Digital Commons Network^™

Northern Eurasia Future Initiative (Nefi): Facing The Challenges And Pathways Of Global Change In The Twenty-First Century, Pavel Ya. Groisman, Herman Shugart, David Kicklighter, Geoffrey Henebry, Nadezhda Tchebakova, Shamil Maksyutov, Erwan Monier, Garik Gutman, Sergey Gulev, Jiaguo Qi, Alexander Prishchepov, Elena Kukavskaya, Boris Porfiriev, Alexander I. Shiklomanov, Tatiana Loboda, Nikolay Shiklomanov, Son Nghiem, Kathleen Bergen, Jana Albrechtova, Jiquan Chen, Maria Shahgedanova, Anatoly Shvidenko, Nina Speranskaya, Amber Soja

Faculty Publications

During the past several decades, the Earth system has changed significantly, especially across Northern Eurasia. Changes in the socio-economic conditions of the larger countries in the region have also resulted in a variety of regional environmental changes that can have global consequences. The Northern Eurasia Future Initiative (NEFI) has been designed as an essential continuation of the Northern Eurasia Earth Science Partnership Initiative (NEESPI), which was launched in 2004. NEESPI sought to elucidate all aspects of ongoing environmental change, to inform societies and, thus, to better prepare societies for future developments. A key principle of NEFI is that these developments …

No Consistent Evidence For Advancing Or Delaying Trends In Spring Phenology On The Tibetan Plateau, Xufeng Wang, Jingfeng Xiao, Xin Li, Guodong Cheng, Mingguo Ma, Tao Che, Shaoying Wang, Jinkui Wu

Faculty Publications

Vegetation phenology is a sensitive indicator of climate change and has significant effects on the exchange of carbon, water, and energy between the terrestrial biosphere and the atmosphere. The Tibetan Plateau, the Earth's “third pole,” is a unique region for studying the long‐term trends in vegetation phenology in response to climate change because of the sensitivity of its alpine ecosystems to climate and its low‐level human disturbance. There has been a debate whether the trends in spring phenology over the Tibetan Plateau have been continuously advancing over the last two to three decades. In this study, we examine the trends …

Using Milk Urea Nitrogen To Calculate Urine And Urinary Nitrogen Output, Peter S. Erickson

Faculty Publications

No abstract provided.

Utilizing Undf In Dairy Cow Diets: A New Way Of Looking At Forage Fiber, Peter S. Erickson

Faculty Publications

No abstract provided.

Short Communication: Massive Erosion In Monsoonal Central India Linked To Late Holocene Land Cover Degradation, Liviu Giosan, Camilo Ponton, Muhammed Usman, Jerzy Glusztajn, Dorian Q. Fuller, Valier Galy, Negar Haghipour, Joel E. Johnson, Cameron Mcintyre, Lukas Wacker, Timothy I. Eglinton

Faculty Publications

Soil erosion plays a crucial role in transferring sediment and carbon from land to sea, yet little is known about the rhythm and rates of soil erosion prior to the most recent few centuries. Here we reconstruct a Holocene erosional history from central India, as integrated by the Godavari River in a sediment core from the Bay of Bengal. We quantify terrigenous fluxes, fingerprint sources for the lithogenic fraction and assess the age of the exported terrigenous carbon. Taken together, our data show that the monsoon decline in the late Holocene significantly increased soil erosion and the age of exported …

Individual Differences In Eeg Correlates Of Recognition Memory Due To Dat Polymorphisms, Paolo Medrano, Erika Nyhus, Andrew Smolen, Tim Curran, Robert S. Ross

Faculty Publications

Introduction

Although previous research suggests that genetic variation in dopaminergic genes may affect recognition memory, the role dopamine transporter expression may have on the behavioral and EEG correlates of recognition memory has not been well established.

Objectives

The study aims to reveal how individual differences in dopaminergic functioning due to genetic variations in the dopamine transporter gene influences behavioral and EEG correlates of recognition memory.

Methods

Fifty‐eight participants performed an item recognition task. Participants were asked to retrieve 200 previously presented words while brain activity was recorded with EEG. Regions of interest were established in scalp locations associated with recognition …

Aquatic Nitrate Retention At River Network Scales Across Flow Conditions Determined Using Nested In Situ Sensors, Wilfred Wollheim, Gopala K. Mulukutla, C. Cook, R. O. Carey

Faculty Publications

Nonpoint pollution sources are strongly influenced by hydrology and are therefore sensitive to climate variability. Some pollutants entering aquatic ecosystems, e.g., nitrate, can be mitigated by in‐stream processes during transport through river networks. Whole river network nitrate retention is difficult to quantify with observations. High frequency, in situ nitrate sensors, deployed in nested locations within a single watershed, can improve estimates of both nonpoint inputs and aquatic retention at river network scales. We deployed a nested sensor network and associated sampling in the urbanizing Oyster River watershed in coastal New Hampshire, USA, to quantify storm event‐scale loading and retention at …

The Structure Of Coronene Cluster Ions Inferred From H2 Uptake In The Gas Phase, Marcelo Goulart, Martin Kuhn, Bilal Rasul, Johannes Postler, Michael Gatchell, Henning Zettergren, Paul Scheier, Olof Echt

Faculty Publications

Mass spectra of helium nanodroplets doped with H2 and coronene feature anomalies in the ion abundance that reveal anomalies in the energetics of adsorption sites. The coronene monomer ion strongly adsorbs up to n = 38 H2 molecules indicating a commensurate solvation shell that preserves the D6h symmetry of the substrate. No such feature is seen in the abundance of the coronene dimer through tetramer complexed with H2; this observation rules out a vertical columnar structure. Instead we see evidence for a columnar structure in which adjacent coronenes are displaced in parallel, forming terraces that offer additional strong adsorption sites. …

Nitrification Increases Nitrogen Export From A Tropical River Network, Lauren E. Koenig, Chao Song, Wilfred M. Wollheim, Janine Ruegg, William H. Mcdowell

Faculty Publications

Scaling aquatic ecosystem processes like nutrient removal is critical for assessing the importance of streams and rivers to watershed nutrient export. We used pulse NH4+ enrichment experiments and measured net NH4+ uptake in 7 streams throughout a mountainous tropical river network in Puerto Rico to assess spatial variability in NH4+ uptake and to infer the physical, chemical, and biological characteristics that most influence its variation. Across 14 experiments, NH4+ uptake velocity (vf) ranged from 0.3 to 8.5 (mean = 2.7) mm/min and was positively related to algal biomass standing stock, measured as chlorophyll a. On average, 49% of experimentally added …

Soil Carbon Cycling Proxies: Understanding Their Critical Role In Predicting Climate Change Feedbacks, Vanessa L. Bailey, Ben Bond-Lamberty, Kristen M. Deangelis, A. Stuart Grandy, Christine V. Hawkes, Kate Heckman, Kate Lajtha, Richard P. Phillips, Benjamin N. Sulman, Katherine E. O. Todd-Brown, Matthew D. Wallenstein

Faculty Publications

The complexity of processes and interactions that drive soil C dynamics necessitate the use of proxy variables to represent soil characteristics that cannot be directly measured (correlative proxies), or that aggregate information about multiple soil characteristics into one variable (integrative proxies). These proxies have proven useful for understanding the soil C cycle, which is highly variable in both space and time, and are now being used to make predictions of the fate and persistence of C under future climate scenarios. However, the C pools and processes that proxies represent must be thoughtfully considered in order to minimize uncertainties in empirical …

Fungal Community Homogenization, Shift In Dominant Trophic Guild, And Appearance Of Novel Taxa With Biotic Invasion, Mark A. Anthony, Serita D. Frey, Kristina A. Stinson

Faculty Publications

Invasion by non-native plants may fundamentally restructure the soil fungal community. The invasive plant, Alliaria petiolata, produces secondary compounds suppressive to mycorrhizal fungi and may therefore be expected to have generally negative effects on other components of the fungal community. Here, we compared fungal biomass, diversity, community composition, and the relative abundance of fungal trophic guilds, along with edaphic properties of soils collected from uninvaded and invaded plots across six temperate forests. Invaded plots were differentiated from uninvaded plots by lower variation in fungal community composition (beta diversity) and soil properties, higher fungal richness and community evenness (alpha diversity), and …

Are Northeastern U.S. Forests Vulnerable To Extreme Drought?, Adam P. Coble, Matthew A. Vadeboncoeur, Z. Carter Berry, Katie A. Jennings, Cameron D. Mcintire, John L. Campbell, Lindsey E. Rustad, Pamela H. Templer, Heidi Asbjornsen

Faculty Publications

In the Northeastern U.S., drought is expected to increase in frequency over the next century, and therefore, the responses of trees to drought are important to understand. There is recent debate about whether land-use change or moisture availability is the primary driver of changes in forest species composition in this region. Some argue that fire suppression from the early twentieth century to present has resulted in an increase in shade-tolerant and pyrophobic tree species that are drought intolerant, while others suggest precipitation variability as a major driver of species composition. From this debate, an emerging hypothesis is that mesophication and …

Blood Pressure And Cardiovascular Health Has Relationship With Age In Adults During Adulthood, Allyson K. Getty, Jessica M. Lenzo, Tia R. Wisdo, Jovann E. Oakman, Christina M. Cromwell, Jessica A. Hill, Lauren N. Chavis, Deborah L. Feairheller

Faculty Publications

Efforts to combat cardiovascular disease (CVD) have proven effective, especially in the population aged 55-74 years. However, less research has been conducted in younger populations to determine at what age CVD risk develops. The purpose of this study is to compare cardiovascular health markers in adults, specifically CVD risk between younger adults aged 18-22 and a slightly older group of adults in middle adulthood aged 23-54. Cardiovascular health measures were collected from a group of adults; 13 younger adults (20.2±0.9 yrs) and 10 adults in middle adulthood (42.9±10.1 yrs). All participants were free of CVD and diabetes, taking no cholesterol …

Stable Isotopes And Radiocarbon Assess Variable Importance Of Plants And Fungi In Diets Of Arctic Ground Squirrels, Erik A. Hobbie, Julee Shamhart, Michael Sheriff, Andrew P. Ouimette, Matt Trappe, Edward A. G. Schuur, John E. Hobbie, Rudy Boonstra, Brian M. Barnes

Faculty Publications

Arctic ground squirrels (Urocitellus parryii) rely primarily on dietary protein derived from plants to fuel gluconeogenesis during hibernation, yet fungal sporocarps may be an important, yet overlooked, protein source. Fungivory levels depend on sporocarp productivity, which varies with the dominant plant species and is higher on acidic than on non-acidic soils. To test whether these factors altered fungal consumption, we used stable isotopes to investigate arctic ground squirrel diets at two sites in northern Alaska, Toolik (primarily moist acidic tundra) and Atigun (primarily moist non-acidic tundra). Radiocarbon estimates can also indicate fungivory levels because ectomycorrhizal fungi assimilate soil-derived organic nitrogen …

Core Handling And Processing For The Wais Divide Ice-Core Project, Joseph M. Souney, Mark S. Twickler, Geoffrey M. Hargreaves, Brian M. Bencivengo, Matthew J. Kippenhan, Jay A. Johnson, Eric D. Cravens, Peter D. Neff, Richard M. Nunn, Anais J. Orsi, Trevor J. Popp, John F. Rhoades, Bruce H. Vaughn, Donald E. Voigt, Gifford J. Wong, Kendrick C. Taylor

Faculty Publications

On 1 December 2011 the West Antarctic Ice Sheet (WAIS) Divide ice-core project reached its final depth of 3405 m. The WAIS Divide ice core is not only the longest US ice core to date, but is also the highest-quality deep ice core, including ice from the brittle ice zone, that the US has ever recovered. The methods used at WAIS Divide to handle and log the drilled ice, the procedures used to safely retrograde the ice back to the US National Ice Core Laboratory (NICL) and the methods used to process and sample the ice at the NICL are …

Changes In Substrate Availability Drive Carbon Cycle Response To Chronic Warming, Grace Pold, A. Stuart Grandy, Jerry M. Melillo, Kristen M. Deangelis

Faculty Publications

As earth's climate continues to warm, it is important to understand how the capacity of terrestrial ecosystems to retain carbon (C) will be affected. We combined measurements of microbial activity with the concentration, quality, and physical accessibility of soil carbon to microorganisms to evaluate the mechanisms by which more than two decades of experimental warming has altered the carbon cycle in a Northeast US temperate deciduous forest. We found that concentrations of soil organic matter were reduced in both the organic and mineral soil horizons. The molecular composition of the carbon was altered in the mineral soil with significant reductions …

Hegel's Revival In Analytic Philosophy, Willem A. Devries

Faculty Publications

Analytic philosophy is rediscovering Hegel. This essay examines a particularly strong thread of new analytic Hegelianism, sometimes called ‘Pittsburgh Hegelianism’, which began with the work of Wilfrid Sellars. In trying to bring Anglo-American philosophy from its empiricist phase into a more sophisticated, corrected Kantianism, Sellars moved in substantially Hegelian directions. Sellars’ work has been extended, and revised by his Pittsburgh colleagues John McDowell and Robert B. Brandom. The sociality and historicity of reason, the proper treatment of space and time, conceptual holism, inferentialism, the reality of conceptual structure, the structure of experience, and the nature of normativity are the central …

Rock Magnetic And Geochemical Evidence For Authigenic Magnetite Formation Via Iron Reduction In Coal-Bearing Sediments Offshore Shimokita Peninsula, Japan (Iodp Site C0020), Stephen C. Phillips, Joel E. Johnson, William C. Clyde, Jacob B. Setera, Daniel P. Maxbauer, Silke Severmann, Natascha Riedinger

Faculty Publications

Sediments recovered at Integrated Ocean Drilling Program (IODP) Site C0020, in a fore‐arc basin offshore Shimokita Peninsula, Japan, include numerous coal beds (0.3–7 m thick) that are associated with a transition from a terrestrial to marine depositional environment. Within the primary coal‐bearing unit (∼2 km depth below seafloor) there are sharp increases in magnetic susceptibility in close proximity to the coal beds, superimposed on a background of consistently low magnetic susceptibility throughout the remainder of the recovered stratigraphic sequence. We investigate the source of the magnetic susceptibility variability and characterize the dominant magnetic assemblage throughout the entire cored record, using …

Long-Term Carbon And Nitrogen Dynamics At Spruce Revealed Through Stable Isotopes In Peat Profiles, Erik A. Hobbie, Janet Chen, Paul J. Hanson, Colleen M. Iversen, Karis J. Mcfarlane, Nathan R. Thorp, Kirsten S. Hofmockel

Faculty Publications

Peatlands encode information about past vegetation dynamics, climate, and microbial processes. Here, we used δ15N and δ13C patterns from 16 peat profiles to deduce how the biogeochemistry of the Marcell S1 forested bog in northern Minnesota responded to environmental and vegetation change over the past  ∼ 10000 years. In multiple regression analyses, δ15N and δ13C correlated strongly with depth, plot location, C∕N, %N, and each other. Correlations with %N, %C, C∕N, and the other isotope accounted for 80% of variance for δ15N and 38% of variance for δ13C, reflecting N and C losses. In contrast, correlations with depth and topography …

Evaluating Consistency Of Snow Water Equivalent Retrievals From Passive Microwave Sensors Over The North Central U. S.: Ssm/I Vs. Ssmis And Amsr-E Vs. Amsr2, Eunsang Cho, Samuel E. Tuttle, Jennifer M. Jacobs

Faculty Publications

For four decades, satellite-based passive microwave sensors have provided valuable snow water equivalent (SWE) monitoring at a global scale. Before continuous long-term SWE records can be used for scientific or applied purposes, consistency of SWE measurements among different sensors is required. SWE retrievals from two passive sensors currently operating, the Special Sensor Microwave Imager Sounder (SSMIS) and the Advanced Microwave Scanning Radiometer 2 (AMSR2), have not been fully evaluated in comparison to each other and previous instruments. Here, we evaluated consistency between the Special Sensor Microwave/Imager (SSM/I) onboard the F13 Defense Meteorological Satellite Program (DMSP) and SSMIS onboard the F17 …

Population Pressure And Global Markets Drive A Decade Of Forest Cover Change In Africa's Albertine Rift, Sadie J. Ryan, Michael W. Palace, Joel N. Hartter, Jeremy E. Diem, Colin A. Chapman, J. Southworth

Faculty Publications

Africa's Albertine Rift region faces a juxtaposition of rapid human population growth and protected areas, making it one of the world's most vulnerable biodiversity hotspots. Using satellite-derived estimates of forest cover change, we examined national socioeconomic, demographic, agricultural production, and local demographic and geographic variables, to assess multilevel forces driving local forest cover loss and gain outside protected areas during the first decade of this century. Because the processes that drive forest cover loss and gain are expected to be different, and both are of interest, we constructed models of significant change in each direction. Although rates of forest cover …

Adherence To Exercise Prescription And Improvements In The Clinical And Vascular Health Of African Americans, Dianne M. Babbitt, Amanda M. Perkins, Keith M. Diaz, Deborah L. Feairheller, Kathleen M. Sturgeon, Praveen Veerabhadrappa, Sheara T. Williamson, Jan Kretzschmar, Chenyi Ling, Hojun Lee, Heather Grim, Michael D. Brown

Faculty Publications

Improvements in indices of vascular health and endothelial function have been inversely associated with hypertension, a risk factor for cardiovascular disease (e.g., myocardial infarction, stroke, and heart failure), renal failure, and mortality. Aerobic exercise training (AEXT) has been positively associated with improvements in clinical health values, as well as vascular health biomarkers, and endothelial function. The purpose of this study was to evaluate whether measures of exercise adherence were related to clinical outcome measures and indices of vascular health subsequent to a 6-month AEXT intervention in a middle-to-older aged African American cohort. Following dietary stabilization, sedentary, apparently healthy, African American …

Submarine Deposits From Pumiceous Pyroclastic Density Currents Traveling Over Water: An Outstanding Example From Offshore Montserrat (Iodp 340), M. Jutzeler, M. Manga, J. D. L. White, P. J. Talling, Alexander A. Prusevich, S. F. L. Watt, M. Cassidy, R. N. Taylor, A. Le Friant, O. Ishizuka

Faculty Publications

Pyroclastic density currents have been observed to both enter the sea, and to travel over water for tens of kilometers. Here, we identified a 1.2-m-thick, stratified pumice lapilli-ash cored at Site U1396 offshore Montserrat (Integrated Ocean Drilling Program [IODP] Expedition 340) as being the first deposit to provide evidence that it was formed by submarine deposition from pumice-rich pyroclastic density currents that traveled above the water surface. The age of the submarine deposit is ca. 4 Ma, and its magma source is similar to those for much younger Soufrière Hills deposits, indicating that the island experienced large-magnitude, subaerial caldera-forming explosive …

Cover Crop Root Contributions To Soil Carbon In A No-Till Corn Bioenergy Cropping System, Emily E. Austin, Kyle Wickings, Marshall D. Mcdaniel, G. Philip Robertson, A. Stuart Grandy

Faculty Publications

Crop residues are potential biofuel feedstocks, but residue removal may reduce soil carbon (C). The inclusion of a cover crop in a corn bioenergy system could provide additional biomass, mitigating the negative effects of residue removal by adding to stable soil C pools. In a no-till continuous corn bioenergy system in the northern US Corn Belt, we used 13CO2 pulse labeling to trace plant C from a winter rye (Secale cereale) cover crop into different soil C pools for 2 years following rye cover crop termination. Corn stover left as residue (30% of total stover) contributed 66, corn roots 57, …

Increased C3 Productivity In Midwestern Lawns Since 1982 Revealed By Carbon Isotopes In Amanita Thiersii, Erik A. Hobbie, Brian A. Schubert, Joseph M. Craine, Ernst Linder, Anne Pringle

Faculty Publications

How climate and rising carbon dioxide concentrations (pCO2) have influenced competition between C3 and C4 plants over the last 50 years is a critical uncertainty in climate change research. Here we used carbon isotope (δ13C) values of the saprotrophic lawn fungus Amanita thiersii to integrate the signal of C3 and C4 carbon in samples collected between 1982 and 2009 from the Midwestern USA. We then calculated 13C fractionation (Δ) to assess the balance between C3 and C4 photosynthesis as influenced by mean annual temperature (MAT), mean annual precipitation over a 30 year period (MAP‐30), and pCO2. Sporocarp Δ correlated negatively …

Applying Population And Community Ecology Theory To Advance Understanding Of Belowground Biogeochemistry, Robert W. Buchkowski, Mark A. Bradford, A. Stuart Grandy, Oswald J. Schmitz, William R. Wieder

Faculty Publications

Approaches to quantifying and predicting soil biogeochemical cycles mostly consider microbial biomass and community composition as products of the abiotic environment. Current numerical approaches then primarily emphasise the importance of microbe–environment interactions and physiology as controls on biogeochemical cycles. Decidedly less attention has been paid to understanding control exerted by community dynamics and biotic interactions. Yet a rich literature of theoretical and empirical contributions highlights the importance of considering how variation in microbial population ecology, especially biotic interactions, is related to variation in key biogeochemical processes like soil carbon formation. We demonstrate how a population and community ecology perspective can …

The Dominion Range Ice Core, Queen Maud Mountains, Antarctica - General Site And Core Characteristics With Implications, Paul A. Mayewski, Mark S. Twickler, W. Berry Lyons, Mary Jo Spencer, Debra A. Meese, Anthony J. Gow, Pieter M. Grootes, Todd Sowers, M. Scott Watson, Eric Saltzman

Faculty Publications

The Transantarctic Mountains of East Antarctica provide a new milieu for retrieval of ice-core records. We report here on the initial findings from the first of these records, the Dominion Range ice-core record. Sites such as the Dominion Range are valuable for the recovery of records detailing climate change, volcanic activity, and changes in the chemistry of the atmosphere. The unique geographic location of this site and a relatively low accumulation rate combine to provide a relatively long record of change for this potentially sensitive climatic region. As such, information concerning the site and general core characteristics are presented, including …

Reconciling Opposing Soil Processes In Row-Crop Agroecosystems Via Soil Functional Zone Management, Alwyn Williams, Adam S. Davis, Andrea Jilling, A. Stuart Grandy, Roger T. Koide, David A. Mortensen, Richard G. Smith, Sieglinde S. Snapp, Kurt A. Spokas, Anthony C. Yannarell, Nicholas R. Jordan

Faculty Publications

Sustaining soil productivity in agricultural systems presents a fundamental agroecological challenge: nutrient provisioning depends upon aggregate turnover and microbial decomposition of organic matter (SOM); yet to prevent soil depletion these processes must be balanced by those that restore nutrients and SOM (soil building processes). These nutrient provisioning and soil building processes are inherently in conflict; management practices that create spatial separation between them may enable each to occur effectively within a single growing season, thereby supporting high crop yield while avoiding soil depletion. Soil functional zone management (SFZM), an understudied but increasingly adopted strategy for annual row-crop production, may help …

Development Of Scenarios For Land Cover, Population Density, Impervious Cover, And Conservation In New Hampshire, 2010–2100, Alexandra M. Thorn, Cameron P. Wake, Curt D. Grimm, Clayton R. Mitchell, Madeleine M. Mineau, Scott V. Ollinger

Faculty Publications

Future changes in ecosystem services will depend heavily on changes in land cover and land use, which, in turn, are shaped by human activities. Given the challenges of predicting long-term changes in human behaviors and activities, scenarios provide a framework for simulating the long-term consequences of land-cover change on ecosystem function. As input for process-based models of terrestrial and aquatic ecosystem function, we developed scenarios for land cover, population density, and impervious cover for the state of New Hampshire for 2020–2100. Key drivers of change were identified through information gathered from six sources: historical trends, existing plans relating to New …

A Coupled Terrestrial And Aquatic Biogeophysical Model Of The Upper Merrimack River Watershed, New Hampshire, To Inform Ecosystem Services Evaluation And Management Under Climate And Land-Cover Change, Nihar R. Samal, Wilfred M. Wollheim, Shantar Zuidema, Robert J. Stewart, Zaixing Zhou, Madeleine M. Mineau, Mark E. Borsuk, Kevin H. Gardner, Stanley J. Glidden, Tao Huang, David A. Lutz, Georgia Mayrommati, Alexandra M. Thorn, Cameron P. Wake, Matthew Huber

Faculty Publications

Accurate quantification of ecosystem services (ES) at regional scales is increasingly important for making informed decisions in the face of environmental change. We linked terrestrial and aquatic ecosystem process models to simulate the spatial and temporal distribution of hydrological and water quality characteristics related to ecosystem services. The linked model integrates two existing models (a forest ecosystem model and a river network model) to establish consistent responses to changing drivers across climate, terrestrial, and aquatic domains. The linked model is spatially distributed, accounts for terrestrial–aquatic and upstream–downstream linkages, and operates on a daily time-step, all characteristics needed to understand regional …