. Früh-Green, Susan Lang, S. Bernasconi, W. Brazelton, M. Schrenk, P. Schaeffer, P. Adam

Susan Q. Lang

No abstract provided.

H2/Ch4 Ratios Cannot Reliably Distinguish Abiotic Vs. Biotic Methane In Natural Hydrothermal Systems, Susan Lang, G. Früh-Green, D. Kelley, M. Lilley, G. Proskurowski, E. Reeves

Susan Q. Lang

No abstract provided.

Microbial Utilization Of Abiogenic Carbon And Hydrogen In A Serpentinite-Hosted System, Susan Lang, G. Früh-Green, S. Bernasconi, M. Lilley, G. Proskurowski, S. Méhay, D. Butterfield

Susan Q. Lang

No abstract provided.

Serpentinization, Carbon, And Deep Life, M. Schrenk, W. Brazelton, Susan Lang

Susan Q. Lang

No abstract provided.

Elevated Concentrations Of Formate, Acetate And Dissolved Organic Carbon Found At The Lost City Hydrothermal Field, Susan Lang, D. Butterfield, M. Schulte, D. Kelley, M. Lilley

Susan Q. Lang

No abstract provided.

Probing For Life In The Ocean Crust With The Lexen Program, H. Johnson, J. Baross, T. Bjorkland, W. Brazelton, J. Huber, M. Pruis, Susan Lang, F. Mccrosky, M. Mehta, D. Butterfield, A. Bowen, J. Howland, W. Martin, K. Roe, C. Channing, P. Kalk, C. Kammerer, R. Light, V. Miller, M. Mccarthy, B. Moore, M. Sharma, J. Voit

Susan Q. Lang

No abstract provided.