Physical Sciences and Mathematics Commons^™

Feldspathic Rocks On Mars: Compositional Constraints From Infrared Spectroscopy And Possible Formation Mechanisms, Deanne Rogers, Hanna Nekvasil

Department of Geosciences Faculty Publications

Rare feldspar-dominated surfaces on Mars were previously reported based on near-infrared (NIR) spectral data and were interpreted to consist of anorthosite or felsic rocks. Using thermal infrared (TIR) data over the feldspar detections with the largest areal extent in Nili Patera and Noachis Terra, we rule out felsic interpretations. Basaltic or anorthositic compositions are consistent with TIR measurements, but the geologic contexts for these regions do not support a plutonic origin. Laboratory NIR spectral measurements demonstrate that large plagioclase crystals (>~840 μm) can be detected in mixtures with as much as 50 vol % mafics, which is higher than …

Haverstraw Bay Benthic Mapping Project Gis Data, Robert M. Cerrato

SoMAS Research Data

High-resolution backscatter and bathymetric maps created by multibeam and sidescan sonar surveys were used to identify five different seafloor bottom types within Haverstraw Bay. Grab samples were collected within these areas to characterize sediment properties and macrofauna. Selected sampling locations were revisited and seafloor images were obtained with an HD underwater camera. Multivariate analysis was used to identify the most important factors explaining variations in community structure. Results indicated that categorical variables defining bottom types, grain size, and water depth can explain about 42% of community structure variation. In addition, shell length data collected for Rangia cuneata, an introduced species, …

The Module Isomorphism Problem Reconsidered, Peter A. Brooksbank

Faculty Journal Articles

Algorithms to decide isomorphism of modules have been honed continually over the last 30 years, and their range of applicability has been extended to include modules over a wide range of rings. Highly efficient computer implementations of these algorithms form the bedrock of systems such as GAP and MAGMA, at least in regard to computations with groups and algebras. By contrast, the fundamental problem of testing for isomorphism between other types of algebraic structures -- such as groups, and almost any type of algebra -- seems today as intractable as ever. What explains the vastly different complexity status of the …

Lithostratigraphic Investigation And Components Of A Complete Petroleum System Within An Upper Devonian Carbonate-Evaporite Sequence : The Birdbear Formation, Williston Basin, North Dakota, Benjamin L. Engleman

Theses and Dissertations

The Birdbear Formation of the Williston Basin of southwestern North Dakota represents one carbonate-evaporite sequence of the Late Devonian. The formation was deposited during regression on a broad, shallow epeiric shelf and is composed principally of dolomite, limestone and anhydrite. The Birdbear Formation is conformable with the Duperow Formation below and the Three Forks Formation above. The designations of 17 lithofacies form the context for describing hydrocarbon generation, migration and accumulation. Rock-Eval 6 and total organic carbon of 42 samples were used to identify the quality of source rocks present in the formation. Good and excellent source rocks were identified …

Divergent Responses Of Atlantic Coastal And Oceanic Synechococcus To Iron Limitation, Katherine R. M. Mackey, Anton F. Post, Matthew R. Mcilvin, Gregory A. Cutter, Seth G. John, Mak A. Saito

OES Faculty Publications

Marine Synechococcus are some of the most diverse and ubiquitous phytoplankton, and iron (Fe) is an essential micronutrient that limits productivity in many parts of the ocean. To investigate how coastal and oceanic Atlantic Synechococcus strains acclimate to Fe availability, we compared the growth, photophysiology, and quantitative proteomics of two Synechococcus strains from different Fe regimes. Synechococcus strain WH8102, from a region in the southern Sargasso Sea that receives substantial dust deposition, showed impaired growth and photophysiology as Fe declined, yet used few acclimation responses. Coastal WH8020, from the dynamic, seasonally variable New England shelf, displayed a multitiered, hierarchical cascade …

The Relative Importance Of Methanogenesis In The Decomposition Of Organic Matter In Northern Peatlands, J. Elizabeth Corbett, Malak M. Tfaily, David J. Burdige, Paul H. Glaser, Jeffrey P. Chanton

OES Faculty Publications

Using an isotope-mass balance approach and assuming the equimolar production of CO₂ and CH₄ from methanogenesis (e.g., anaerobic decomposition of cellulose), we calculate that the proportion of total CO₂ production from methanogenesis varies from 37 to 83% across a variety of northern peatlands. In a relative sense, methanogenesis was a more important pathway for decomposition in bogs (80 ± 13% of CO₂ production) than in fens (64 ± 5.7% of CO₂ production), but because fens contain more labile substrates they may support higher CH4 production overall. The concentration of CO₂ produced from methanogenesis (CO …

Predicting Effects Of Ocean Warming, Acidification, And Water Quality On Chesapeake Region Eelgrass, Richard C. Zimmerman, Victoria J. Hill, Charles L. Gallegos

OES Faculty Publications

Although environmental requirements of seagrasses have been studied for years, reliable metrics for predicting their response to current or future conditions remain elusive. Eelgrass (Zostera marina L.) populations of the Chesapeake region lie near the southern limit of their range in the Western North Atlantic, exposing them to increasing thermal stress as the climate warms. However, CO₂ stimulated photosynthesis may offset some of the negative effects of temperature stress. The combined effects of temperature, CO₂, and light availability controlled by water quality and epiphytes were explored using GrassLight, a bio-optical model that provided a predictive …

Tropical North Atlantic Subsurface Warming Events As A Fingerprint For Amoc Variability During Marine Isotope Stage 3, Andrew O. Parker, Matthew W. Schmidt, Ping Chang

OES Faculty Publications

The role of Atlantic Meridional Overturning Circulation (AMOC) as the driver of Dansgaard-Oeschger (DO) variability that characterized Marine Isotope Stage 3 (MIS 3) has long been hypothesized. Although there is ample proxy evidence suggesting that DO events were robust features of glacial climate, there is little data supporting a link with AMOC. Recently, modeling studies and subsurface temperature reconstructions have suggested that subsurface warming across the tropical North Atlantic can be used to fingerprint a weakened AMOC during the deglacial because a reduction in the strength of the western boundary current allows warm salinity maximum water of the subtropical gyre …

The Influence Of Sea Ice And Snow Cover And Nutrient Availability On The Formation Of Massive Under-Ice Phytoplankton Blooms In The Chukchi Sea, Jinlun Zhang, Carin Ashjian, Robert Campbell, Yvette H. Spitz, Michael Steele, Victoria Hill

OES Faculty Publications

A coupled biophysical model is used to examine the impact of changes in sea ice and snow cover and nutrient availability on the formation of massive under-ice phytoplankton blooms (MUPBs) in the Chukchi Sea of the Arctic Ocean over the period 1988–2013. The model is able to reproduce the basic features of the ICESCAPE (Impacts of Climate on EcoSystems and Chemistry of the Arctic Pacific Environment) observed MUPB during July 2011. The simulated MUPBs occur every year during 1988–2013, mainly in between mid-June and mid-July. While the simulated under-ice blooms of moderate magnitude are widespread in the Chukchi Sea, MUPBs …

Interpretation Of Complexometric Titration Data: An Intercomparison Of Methods For Estimating Models Of Trace Metal Complexation By Natural Organic Ligands, I. Pižeta, S. G. Sander, R. J. M. Hudson, D. Omanović, O. Baars, K. A. Barbeau, K. N. Buck, R. M. Bundy, G. Carrasco, P. L. Croot

OES Faculty Publications

With the common goal of more accurately and consistently quantifying ambient concentrations of free metal ions and natural organic ligands in aquatic ecosystems, researchers from 15 laboratories that routinely analyze trace metal speciation participated in an intercomparison of statistical methods used to model their most common type of experimental dataset, the complexometric titration. All were asked to apply statistical techniques that they were familiar with to model synthetic titration data that are typical of those obtained by applying state-of-the-art electrochemical methods – anodic stripping voltammetry (ASV) and competitive ligand equilibration-adsorptive cathodic stripping voltammetry (CLE-ACSV) – to the analysis of natural …

Living On The Margin In The Anthropocene: Engagement Arenas For Sustainability Research And Action At The Ocean-Land Interface, B. C. Glavovic, K. Limburg, K-K. Liu, K-C. Emeis, H. Thomas, H. Kremer, B. Avril, J. Zhang, M. R. Mulholland, M. Glaser, D. P. Swaney

OES Faculty Publications

The advent of the Anthropocene underscores the need to develop and implement transformative governance strategies that safeguard the Earth's life-support systems, most critically at the ocean-land interface - the Margin. The seaward realm of the Margin is the new frontier for resource exploitation and colonization to meet the needs of coastal nations and humanity overall. Here, we spotlight the pivotal role of the Margin for planetary resilience and sustainability, highlight priority issues, and outline a research strategy which aims to: (a) better understand Margin social-ecological systems; (b) guide sustainable development of Margin resources; (c) design governance regimes to reverse unsustainable …

The Geotraces Intermediate Data Product 2014, Edward Mawji, Reiner Schlitzer, Elena M. Dodas, Cyril Abadie, Wafa Abouchami, Robert F. Anderson, Gregory A. Cutter

OES Faculty Publications

The GEOTRACES Intermediate Data Product 2014 (IDP2014) is the first publicly available data product of the international GEOTRACES programme, and contains data measured and quality controlled before the end of 2013. It consists of two parts: (1) a compilation of digital data for more than 200 trace elements and isotopes (TEls) as well as classical hydrographic parameters, and (2) the eGEOTRACES Electronic Atlas providing a strongly inter-linked on-line atlas including more than 300 section plots and 90 animated 3D scenes. The IDP2014 covers the Atlantic, Arctic, and Indian oceans, exhibiting highest data density in the Atlantic. The TEI data in …

Genetic Indicators Of Iron Limitation In Wild Populations Of Thalassiosira Oceanica From The Northeast Pacific Ocean, P. Dreux Chappell, Leann P. Whitney, Joselynn R. Wallace, Adam I. Darer, Samua Jean-Charles, Bethany D. Jenkins

OES Faculty Publications

Assessing the iron (Fe) nutritional status of natural diatom populations has proven challenging as physiological and molecular responses can differ in diatoms of the same genus. We evaluated expression of genes encoding flavodoxin (FLDA1) and an Fe-starvation induced protein (ISIP3) as indicators of Fe limitation in the marine diatom Thalassiosira oceanica. The specificity of the response to Fe limitation was tested in cultures grown under Fe-and macronutrient-deficient conditions, as well as throughout the diurnal light cycle. Both genes showed a robust and specific response to Fe limitation in laboratory cultures and were detected in small volume samples collected from …

Iron Deficiency Increases Growth And Nitrogen-Fixation Rates Of Phosphorus-Deficient Marine Cyanobacteria, Nathan S. Garcia, Feixue Fu, Peter N. Sedwick, David A. Hutchins

OES Faculty Publications

Marine dinitrogen (N²)-fixing cyanobacteria have large impacts on global biogeochemistry as they fix carbon dioxide (CO₂) and fertilize oligotrophic ocean waters with new nitrogen. Iron (Fe) and phosphorus (P) are the two most important limiting nutrients for marine biological N₂ fixation, and their availabilities vary between major ocean basins and regions. A long-standing question concerns the ability of two globally dominant N₂-fixing cyanobacteria, unicellular Crocosphaera and filamentous Trichodesmium, to maintain relatively high N₂-fixation rates in these regimes where both Fe and P are typically scarce. We show that under P-deficient …

Evaluation Of The Effects Of A Plasma Activated Medium On Cancer Cells, S. Mohades, M. Laroussi, J. Sears, N. Barekzi, H. Razavi

Electrical & Computer Engineering Faculty Publications

The interaction of low temperature plasma with liquids is a relevant topic of study to the field of plasma medicine. This is because cells and tissues are normally surrounded or covered by biological fluids. Therefore, the chemistry induced by the plasma in the aqueous state becomes crucial and usually dictates the biological outcomes. This process became even more important after the discovery that plasma activated media can be useful in killing various cancer cell lines. Here, we report on the measurements of concentrations of hydrogen peroxide, a species known to have strong biological effects, produced by application of plasma to …

Killing Adherent And Nonadherent Cancer Cells With The Plasma Pencil, Mounir Laroussi, Soheila Mohades, Nazir Barekzi

Electrical & Computer Engineering Faculty Publications

The application of low temperature plasmas in biology and medicine may lead to a paradigm shift in the way various diseases can be treated without serious side effects. Low temperature plasmas generated in gas mixtures that contain oxygen or air produce several chemically reactive species that have important biological implications when they interact with eukaryotic or prokaryotic cells. Here, a review of the effects of low temperature plasma generated by the plasma pencil on different cancerous cells is presented. Results indicate that plasma consistently shows a delayed killing effect that is dose dependent. In addition, there is some evidence that …

Identification Of Magnetite In Lunar Regolith Breccia 60016: Evidence For Oxidized Conditions At The Lunar Surface, Katherine H. Joy, Channon Visscher, Michael E. Zolensky, Takashi Mikouchi, Kenji Hagiya, Kazumasa Ohsumi, David A. Kring

Faculty Work Comprehensive List

Lunar regolith breccias are temporal archives of magmatic and impact bombardment processes on the Moon. Apollo 16 sample 60016 is an ‘ancient’ feldspathic regolith breccia that was converted from a soil to a rock at ~3.8 Ga. The breccia contains a small (70 × 50 μm) rock fragment composed dominantly of an Fe-oxide phase with disseminated domains of troilite. Fragments of plagioclase (An95-97), pyroxene (En74-75, Fs21-22,Wo3-4) and olivine (Fo66-67) are distributed in and adjacent to the Fe-oxide. The silicate minerals have lunar compositions that are similar to anorthosites. Mineral chemistry, synchrotron X-ray Absorption Near Edge Spectroscopy (XANES) and X-ray Diffraction …

Iron Supply And Demand In Antarctic Shelf Ecosystem, D. J. Mcgillicuddy Jr., Peter N. Sedwick, Michael S. Dinniman, K. R. Arrigo, T. S. Bibby, B. J. W. Greenan, Eileen E. Hofmann, John M. Klinck, W. O. Smith Jr., S. L. Mack, C. M. Marsay, B. M. Sohst, G. L. Van Dijken

OES Faculty Publications

The Ross Sea sustains a rich ecosystem and is the most productive sector of the Southern Ocean. Most of this production occurs within a polynya during the November-February period, when the availability of dissolved iron (dFe) is thought to exert the major control on phytoplankton growth. Here we combine new data on the distribution of dFe, high-resolution model simulations of ice melt and regional circulation, and satellite-based estimates of primary production to quantify iron supply and demand over the Ross Sea continental shelf. Our analysis suggests that the largest sources of dFe to the euphotic zone are wintertime mixing and …

Predicting Carbon Isotope Discrimination In Eelgrass (Zostera Marina L.) From The Environmental Parameters- Light, Flow, And [Dic], Meredith L. Mcpherson, Richard C. Zimmerman, Victoria J. Hill

OES Faculty Publications

Isotopic discrimination against ¹³C during photosynthesis is determined by a combination of environmental conditions and physiological mechanisms that control delivery of CO₂ to RUBISCO. This study investigated the effects of light, flow, dissolved inorganic carbon (DIC) concentration, and its speciation, on photosynthetic carbon assimilation of Zostera marinaL. (eelgrass) using a combination of laboratory experiments and theoretical calculations leading to a mechanistic understanding of environmental conditions that influence leaf carbon uptake and determine leaf stable carbon isotope signatures δ¹³C. Photosynthesis was saturated with respect to flow at low velocity ~ 3 cm s^-1, but …

Understanding Ocean Acidification Impacts On Organismal To Ecological Scales, Andreas J. Andersson, David I. Kline, Peter J. Edmunds, Stephen D. Archer, Nina Bednarsek, Robert C. Carpenter, Meg Chadsey, Philip Goldstein, Andrea G. Grottoli, Thomas P. Hurst, Andrew L. King, Janet E. Kübler, Ilsa B. Kuffner, Katherine R.M. Mackey, Bruce A. Menge, Adina Paytan, Ulf Riebesell, Astrid Schnetzer, Mark E. Warner, Richard C. Zimmerman

OES Faculty Publications

Ocean acidification (OA) research seeks to understand how marine ecosystems and global elemental cycles will respond to changes in seawater carbonate chemistry in combination with other environmental perturbations such as warming, eutrophication, and deoxygenation. Here, we discuss the effectiveness and limitations of current research approaches used to address this goal. A diverse combination of approaches is essential to decipher the consequences of OA to marine organisms, communities, and ecosystems. Consequently, the benefits and limitations of each approach must be considered carefully. Major research challenges involve experimentally addressing the effects of OA in the context of large natural variability in seawater …

Heterotrophic And Autotrophic Contribution To Dinitrogen Fixation In The Gulf Of Aqaba, Eyal Rahav, Barak Herut, Margaret R. Mulholland, Natalia Belkin, Hila Elifantz, Ilana Berman-Frank

OES Faculty Publications

We evaluated the seasonal contribution of heterotrophic and autotrophic diazotrophy to the total dinitrogen (N₂) fixation in the photic zone of a pelagic station in the northern Gulf of Aqaba, Red Sea. N₂ fixation rates were highest during a Trichodesmium bloom in winter (0.7 nmol N l^-1 d^-1), decreased 7-fold 1 wk later throughout the upper 200 m (~0.1 nmol N l^-1) d^-1), and were significantly coupled with both primary and bacterial productivity. N₂ fixation rates were generally higher in the upper 200 m (~0.4 nmol N l^{-1 …}

New Tracer To Estimate Community Predation Rates Of Phagotrophic Protists, Alexander B. Bochdansky, Melissa A. Clouse

OES Faculty Publications

Predation of eukaryotic microbes on prokaryotes is one of the most important trophic interactions on Earth, representing a major mortality term and shaping morphology and composition of prokaryotic communities. Here we introduce and validate a new tracer to determine predation rates on prokaryotes. Minicells of Escherichia coli marked with a bright green fluorescent protein (GFP) vector have many operational advantages over previously used prey analogs such as fluorescently labeled bacteria. GFP-minicells are similar in size to naturally occurring bacteria from a variety of environments including the oligotrophic open ocean and the deep sea. They are relatively stable against microbial and …

Proof-Of-Concept Of Environmental Dna Tools For Atlantic Sturgeon Management, Jameson Hinkle

Theses and Dissertations

Abstract

The Atlantic Sturgeon (Acipenser oxyrinchus oxyrinchus, Mitchell) is an anadromous species that spawns in tidal freshwater rivers from Canada to Florida. Overfishing, river sedimentation and alteration of the river bottom have decreased Atlantic Sturgeon populations, and NOAA lists the species as endangered. Ecologists sometimes find it difficult to locate individuals of a species that is rare, endangered or invasive. The need for methods less invasive that can create more resolution of cryptic species presence is necessary. Environmental DNA (eDNA) is a non-invasive means of detecting rare, endangered, or invasive species by isolating nuclear or mitochondrial DNA (mtDNA) from the …

Long-Term Effects Of Land Cover Change On Fish Assemblage Structure In The Piedmont And Coastal Plain Regions Of Virginia, Samuel F. Stickley

Theses and Dissertations

Changes in land cover and fish assemblage structure were assessed across two spatial and temporal scales in the Piedmont and Coastal Plain regions of the Chesapeake Bay watershed in Virginia. A long-term, local study (1953 to 2014) on the Tuckahoe Creek watershed used digitized aerial photography and satellite images (Landsat 5 TM and Landsat 8 OLI/TIRS) to quantify land cover change for five nested catchments in 1953, 1990, and 2014. Instream fish collections from 1958, 1990, and 2014 were utilized to assess a variety of fish assemblage metrics for each of the five catchments, and analyses were performed to assess …

Question 1: Star Speeds; Question 2: Slurping Gasoline, Larry Weinstein

Physics Faculty Publications

One piece of evidence that the center of our galaxy contains a super-massive black hole came from measuring the speed of a star orbiting that black hole. What is the maximum speed of that star?

If instead of carrying their gas in fuel tanks, cars “slurped up” a stream of gas as they drove, how thick a stream of gas would each car need?

Question 1: "Up" — A Fermi Question About Buoyancy; Question 2: Traffic Jams, Larry Weinstein

Physics Faculty Publications

Is it possible for a house to fly by the uplift of balloons, like in the movie "Up"? (written by R. Allart, A. Cazenave, and A. Müller, University of Geneva)

How much total time do Americans spend waiting in traffic each year? What is the total cost of this time?

Question 1: Kill The K-Cup; Question 2: Water Cooling, Larry Weinstein

Physics Faculty Publications

According to KillTheKCup.org, single-use non-recyclable Keurig K-cups “are killing our planet.” How large is the environmental impact of K-Cups?

How much more cooling do you get from drinking cold rather than room-temperature water on a hot day? How much do you sweat per day when the ambient temperature is about 35 °C (95 °F)?

Question 1: Shaving Time; Question 2: Half-Filling The Gas Tank, Larry Weinstein

Physics Faculty Publications

How much total time does a typical American spend shaving during his or her life? How much total time per year do Americans spend shaving?

How much money can you save by only half-filling your car's gas tank to reduce weight?

Characterization Of Prose By Rhetorical Structure For Machine Learning Classification, James Java

CCAC Theses and Dissertations

Measures of classical rhetorical structure in text can improve accuracy in certain types of stylistic classification tasks such as authorship attribution. This research augments the relatively scarce work in the automated identification of rhetorical figures and uses the resulting statistics to characterize an author's rhetorical style. These characterizations of style can then become part of the feature set of various classification models.

Our Rhetorica software identifies 14 classical rhetorical figures in free English text, with generally good precision and recall, and provides summary measures to use in descriptive or classification tasks. Classification models trained on Rhetorica's rhetorical measures paired with …

Anisotropy Reversal Of The Upper Critical Field At Low Temperatures And Spin-Locked Superconductivity In K₂Cr₃As₃, F. F. Balakirev, T. Kong, M. Jaime, R. D. Mcdonald, C. H. Mielke, A. Gurevich, P. C. Canfield, S. L. Bud'ko

Physics Faculty Publications

We report measurements of the anisotropic upper critical field H_c2(T) for K₂Cr₃As₃ single crystals up to 60 T and T > 0.6K. Our results show that the upper critical field parallel to the Cr chains, H^∥_c2(T), exhibits a paramagnetically limited behavior, whereas the shape of the H^⊥_c2(T) curve (perpendicular to the Cr chains) has no evidence of paramagnetic effects. As a result, the curves H^⊥_c2(T) and H^∥_c2(T) cross at T ≈ 4K, so that the anisotropy parameter _H(T)=H …