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Faculty Publications

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Articles 121 - 150 of 383

Full-Text Articles in Earth Sciences

Magma Reservoir Formation And Evolution At A Slow-Spreading Center (Atlantis Bank, Southwest Indian Ridge), Marine Boulanger, Lydéric France, Jeremy R.L. Deans, Carlotta Ferrando, C. Johan Lissenberg, Anette Von Der Handt Sep 2020

Magma Reservoir Formation And Evolution At A Slow-Spreading Center (Atlantis Bank, Southwest Indian Ridge), Marine Boulanger, Lydéric France, Jeremy R.L. Deans, Carlotta Ferrando, C. Johan Lissenberg, Anette Von Der Handt

Faculty Publications

© Copyright © 2020 Boulanger, France, Deans, Ferrando, Lissenberg and von der Handt. Several ODP-IODP expeditions drilled oceanic core complexes interpreted as exhumed portions of lower crust close to the ridge axis, and provide the community with invaluable sampling opportunity for further constraining magmatic processes involved in the formation of the slow-spreading lower oceanic crust. ODP Hole 735B presents the most primitive lithologies sampled at Atlantis Bank oceanic core complex (Southwest Indian Ridge) in a ∼250 m thick section that was previously interpreted as a single crustal intrusion. We combined detailed structural and petrographic constraints with whole rock and in …

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Geochemical Characterization Of Base Metals In Stream Water And Sediments In The Caddo Lake Watershed, Cass, Harrison, And Marion Counties, Texas, Melinda S. Faulkner, Melanie L. Ertons, Joseph D. Watkins Sep 2020

Geochemical Characterization Of Base Metals In Stream Water And Sediments In The Caddo Lake Watershed, Cass, Harrison, And Marion Counties, Texas, Melinda S. Faulkner, Melanie L. Ertons, Joseph D. Watkins

Faculty Publications

The Caddo Lake watershed is located in northeastern Texas and encompasses much of Cass, Harrison, and Marion counties. The watershed is drained by major streams and tributaries flowing in an easterly direction over Eocene-aged rocks and sediments of the Wilcox and Claiborne groups, and empty into the western arm of Caddo Lake. Since 1995, Caddo Lake and some of its tributaries have been included on the State of Texas Clean Water Act 303(d) list by the Texas Commission on Environmental Quality (TCEQ) for impairment due to mercury content in edible tissue, depressed dissolved oxygen, base metal concentrations, and low pH …

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Investigation Of Pore-Scale Caco3 Distributions And Their Effects On Stiffness And Permeability Of Sands Treated By Microbially Induced Carbonate Precipitation (Micp), Hai Lin, Muhannad Suleiman, Derick G. Brown Aug 2020

Investigation Of Pore-Scale Caco3 Distributions And Their Effects On Stiffness And Permeability Of Sands Treated By Microbially Induced Carbonate Precipitation (Micp), Hai Lin, Muhannad Suleiman, Derick G. Brown

Faculty Publications

Physical properties of MICP-treated sands are controlled by CaCO3 distributions in pore space, which remain relatively unexplored. CaCO3 can deposit at the particles' contact area (contact-cementing), coat sand particles (grain-coating), or create a cementation bridge between soil grains (matrix-supporting). The objectives of this paper are to determine the dominant CaCO3 distributions in pore space and investigate the effects of CaCO3 distributions on the small-strain stiffness (measured by S-and P-wave velocities) and permeability of MICP-treated sands. To achieve these objectives, cemented-sand and uncemented-sand models combined with three ideal CaCO3 distributions (contact-cementing, grain-coating, and matrix-supporting) were used to estimate the S-and P-wave …

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Traffic Impacts Of The Covid-19 Pandemic: Statewide Analysis Of Social Separation And Activity Restriction, Scott Parr, Brian Wolshon, John Renne, Pamela Murray-Tuite, Karl Kim Aug 2020

Traffic Impacts Of The Covid-19 Pandemic: Statewide Analysis Of Social Separation And Activity Restriction, Scott Parr, Brian Wolshon, John Renne, Pamela Murray-Tuite, Karl Kim

Faculty Publications

The COVID-19 pandemic resulted in significant social and economic impacts throughout the world. In addition to the health consequences, the impacts on travel behavior have also been sudden and wide ranging. This study describes the drastic changes in human behavior using the analysis of highway volume data as a representation of personal activity and interaction. Same-day traffic volumes for 2019 and 2020 across Florida were analyzed to identify spatial and temporal changes in behavior resulting from the disease or fear of it and statewide directives to limit person-to-person interaction. Compared to similar days in 2019, overall statewide traffic volume dropped …

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Microbial Diversity Drives Carbon Use Efficiency In A Model Soil, Luiz A. Domeignoz-Horta, Grace Pold, Xiao-Jun Allen Liu, Serita D. Frey, Jerry M. Melillo, Kristen M. Deangelis Jul 2020

Microbial Diversity Drives Carbon Use Efficiency In A Model Soil, Luiz A. Domeignoz-Horta, Grace Pold, Xiao-Jun Allen Liu, Serita D. Frey, Jerry M. Melillo, Kristen M. Deangelis

Faculty Publications

Empirical evidence for the response of soil carbon cycling to the combined effects of warming, drought and diversity loss is scarce. Microbial carbon use efficiency (CUE) plays a central role in regulating the flow of carbon through soil, yet how biotic and abiotic factors interact to drive it remains unclear. Here, we combine distinct community inocula (a biotic factor) with different temperature and moisture conditions (abiotic factors) to manipulate microbial diversity and community structure within a model soil. While community composition and diversity are the strongest predictors of CUE, abiotic factors modulated the relationship between diversity and CUE, with CUE …

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Extensive Morphological Variability In Asexually Produced Planktic Foraminifera, Catherine V. Davis, Caitlin M. Livsey, Hannah M. Palmer, Pincelli M. Hull, Ellen Thomas, Tessa M. Hill, Claudia R. Benitez-Nelson Jul 2020

Extensive Morphological Variability In Asexually Produced Planktic Foraminifera, Catherine V. Davis, Caitlin M. Livsey, Hannah M. Palmer, Pincelli M. Hull, Ellen Thomas, Tessa M. Hill, Claudia R. Benitez-Nelson

Faculty Publications

Marine protists are integral to the structure and function of pelagic ecosystems and marine carbon cycling, with rhizarian biomass alone accounting for more than half of all mesozooplankton in the oligotrophic oceans. Yet, understanding how their environment shapes diversity within species and across taxa is limited by a paucity of observations of heritability and life history. Here, we present observations of asexual reproduction, morphologic plasticity, and ontogeny in the planktic foraminifer in laboratory culture. Our results demonstrate that planktic foraminifera reproduce both sexually and asexually and demonstrate extensive phenotypic plasticity in response to nonheritable factors. These two processes fundamentally explain …

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Decomposability Of Soil Organic Matter Over Time: The Soil Incubation Database (Sidb, Version 1.0) And Guidance For Incubation Procedures, Christina Schadel, Jeffrey Beem-Miller, Mina Aziz Rad, Susan E. Crow, Caitlin E. Hicks Pries, Jessica G. Ernakovich, Alison M. Hoyt, Alain Plante, Shane Stoner, Claire C. Treat, Carlos A. Sierra Jul 2020

Decomposability Of Soil Organic Matter Over Time: The Soil Incubation Database (Sidb, Version 1.0) And Guidance For Incubation Procedures, Christina Schadel, Jeffrey Beem-Miller, Mina Aziz Rad, Susan E. Crow, Caitlin E. Hicks Pries, Jessica G. Ernakovich, Alison M. Hoyt, Alain Plante, Shane Stoner, Claire C. Treat, Carlos A. Sierra

Faculty Publications

The magnitude of carbon (C) loss to the atmosphere via microbial decomposition is a function of the amount of C stored in soils, the quality of the organic matter, and physical, chemical, and biological factors that comprise the environment for decomposition. The decomposability of C is commonly assessed by laboratory soil incubation studies that measure greenhouse gases mineralized from soils under controlled conditions. Here, we introduce the Soil Incubation Database (SIDb) version 1.0, a compilation of time series data from incubations, structured into a new, publicly available, open-access database of C flux (carbon dioxide, CO2, or methane, CH4). In addition, …

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Heavy Metals In The Arctic: Distribution And Enrichment Of Five Metals In Alaskan Soils, Clarice R. Perryman, Jochen Wirsing, Kathryn A. Bennett, Owen Brennick, Apryl L. Perry, Nicole Williamson, Jessica G. Ernakovich Jun 2020

Heavy Metals In The Arctic: Distribution And Enrichment Of Five Metals In Alaskan Soils, Clarice R. Perryman, Jochen Wirsing, Kathryn A. Bennett, Owen Brennick, Apryl L. Perry, Nicole Williamson, Jessica G. Ernakovich

Faculty Publications

Metal contamination of food and water resources is a known public health issue in Arctic and sub-Arctic communities due to the proximity of many communities to mining and drilling sites. In addition, permafrost thaw may release heavy metals sequestered in previously frozen soils, potentially contaminating food and water resources by increasing the concentration of metals in freshwater, plants, and wildlife. Here we assess the enrichment of selected heavy metals in Alaskan soils by synthesizing publicly available data of soil metal concentrations. We analyzed data of soil concentrations of arsenic, chromium, mercury, nickel, and lead from over 1,000 samples available through …

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Multi-Attribute Analysis Using Coherency And Ant-Tracking Techniques For Fault And Fracture Detection In La Florida Anticline, Llanos Foothills, Colombia, Ziyad Albesher, James N. Kellogg, Ibraheem Hafiza, Essam Saeid Apr 2020

Multi-Attribute Analysis Using Coherency And Ant-Tracking Techniques For Fault And Fracture Detection In La Florida Anticline, Llanos Foothills, Colombia, Ziyad Albesher, James N. Kellogg, Ibraheem Hafiza, Essam Saeid

Faculty Publications

We present techniques to reduce noise and enhance seismic quality, making possible the first multi-attribute analysis of a 3D seismic volume in the Llanos Foothills (La Florida anticline) of Colombia using coherency and ant-tracking techniques for fault and fracture detection. The results could help reduce risk in models of reservoir fracture porosity and permeability. The dominant fracture strike direction in the studied seismic volume (La Florida anticline) is NE–SW (055 ± 20°), parallel to the structural strike of the adjacent Eastern Cordillera Foothills. The application of the ant-tracking technique also reveals the NE-SW fracture set for the reservoir rocks in …

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Indolic Glucosinolate Pathway Provides Resistance To Mycorrhizal Fungal Colonization In A Non-Host Brassicaceae, Mark A. Anthony, J. L. Celenza, A. Armstrong, Serita D. Frey Apr 2020

Indolic Glucosinolate Pathway Provides Resistance To Mycorrhizal Fungal Colonization In A Non-Host Brassicaceae, Mark A. Anthony, J. L. Celenza, A. Armstrong, Serita D. Frey

Faculty Publications

Most terrestrial plants form mycorrhizas, but a number of agricultural plants, including the Brassicaceae, are non-mycorrhizal. Brassicaceae can still be colonized by arbuscular mycorrhizal fungi (AMF), but species like Arabidopsis thaliana experience growth reductions following AMF colonization at similar magnitude to that of fungal pathogen infections and lack key genes necessary for nutrient exchange. Arabidopsis also produces specific secondary compounds via the modification of tryptophan, including indolic glucosinolates (IGs), which have anti-fungal properties and may therefore be involved in reducing AMF colonization. This study therefore addressed whether the ability to produce IGs facilitates resistance to AMF colonization and growth suppression. …

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Ramped Thermal Analysis For Isolating Biologically Meaningful Soil Organic Matter Fractions With Distinct Residence Times, Jonathan Sanderman, A. Stuart Grandy Apr 2020

Ramped Thermal Analysis For Isolating Biologically Meaningful Soil Organic Matter Fractions With Distinct Residence Times, Jonathan Sanderman, A. Stuart Grandy

Faculty Publications

In this work, we assess whether or not ramped thermal oxidation coupled with determination of the radiocarbon content of the evolved CO2 can be used to isolate distinct thermal fractions of soil organic matter (SOM) along with direct information on the turnover rate of each thermal fraction. Using a 30-year time series of soil samples from a well-characterized agronomic trial, we found that the incorporation of the bomb spike in atmospheric 14CO2 into thermal fractions of increasing resistance to thermal decomposition could be successfully modeled. With increasing temperature, which is proportional to activation energy, the mean residence time of the …

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Genomic Evidence For Formate Metabolism By As The Key To Unlocking Deep Carbon In Lost City Microbial Ecosystems, Julia M. Mcgonigle, Susan Q. Lang, William J. Brazelton Apr 2020

Genomic Evidence For Formate Metabolism By As The Key To Unlocking Deep Carbon In Lost City Microbial Ecosystems, Julia M. Mcgonigle, Susan Q. Lang, William J. Brazelton

Faculty Publications

The Lost City hydrothermal field on the Mid-Atlantic Ridge supports dense microbial life on the lofty calcium carbonate chimney structures. The vent field is fueled by chemical reactions between the ultramafic rock under the chimneys and ambient seawater. These serpentinization reactions provide reducing power (as hydrogen gas) and organic compounds that can serve as microbial food; the most abundant of these are methane and formate. Previous studies have characterized the interior of the chimneys as a single-species biofilm inhabited by the Lost City , but they also indicated that this methanogen is unable to metabolize formate. The new metagenomic results …

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Long-Term Evidence Shows That Crop-Rotation Diversification Increases Agricultural Resilience To Adverse Growing Conditions In North America, Timothy M. Bowles, Maria Mooshammer, Yvonne Socolar, Francisco Calderon, Michel A. Cavigelli, Steve W. Culman, William Deen, Craig F. Drury, Axel Garcia Y Garcia, Amelie C. M. Gaudin, W. Scott Harkcom, R. Michael Lehman, Shannon L. Osborne, G. Philip Robertson, Jonathan Salerno, Marty R. Schmer, Jeffrey Strock, A. Stuart Grandy Mar 2020

Long-Term Evidence Shows That Crop-Rotation Diversification Increases Agricultural Resilience To Adverse Growing Conditions In North America, Timothy M. Bowles, Maria Mooshammer, Yvonne Socolar, Francisco Calderon, Michel A. Cavigelli, Steve W. Culman, William Deen, Craig F. Drury, Axel Garcia Y Garcia, Amelie C. M. Gaudin, W. Scott Harkcom, R. Michael Lehman, Shannon L. Osborne, G. Philip Robertson, Jonathan Salerno, Marty R. Schmer, Jeffrey Strock, A. Stuart Grandy

Faculty Publications

A grand challenge facing humanity is how to produce food for a growing population in the face of a changing climate and environmental degradation. Although empirical evidence remains sparse, management strategies that increase environmental sustainability, such as increasing agroecosystem diversity through crop rotations, may also increase resilience to weather extremes without sacrificing yields. We used multilevel regression analyses of long-term crop yield datasets across a continental precipitation gradient to assess how temporal crop diversification affects maize yields in intensively managed grain systems. More diverse rotations increased maize yields over time and across all growing conditions (28.1% on average), including in …

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Geology Of Nacogdoches, Texas: Texas Academy Of Science March 1, 2020, R. Larell Nielson, Mike Read, Mindy Faulkner, Hannah C. Chambers, Jessica O'Neal Feb 2020

Geology Of Nacogdoches, Texas: Texas Academy Of Science March 1, 2020, R. Larell Nielson, Mike Read, Mindy Faulkner, Hannah C. Chambers, Jessica O'Neal

Faculty Publications

No abstract provided.

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Green Edge Ice Camp Campaigns: Understanding The Processes Controlling The Under-Ice Arctic Phytoplankton Spring Bloom, Philippe Massicotte, Rémi Amiraux, Marie-Pier Amyot, Philippe Archambault, Mathieu Ardyna, Laurent Arnaud, Lise Artigue, Cyril Aubry, Pierre Ayotte, Guislain Bécu, Simon Bélanger, Ronald Benner, Henry C. Bittig, Annick Bricaud, Éric Brossier, Flavienne Bruyant, Et. Al. Jan 2020

Green Edge Ice Camp Campaigns: Understanding The Processes Controlling The Under-Ice Arctic Phytoplankton Spring Bloom, Philippe Massicotte, Rémi Amiraux, Marie-Pier Amyot, Philippe Archambault, Mathieu Ardyna, Laurent Arnaud, Lise Artigue, Cyril Aubry, Pierre Ayotte, Guislain Bécu, Simon Bélanger, Ronald Benner, Henry C. Bittig, Annick Bricaud, Éric Brossier, Flavienne Bruyant, Et. Al.

Faculty Publications

The Green Edge initiative was developed to investigate the processes controlling the primary productivity and fate of organic matter produced during the Arctic phytoplankton spring bloom (PSB) and to determine its role in the ecosystem. Two field campaigns were conducted in 2015 and 2016 at an ice camp located on landfast sea ice southeast of Qikiqtarjuaq Island in Baffin Bay (67.4797∘ N, 63.7895∘ W). During both expeditions, a large suite of physical, chemical and biological variables was measured beneath a consolidated sea-ice cover from the surface to the bottom (at 360 m depth) to better understand the factors driving the …

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Carbon Use Efficiency And Its Temperature Sensitivity Covary In Soil Bacteria, Grace Pold, Luiz A. Domeignoz-Horta, Eric W. Morrison, Serita D. Frey, Seeta A. Sistla, Kristen M. Deangelis Jan 2020

Carbon Use Efficiency And Its Temperature Sensitivity Covary In Soil Bacteria, Grace Pold, Luiz A. Domeignoz-Horta, Eric W. Morrison, Serita D. Frey, Seeta A. Sistla, Kristen M. Deangelis

Faculty Publications

The strategy that microbial decomposers take with respect to using substrate for growth versus maintenance is one essential biological determinant of the propensity of carbon to remain in soil. To quantify the environmental sensitivity of this key physiological trade-off, we characterized the carbon use efficiency (CUE) of 23 soil bacterial isolates across seven phyla at three temperatures and with up to four substrates. Temperature altered CUE in both an isolate-specific manner and a substrate-specific manner. We searched for genes correlated with the temperature sensitivity of CUE on glucose and deemed those functional genes which were similarly correlated with CUE on …

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Pesticide Seed Treatments Containing Neonicotinoids Have Limited Effect On Soil Microbial Community Structure Under Different Tillage Regimes, Jessica E. Mackay, Richard G. Smith, Jessica G. Ernakovich, Lukas T. Bernhardt Dec 2019

Pesticide Seed Treatments Containing Neonicotinoids Have Limited Effect On Soil Microbial Community Structure Under Different Tillage Regimes, Jessica E. Mackay, Richard G. Smith, Jessica G. Ernakovich, Lukas T. Bernhardt

Faculty Publications

Pesticide seed treatments (PST) which contain fungicides and insecticides are commonly used in agriculture; however, little is known about their effect on soil microbial communities and soil health. Neonicotinoids – controversial insecticides which are common in PST – have received criticism due to potential non-target effects. While fungal pathogens need to be moderated, PST have the potential to disturb broader fungal communities which could lead to reduced nutrient cycling and poor soil health. Given the broad use of PST, their effect on soil fungi needs to be studied within the context of other agricultural management practices. For example, tillage regimes …

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Integrating Geochronologic And Instrumental Approaches Across The Bengal Basin, Carol Wilson Nov 2019

Integrating Geochronologic And Instrumental Approaches Across The Bengal Basin, Carol Wilson

Faculty Publications

Constraining time is of critical importance to evaluating the rates and relative contributions of processes driving landscape change in sedimentary basins. The geomorphic character of the field setting guides the application of geochronologic or instrumental tools to this problem, because the viability of methods can be highly influenced by geomorphic attributes. For example, sediment yield and the linked potential for organic preservation may govern the usefulness of radiocarbon dating. Similarly, the rate of sediment transport from source to sink may determine the maturity and/or light exposure of mineral grains arriving in the delta and thus the feasibility of luminescence dating. …

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Grids & Datums, Clifford J. Mugnier Nov 2019

Grids & Datums, Clifford J. Mugnier

Faculty Publications

No abstract provided.

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Short Term Effects Of Hurricane Irma And Cyanobacterial Blooms On Ammonium Cycling Along A Freshwater-Estuarine Continuum In South Florida, Justyna J. Hampel, Mark J. Mccarthy, Megan H. Reed, Silvia E. Newell Oct 2019

Short Term Effects Of Hurricane Irma And Cyanobacterial Blooms On Ammonium Cycling Along A Freshwater-Estuarine Continuum In South Florida, Justyna J. Hampel, Mark J. Mccarthy, Megan H. Reed, Silvia E. Newell

Faculty Publications

Lacustrine and coastal systems are vulnerable to the increasing number and intensity of tropical storms driven by climate change. Strong winds associated with tropical storms can mobilize nutrients in sediments and alter nitrogen and phosphorus cycling, leading to amplification of preexisting conditions, such as eutrophication and cyanobacterial blooms (cyanoHABs). In 2016, Florida declared a State of Emergency within and downstream of Lake Okeechobee (LO) due to toxic cyanobacterial blooms (primarily Microcystis). The blooms originated in LO, but flood control measures released water from LO to the brackish St. Lucie Estuary (SLE). In September 2017, Hurricane Irma traversed the Florida …

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Short- And Intermediate-Range Structure And Dynamics Of Fe-Ni-C Liquid Under Compression, Jianwei Wang Oct 2019

Short- And Intermediate-Range Structure And Dynamics Of Fe-Ni-C Liquid Under Compression, Jianwei Wang

Faculty Publications

Properties of liquid Fe alloys under high-pressure conditions are crucial for understanding the composition, thermal state, and dynamics of Earth's core. Experiments on such liquids, however, are often performed under pressures far below those of the outer core, necessitating long extrapolations of experimental results to core conditions. Such estimates can be complicated by light elements possibly forming pressure-dependent molecular clusters that can significantly affect the physical properties of liquids as core conditions are approached. First-principles molecular dynamics simulations were employed to compute the properties of an Fe-Ni-C liquid with a composition of Fe3.7Ni0.37C at 1673 K and pressures from 0 …

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Short- And Intermediate-Range Structure And Dynamics Of Fe-Ni-C Liquid Under Compression, Jianwei Wang Oct 2019

Short- And Intermediate-Range Structure And Dynamics Of Fe-Ni-C Liquid Under Compression, Jianwei Wang

Faculty Publications

Properties of liquid Fe alloys under high-pressure conditions are crucial for understanding the composition, thermal state, and dynamics of Earth's core. Experiments on such liquids, however, are often performed under pressures far below those of the outer core, necessitating long extrapolations of experimental results to core conditions. Such estimates can be complicated by light elements possibly forming pressure-dependent molecular clusters that can significantly affect the physical properties of liquids as core conditions are approached. First-principles molecular dynamics simulations were employed to compute the properties of an Fe-Ni-C liquid with a composition of Fe3.7Ni0.37C at 1673 K and pressures from 0 …

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Egestion Versus Excretion: A Meta-Analysis Examining Nutrient Release Rates And Ratios Across Freshwater Fauna, Halvor Halvorson, Carla Atkinson Oct 2019

Egestion Versus Excretion: A Meta-Analysis Examining Nutrient Release Rates And Ratios Across Freshwater Fauna, Halvor Halvorson, Carla Atkinson

Faculty Publications

In aquatic settings, animals directly affect ecosystem functions through excretion of dissolved nutrients. However, the comparative role of egestion as an animal-mediated nutrient flux remains understudied. We conducted a literature survey and meta-analysis to directly compare nitrogen (N), phosphorus (P), and N:P of egestion compared to excretion rates and ratios across freshwater animals. Synthesizing 215 datasets across 47 animal species (all primary consumers or omnivores), we show that the total N and P egestion rates exceed inorganic N and P excretion rates but not total N and P excretion rates, and that proportions of P egested compared to excreted depend …

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Nature Of The Crust In The Northern Gulf Of California And Salton Trough, Patricia Persaud Oct 2019

Nature Of The Crust In The Northern Gulf Of California And Salton Trough, Patricia Persaud

Faculty Publications

In the southern Gulf of California, the generation of new oceanic crust has resulted in linear magnetic anomalies and seafloor bathymetry that are characteristic of active seafloor-spreading systems. In the northern Gulf of California and the onshore (southeastern California, USA) Salton Trough region, a thick sedimentary package overlies the crystalline crust, masking its nature, and linear magnetic anomalies are absent. We use potential-field data and a geotherm analysis to constrain the composition of the crust (oceanic or continental) and develop a conceptual model for rifting. Gravity anomalies in the northern Gulf of California and Salton Trough are best fit with …

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Habitability Of The Oceanic Alkaline Serpentinite Subsurface: A Case Study Of The Lost City Hydrothermal Field, Susan Q. Lang, William J. Brazelton Oct 2019

Habitability Of The Oceanic Alkaline Serpentinite Subsurface: A Case Study Of The Lost City Hydrothermal Field, Susan Q. Lang, William J. Brazelton

Faculty Publications

The Lost City hydrothermal field is a dramatic example of the biological potential of serpentinization. Microbial life is prevalent throughout the Lost City chimneys, powered by the hydrogen gas and organic molecules produced by serpentinization and its associated geochemical reactions. Microbial life in the serpentinite subsurface below the Lost City chimneys, however, is unlikely to be as dense or active. The marine serpentinite subsurface poses serious challenges for microbial activity, including low porosities, the combination of stressors of elevated temperature, high pH and a lack of bioavailable ∑CO2. A better understanding of the biological opportunities and challenges in serpentinizing systems …

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Intelligent Identification For Rock-Mineral Microscopic Images Using Ensemble Machine Learning Algorithms, Jonathan Shi Sep 2019

Intelligent Identification For Rock-Mineral Microscopic Images Using Ensemble Machine Learning Algorithms, Jonathan Shi

Faculty Publications

It is significant to identify rock-mineral microscopic images in geological engineering. The task of microscopic mineral image identification, which is often conducted in the lab, is tedious and time-consuming. Deep learning and convolutional neural networks (CNNs) provide a method to analyze mineral microscopic images efficiently and smartly. In this research, the transfer learning model of mineral microscopic images is established based on Inception-v3 architecture. The four mineral image features, including K-feldspar (Kf), perthite (Pe), plagioclase (Pl), and quartz (Qz or Q), are extracted using Inception-v3. Based on the features, the machine learning methods, logistic regression (LR), support vector machine (SVM), …

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Joint Geodetic And Seismic Analysis Of Surface Crevassing Near A Seasonal Glacier-Dammed Lake At Gornergletscher, Switzerland, Louis Garcia, Karen M. Luttrell Sep 2019

Joint Geodetic And Seismic Analysis Of Surface Crevassing Near A Seasonal Glacier-Dammed Lake At Gornergletscher, Switzerland, Louis Garcia, Karen M. Luttrell

Faculty Publications

Seasonal lake Gornersee forms at the confluence of Gornergletscher and Grenzgletscher, Switzerland, and experiences outburst floods annually in midsummer. To study the interplay between lake drainage, glacier movement and crevasse activity, high-frequency seismometers and GPS receivers were deployed in networks near Gornersee during the summer ablation seasons of 2004, 2006 and 2007. We use a Rayleigh wave coherence method to locate 3289, 7939 and 4087 icequakes, respectively, primarily along well-defined surface crevasses. We calculate two-dimensional strains from triads of GPS stations and find mean differential strain rates of similar to 300 x 10(-6) d(-1) with diurnal variations up to 800 …

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Small Soil C Cycle Responses To Three Years Of Cover Crops In Maize Cropping Systems, Anna M. Cates, Matthew D. Ruark, A. Stuart Grandy, Randall D. Jackson Aug 2019

Small Soil C Cycle Responses To Three Years Of Cover Crops In Maize Cropping Systems, Anna M. Cates, Matthew D. Ruark, A. Stuart Grandy, Randall D. Jackson

Faculty Publications

Cover crops are touted for their ability to improve many ecosystem functions in annual cropping systems. In addition to water and nutrient retention, cover crops may influence C cycling by increasing total C inputs to the agroecosystem, stimulating microbial populations, altering main crop residue decomposition rate, or changing litter chemistry over time. We assessed whether annual (rye) or perennial (bluegrass) cover crops in maize cropping systems influenced maize residue decomposition (litterbags) or microbial communities (shotgun metagenomics) in soil and litter, and whether these cover crops had an effect on microbially active pools of C: particulate organic matter (POM) C and …

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Seasonal Variability Of Forces Controlling Sedimentation In The Sundarbans National Forest, Bangladesh, Carol A. Wilson, E. J. Bomer Aug 2019

Seasonal Variability Of Forces Controlling Sedimentation In The Sundarbans National Forest, Bangladesh, Carol A. Wilson, E. J. Bomer

Faculty Publications

Southwest Bangladesh, located on the Ganges-Brahmaputra-Meghna delta, is experiencing the impacts of sea level rise (SLR) due to processes at both the local and global scale. In particular, regional alterations of the hydrodynamic network, due to embankment construction, have drastically altered effective SLR, placing millions of inhabitants at risk of prolonged inundation, and threatening the world's largest continuous mangrove stand, the Sundarbans National Forest (SNF). In order to effectively employ landscape recovery solutions, an understanding of local sediment transport and deposition is critical. This field-based study investigates the sediment dynamics between the mangrove platform and tidal channels of the SNF …

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Agriculture, Ecosystems & Environment, William A. Arigiroff, Donald R. Zak, Rima A. Upchurch, Sydney O. Salley, A. Stuart Grandy Jul 2019

Agriculture, Ecosystems & Environment, William A. Arigiroff, Donald R. Zak, Rima A. Upchurch, Sydney O. Salley, A. Stuart Grandy

Faculty Publications

Fine root litter is a primary source of soil organic matter (SOM), which is a globally important pool of C that is responsive to climate change. We previously established that ~20 years of experimental nitrogen (N) deposition has slowed fine root decay and increased the storage of soil carbon (C; +18%) across a widespread northern hardwood forest ecosystem. However, the microbial mechanisms that have directly slowed fine root decay are unknown. Here, we show that experimental N deposition has decreased the relative abundance of Agaricales fungi (−31%) and increased that of partially ligninolytic Actinobacteria (+24%) on decaying fine roots. Moreover, …

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