Digital Commons Network^™

Winter Climate Change Affects Growing-Season Soil Microbial Biomass And Activity In Northern Hardwood Forests, Jorge Durán, Jennifer L. Morse, Peter M. Groffman, John L. Campbell, Lynn M. Christenson, Charles T. Driscoll, Timothy J. Fahey, Melany C. Fisk, Mryon J. Mitchell, Pamela H. Templer

Environmental Science and Management Faculty Publications and Presentations

Understanding the responses of terrestrial ecosystems to global change remains a major challenge of ecological research. We exploited a natural elevation gradient in a northern hardwood forest to determine how reductions in snow accumulation, expected with climate change, directly affect dynamics of soil winter frost, and indirectly soil microbial biomass and activity during the growing season. Soils from lower elevation plots, which accumulated less snow and experienced more soil temperature variability during the winter (and likely more freeze/thaw events), had less extractable inorganic nitrogen (N), lower rates of microbial N production via potential net N mineralization and nitrification, and higher …

Impact Of Climate Change On Wheat Production In Kentucky, Kathleen Russell, Chad Lee, Rebecca L. Mcculley, David Van Sanford

Plant and Soil Sciences Research Report

Summary:

• From 2002 to 2012, Kentucky winter wheat ranged in value from $52 million to $209 million.
• Climate change and variability have the potential to significantly impact this important economic enterprise within our state.
• This report summarizes the current state of knowledge of the potential of climate change to impact wheat production in Kentucky and surrounding states.

Rapid Fluctuations In Mid-Latitude Siliceous Plankton Production During The Middle Eocene Climatic Optimum (Odp Site 1051, Western North Atlantic), Jakub Witkowski, Steven M. Bohaty, Kirsty M. Edgar, David M. Harwood

ANDRILL Research and Publications

The Middle Eocene Climatic Optimum (MECO; ~ 40 million years ago [Ma]) is one of the most prominent transient global warming events in the Paleogene. Although the event is well documented in geochemical and isotopic proxy records at many locations, the marine biotic response to the MECO remains poorly constrained. We present new high-resolution, quantitative records of siliceous microplankton assemblages from the MECO interval of Ocean Drilling Program (ODP) Site 1051 in the subtropical western North Atlantic Ocean, which are interpreted in the context of published foraminiferal and bulk carbonate stable isotope (δ¹⁸O and δ¹³C) records. …

Burrow Morphology Of The Land Crab Gecarcinus Lateralis And The Ghost Crab Ocypode Quadrata On San Salvador Island, The Bahamas: Comparisons And Palaeoenvironmental Implications, Koji Seike, H. Allen Curran

Geosciences: Faculty Publications

Burrow morphologies of the land crab Gecarcinus lateralis and the ghost crab Ocypode quadrata were investigated on East Beach, San Salvador Island, The Bahamas, with the goals of critical comparison of their morphologies and of clarifying and advancing their palaeoenvironmental usefulness. In comparing land crab burrows to those of the ghost crab, the former are simpler but more variable in overall shape. G. lateralis burrows have a more compressed form in the transverse section of the burrow shaft and possess lower (more horizontal) shaft inclination than those of O. quadrata. In the late Holocene backshore and dune deposits on San …

Stable Isotopic (Δ13C And Δ18O) Signatures Of Biogenic Calcretes Marking Discontinuity Surfaces: A Case Study From Upper Cretaceous Carbonates Of Central Dalmatia And Eastern Istria, Croatia, Mihovil Brlek, Bosiljka Glumac

Geosciences: Faculty Publications

Biogenic calcretes associated with a regional Cretaceous to Paleogene subaerial unconformity and an intraformational composite (polygenic) surface in Upper Cretaceous intra-platform peritidal successions in central Dalmatia and eastern Istria, Croatia (Adriatic-Dinaridic Carbonate Platform), were analyzed for their δ13C and δ18O signatures in order to provide insight into the conditions of subaerial exposure and calcrete development. The distinctly negative δ13C signatures of biogenic calcretes marking the regional subaerial unconformity differ considerably from the δ13C values of the host marine limestones. This indicates carbon isotope exchange of primary marine CaCO3 with CO2 released by root and rhizomicrobial respiration and subsequent precipitation of …

Discontinuity Surfaces In Upper Cretaceous To Paleogene Carbonates Of Central Dalmatia (Croatia): Glossifungites Ichnofacies, Biogenic Calcretes, And Stratigraphic Implications, Mihovil Brlek, Tvrtko Korbar, Adrijan Košir, Bosiljka Glumac, Anita Grizelj, Bojan Otoničar

Geosciences: Faculty Publications

Substrate-controlled ichnofacies and biogenic calcretes represent key features for identification and interpretation of discontinuities in the carbonate rock record, which are of great significance for stratigraphic interpretations and correlations. Intraformational firmground and composite surfaces, as well as a regional Cretaceous to Paleogene (K-Pg) subaerial unconformity, developed in Upper Cretaceous to Paleogene intra-platform peritidal successions in central Dalmatia, Croatia (Adriatic-Dinaridic Carbonate Platform, ADCP), were analyzed for their trace fossil and subaerial exposure features. Thalassinoides (probably T. paradoxicus) box-work burrow systems of the substrate-controlled Glossifungites ichnofacies characterize the two documented firmgrounds and one composite (polygenic) surface. Rhizogenic laminar calcretes developed subsequently inside …

On The Reconstruction Of Plant Photosynthetic And Stress Physiology Across The Triassic-Jurassic Boundary, Matthew Haworth, Angela Gallagher, Elysia Sum, Marlene Hill-Donnelly, Margret Steinthorsdottir, Jennifer Mcelwain

Turkish Journal of Earth Sciences

The Triassic-Jurassic boundary (TJB) coincides with major disruption to the carbon cycle and global warming as the Central Atlantic Magmatic Province developed. This resulted in both marine and terrestrial extinctions, with terrestrial plants thought to experience thermal stress as global temperatures and atmospheric CO_2 levels rose. As plant compression fossils typically only preserve external morphological features, it has not been possible to reconstruct plant paleophysiology in order to elucidate the mechanisms underlying plant stress and extinction. Here we present a new approach allowing us to infer the photosynthetic performance and stress physiology of fossil plants, applied to fossil Ginkgoales across …

A Data Set Of Worldwide Glacier Length Fluctuations, Paul W. Leclercq, Johannes Oerlemans, Hassan J. Basagic, Christina Bushueva, A. J. Cook, Raymond Le Bris

Geology Faculty Publications and Presentations

Glacier fluctuations contribute to variations in sea level and historical glacier length fluctuations are natural indicators of past climate change. To study these subjects, longterm information of glacier change is needed. In this paper we present a data set of global long-term glacier length fluctuations. The data set is a compilation of available information on changes in glacier length worldwide, including both measured and reconstructed glacier length fluctuations. All 471 length series start before 1950 and cover at least four decades. The longest record starts in 1535, but the majority of time series start after 1850. The number of available …

High-Resolution Magnetic Susceptibility Measurements For Investigating Magnetic Mineral Formation During Microbial Mediated Iron Reduction, Estella A. Atekwana, Farag M. Mewafy, Gamal Z. Abdel Aal, D. Dale Werkema, Andre Revil, Lee D. Slater

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Disimilatory iron-reducing bacteria play an important role in the reduction of Fe(hydr)oxides and the production of secondary solid-iron mineral phases that can have magnetic properties. Magnetic susceptibility can therefore play an important role in identifying zones where microbial-mediated iron reduction is occurring. We investigated the magnetic susceptibility variations in a hydrocarbon-contaminated aquifer where methanogenesis and iron reduction are the main biogeochemical processes. Our objectives are to (1) determine the variability of magnetic susceptibility, (2) determine the hydrobiogeochemical controls on the magnetic susceptibility variability, and (3) evaluate the use of magnetic susceptibility as a viable technique for identifying zones where the …

A Review Of The Hyporheic Zone, Stream Restoration, And Means To Enhance Denitrification, Leanne Merill, David J. Tonjes

Technology & Society Faculty Publications

The hyporheic zone is the subsurface area below and adjacent to a stream where groundwater mixes with stream water, through vertical, lateral, and longitudinal flows. The hyporheic zone connects the stream to uplands and other terrestrial environments. It is a zone of distinct faunal communities, high biological diversity and ecological complexity, and is the site of chemical processing and transformations of ground- and stream waters. The hyporheic zone is important to the overall ecosystem ecology of the stream, and it can influence stream water chemistry. Flows, reactions, and biota in the hyporheic zone are heterogeneous and patchy, making it difficult …

Comparison Of Herbicide Systems For Dark Fire-Cured Tobacco, William A. Bailey, Tim Lax, Bobby Hill

Plant and Soil Sciences Research Report

Field experiments were conducted at Murray, KY in 2005, 2006, and 2007 to compare dark tobacco tolerance and weed control from various herbicide systems applied prior to transplanting. Herbicide treatments included sulfentrazone at 0.38 lb ai/A (12 oz/A Spartan 4F) applied pretransplant (PT), clomazone at 1 lb ai/A PT (2.67 pt/A Command 3ME), sulfentrazone at 0.38 lb ai/A plus clomazone at 1 lb ai/A PT, pendimethalin at 1.48 lb ai/A (3.6 pt/A Prowl 3.3EC) applied pretransplant incorporated (PTI), pendimethalin at 1.48 lb ai/A PTI followed by sulfentrazone at 0.38 lb ai/A PT, pebulate at 4 lb ai/A PTI (2.67 qt/A …

The Fluvial Sequence Of A Latest Changhsingian, Pre-Pt Extinction River Complex, Eastern Cape Province, South Africa, Tara Chizinski

Honors Theses

The Permian–Triassic mass extinction, dated between 251.941 ± 0.037 and 251.880 ± 0.0371 Ma, is well documented in the marine record, but details of the event on land are still ambiguous and widely debated within the scientific community. This project focuses on the stratigraphic record leading up to the PT boundary at one of the critical sections in the Karoo Basin of South Africa, Wapadsberg Pass. A transition in river styles is reported to have occurred across the landscape from meandering Permian sandstone-dominated channels to Triassic braided complexes. This transition can be recorded by architectural elements, which reflect sensitive variations …

Phytoplankton And Nutrient Dynamics In A Tidally Dominated Eutrophic Estuary: Daily Variability And Controls On Bloom Formation, Ryan E. Morse, Margaret R. Mulholland, Todd A. Egerton, Harold G. Marshall

OES Faculty Publications

To better understand nutrient dynamics and factors that promote the initiation of algal blooms, the Lafayette River, a tidal subestuary of Chesapeake Bay that experiences seasonal algal blooms, was sampled daily for a period of 54 d in the fall of 2005. Three phytoplankton blooms (chl a concentrations exceeding twice the average of monthly measurements from 2000 to 2009) occurred during this period: a mixed bloom of Akashiwo sanguinea and Gymnodinium sp., a monospecific Skeletonema costatum bloom, and a monospecific Gymnodinium sp. bloom. Over the sampling period, nutrient concentrations increased following precipitation events and were elevated between bloom periods but …

The Great 2012 Arctic Ocean Summer Cyclone Enhanced Biological Productivity On The Shelves, Jinlun Zhang, Carin Ashjian, Robert Campbell, Victoria Hill, Yvette H. Spitz, Michael Steele

OES Faculty Publications

A coupled biophysical model is used to examine the impact of the great Arctic cyclone of early August 2012 on the marine planktonic ecosystem in the Pacific sector of the Arctic Ocean (PSA). Model results indicate that the cyclone influences the marine planktonic ecosystem by enhancing productivity on the shelves of the Chukchi, East Siberian, and Laptev seas during the storm. Although the cyclone's passage in the PSA lasted only a few days, the simulated biological effects on the shelves last 1 month or longer. At some locations on the shelves, primary productivity (PP) increases by up to 90% and …

The Impact Of Changing Surface Ocean Conditions On The Dissolution Of Aerosol Iron, Matthew P. Fishwick, Peter N. Sedwick, Maeve C. Lohan, Paul J. Worsfold, Kristen N. Buck, Thomas M. Church, Simon J. Ussher

OES Faculty Publications

The proportion of aerosol iron (Fe) that dissolves in seawater varies greatly and is dependent on aerosol composition and the physicochemical conditions of seawater, which may change depending on location or be altered by global environmental change. Aerosol and surface seawater samples were collected in the Sargasso Sea and used to investigate the impact of these changing conditions on aerosol Fe dissolution in seawater. Our data show that seawater temperature, pH, and oxygen concentration, within the range of current and projected future values, had no significant effect on the dissolution of aerosol Fe. However, the source and composition of aerosols …

Boron Nutrition Of Burley And Dark Tobacco, Laura Ann Frakes Mitchell

Theses and Dissertations--Plant and Soil Sciences

The incidences of suspected Boron (B) deficiency have increased recently in Kentucky tobacco fields, potentially due to recent changes in management practices. The symptoms observed in the field include; hollow stalk, stunted growth, deformed or no bud formation, small slits on the lower leaf midrib and uncontrollable breaking of the midrib approximately two inches from the stalk. B is a micronutrient tobacco needs in minute amounts, however excessive additions of B could cause toxicity. The objectives of this work were to 1) establish critical points for B sufficiency, 2) describe and define B deficiency and toxicity symptoms and 3) develop …

Quantifying Nutrient Cycling And Fate Within An Abandoned Feedlot And Adjacent Wetlands, Prosper Prosper Gbolo

Theses and Dissertations

Feedlot operations over the years have increased revenue and boosted economies of states and countries, but these operations have resulted in elevated concentrations of nutrients in soils, surface water, and groundwater. Feedlot operations generate large quantities of manure and other waste, which when not managed properly can result in environmental problems.

It is hypothesized that nitrogen can cause a short-term contamination of soils and groundwater beneath abandoned feedlots, but phosphorus can cause both short- and long term contamination, especially in well-drained carbonate and iron-rich soils associated with Concentrated Animal Feeding Operations. It is also hypothesized that a spectral vegetation index …

Carbon And Nitrogen Isotope Analysis Of Archaeological Faunal Material From Dutchess Quarry Caves, Ny, Jessica Zuhlke

Legacy Theses & Dissertations (2009 - 2024)

The purpose of this study was to do an isotopic analysis to determine the carbon and nitrogen isotope concentrations of archaeological faunal material found in the Dutchess Quarry Caves in Orange County, NY. These isotope values were then used to compare the taxa from which the samples were taken to determine if and how trophic relationships were formed. The main focus of this comparison spotlighted a sample from a human femur; to establish the human's position trophically with the other large and small mammal samples collected. The human had been previously radiocarbon dated to have lived between 2877 and 3180 …

Convergence Of Dune Topography Among Multiple Barrier Island Morphologies, Jackie Ann Monge

Theses and Dissertations--Geography

Wave-dominated and mixed tidal and wave energy barrier islands are assumed to have characteristic dune topographies that link to their macroscale form. However, there has been no systematic attempt to describe the linkage between barrier island macroscale form and dune topography. The goal of this thesis was to investigate how dune topographies correspond to a number of barrier island morphologies found along the southeastern U.S. Atlantic coast. Macroscale process-form variables were used to classify 77 islands into seven morphologic clusters. Islands from each cluster were selected and sites characteristic of the range of dune topographies within islands were characterized using …

Temporal Evolution Of The Water Characteristics In The Bays Along The Eastern Coast Of The Aegean Sea: Saros, İzmir, And Gökova Bays, Canan Eronat, Erdem Sayin

Turkish Journal of Earth Sciences

The seasonal and interannual variability of the local hydrography in 3 bays (Saros, İzmir, and Gökova bays) along the eastern coast of the Aegean Sea are investigated using data sets collected from 1991 to 2010. The data cover the last major deep-water formation episodes and the Eastern Mediterranean Transient (EMT) relaxation period. Aegean Sea hydrology and water mass characteristics influence the water properties of the bays. The data suggest that Saros Bay (North Aegean Sea), İzmir Bay (Central Aegean Sea), and Gökova Bay (South Aegean Sea) have different physical processes and water characteristics. They have their own dynamics independent from …

Early Pleistocene Freshwater Communities And Rodents From The Pasinler Basin (Erzurum Province, North-Eastern Turkey), Davit Vasilyan, Simon Schneider, Memet Sali̇h Bayraktutan, Şevket Şen

Turkish Journal of Earth Sciences

An Early Pleistocene lacustrine faunal assemblage from Pasinler (Erzurum Province, north-eastern Turkey) is described, which encompasses 13 mollusc, 5 fish, 2 amphibian, 1 reptile, and 1 mammal species. The autochthonous freshwater mollusc fauna indicates shallow stagnant waters and a fine-sandy to muddy lake bottom, grown with submersed plants. The fish community (Leuciscus sp., Rutilus sp., Chondrostoma sp., Leuciscinae sp. 1 and 2, and Capoeta sp.) and autochthonous herpetofauna (Latonia sp. and Natrix sp.) provide evidence of a well-oxygenised palaeolake with rich periphyton and partially rocky to gravelly bottom. Moreover, the presence of the terrestrial snail Caspicyclotus cf. akramowsii, the peri- …

Adverse Outcome Pathway And Risks Of Anticoagulant Rodenticides To Predatory Wildlife, Barnett A. Rattner, Rebecca S. Lazarus, John E. Elliott, Richard F. Shore, Nico Van Den Brink

United States Geological Survey: Staff Publications

Despite a long history of successful use, routine application of some anticoagulant rodenticides (ARs) may be at a crossroad due to new regulatory guidelines intended to mitigate risk. An adverse outcome pathway for ARs was developed to identify information gaps and end points to assess the effectiveness of regulations. This framework describes chemical properties of ARs, established macromolecular interactions by inhibition of vitamin K epoxide reductase, cellular responses including altered clotting factor processing and coagulopathy, organ level effects such as hemorrhage, organism responses with linkages to reduced fitness and mortality, and potential consequences to predator populations. Risk assessments have led …

Production And Transformation Of Dissolved Neutral Sugars And Amino Acids By Bacteria In Seawater, L. Jørgensen, O. J. Lechtenfeld, Ronald Benner, M. Middleboe, C. A. Stedmon

Faculty Publications

Dissolved organic matter (DOM) in the ocean consists of a heterogeneous mixture of molecules, most of which are of unknown origin. Neutral sugars and amino acids are among the few recognizable biomolecules in DOM, and the molecular composition of these biomolecules is shaped primarily by biological production and degradation processes. This study provides insight into the bioavailability of biomolecules as well as the chemical composition of DOM produced by bacteria. The molecular compositions of combined neutral sugars and amino acids were investigated in DOM produced by bacteria and in DOM remaining after 32 days of bacterial degradation. Results from bioassay …

A Quantitative Analysis Of White-Tailed Deer Harvest Across States And Counties, Rebecca Lynne Cain

Theses and Dissertations

White-tailed deer (Odocoileus virginianus) have gone from locally extirpated to overabundant in many areas in the United States since the early 1900s. Ecosystems with chronically overabundant populations experience many disastrous effects resulting from the selective browsing behavior of deer. White-tailed deer are managed at the state level resulting in different management strategies, harvest data collection, and deer management goals between states. However recreational hunting is the primary tool used by wildlife agencies to control population growth. As such, it is beneficial to understand the influence each regulatory variable has on white-tailed deer harvest.

For this research, I compiled historical harvest …

Biomineralization Of Carbonates In Modern Microbial Sediments And Its Implications For Co₂ Sequestration, Varun Gnanaprian Paul

Doctoral Dissertations

"Several bacterial species influence carbonate mineral precipitation by modifying pH, alkalinity, Ca²⁺ activity and by providing nucleation sites for mineralization. Two studies have been undertaken to explore microbial influence in the mineralization of carbonates. In the first study, the ability of sulfate-reducing bacteria (SRB) to induce carbonate mineralization was investigated as a means to enhance mineral sequestration of CO₂. Sulfate-reducing bacteria enriched from hypersaline Storr's Lake, The Bahamas; Lake Estancia, New Mexico; and Great Salt Plains Lake, Oklahoma, were tested in reactors under varying CO₂ concentrations. Carbonate mineral precipitation was achieved only in reactors with Lake Estancia SRB community and …

Searching For Cold-Adapted Microorganisms In The Underground Glacier Of Scarisoara Ice Cave, Romania, Alexandra Maria Hillebrand-Voiculescu, Corina Itcus, Ioan Ardelean, Denisa Pascu, Aurel Persoiu, Andreea Rusu, Traian Brad, Elena Popa, Bogdan P. Onac, Christina Purcarea

School of Geosciences Faculty and Staff Publications

Scarisoara Ice Cave (Romania) hosts one of world’s largest and oldest underground glacier. While no studies were carried out on the existence of microorganisms in this cave’s ice block, our interest is to investigate the presence of microorganisms and their chronological distribution in the cave’s subterranean ice in relationship with past climatic changes. Samples were collected from ice layers of different age (from present to ~900 cal. yrs. BP), and the diversity of embedded microbial communities was assessed by classical cultivation and molecular techniques. The microorganisms from icesediments were cultivated at 4 °C and 15 °C, in the presence and …

City Of Tampa Urban Forest Management, Monitoring And Policy, Shawn M. Landry, Robert J. Northrop, Michael G. Andreu, Kathy Beck

School of Geosciences Faculty and Staff Publications

No abstract provided.

Analysis Of Vesicular Porosity In Soils Using High-Resolution X-Ray Computed Tomograpy, Judith K. Turk, Robert C. Graham

Conservation and Survey Division: Faculty and Staff Publications

Vesicular horizons are common at the surface of arid and semiarid soils and play a critical role in regulating infiltration. Most methods for examining pore morphology in the vesicular horizon involve physical sectioning of the sample and individual measurement of pores, which is time-consuming and provides an incomplete view of the pores. The objectives of this study were to (i) develop methods for the classification and characterization of pores in the vesicular horizon using high resolution X-ray computed tomography (HRXCT) and (ii) use these methods to examine the distribution of pores within vesic-ular peds. Three intact peds were scanned by …

Benthic And Pelagic Pathways Of Methylmercury Bioaccumulation In Estuarine Food Webs Of The Northeast United States, Celia Y. Chen, Mark E. Borsuk, Deenie M. Bugge, Terill Hollweg

Dartmouth Scholarship

Methylmercury (MeHg) is a contaminant of global concern that bioaccumulates and bioamagnifies in marine food webs. Lower trophic level fauna are important conduits of MeHg from sediment and water to estuarine and coastal fish harvested for human consumption. However, the sources and pathways of MeHg to these coastal fisheries are poorly known particularly the potential for transfer of MeHg from the sediment to biotic compartments. Across a broad gradient of human land impacts, we analyzed MeHg concentrations in food webs at ten estuarine sites in the Northeast US (from the Hackensack Meadowlands, NJ to the Gulf of Maine). MeHg concentrations …

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

Chemistry & Biochemistry Faculty Publications

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