Advances In The Understanding Of Sourcing And Fate Of Pyrogenic Organic Matter In The Environment,
2020
Old Dominion University
Advances In The Understanding Of Sourcing And Fate Of Pyrogenic Organic Matter In The Environment, Aleksandar Ivaylov Goranov
Chemistry & Biochemistry Theses & Dissertations
With higher occurrences of forest fires worldwide, there has been an increase in scientific interest surrounding the chemistry of pyrogenic organic matter (pyOM). The main structural components of pyOM, the condensed aromatic compounds (ConAC), exhibit intriguing physico-chemical properties and have been one of the main focuses of biogeochemical research. The overwhelmingly large number of scientific articles regarding pyOM and ConAC are guided by the assumption that ConAC in the environment are exclusively of pyrogenic origin, even though some recent studies have suggested that some of these ConAC could also be derived from non-pyrogenic radical-driven processes. To evaluate this controversial proposition, …
Sodium-Calcium Ratios In The Planktic Foraminifera Trilobatus Sacculifer As A Proxy For Sea Surface Salinity,
2020
Old Dominion University
Sodium-Calcium Ratios In The Planktic Foraminifera Trilobatus Sacculifer As A Proxy For Sea Surface Salinity, Colton Steele Watkins
OES Theses and Dissertations
Recent culture and field studies have found a significant positive correlation between seawater salinity and the incorporation of sodium into foraminiferal calcite, suggesting a potential new proxy for reconstructing past changes in sea surface salinity (SSS) (Mezger et al., 2016 and Bertlich et al., 2018). In order to test the applicability of this new proxy in an open-ocean setting, Na/Ca ratios in the planktic foraminifera Trilobatus sacculifer (T. sacculifer Na/Ca) were measured from a suite of sediment core tops spanning a natural salinity gradient from the North Atlantic subtropical gyre to the South Atlantic subtropical gyre. Initial results from …
Ideas And Perspectives: A Strategic Assessment Of Methane And Nitrous Oxide Measurements In The Marine Environment,
2020
University of Hawaiʻi at Mānoa
Ideas And Perspectives: A Strategic Assessment Of Methane And Nitrous Oxide Measurements In The Marine Environment, Samuel T. Wilson, Alia N. Al-Haj, Annie Bourbonnais, Claudia Frey, Robinson W. Fulweiler, John D. Kessler, Hannah K. Marchant, Jana Milucka, Nicholas E. Ray, Parv Suntharalingham, Brett F. Thornton, Robert C. Upstill-Goddard, Thomas S. Weber, Damian L. Arévalo-Martínez, Hermann W. Bange, Heather M. Benway, Daniele Bianchi, Alberto V. Borges, Bonnie X. Chang, Patrick M. Crill, Daniela A. Del Valle, Laura Fariás, Samantha B. Joye, Annette Kock, Jabrane Labidi, Cara C. Manning, John W. Pohlman, Gregor Rehder, Katy J. Sparrow, Philippe D. Tortell, Tina Treude, David L. Valentine
Faculty Publications
In the current era of rapid climate change, accurate characterization of climate-relevant gas dynamics-namely production, consumption, and net emissions-is required for all biomes, especially those ecosystems most susceptible to the impact of change. Marine environments include regions that act as net sources or sinks for numerous climateactive trace gases including methane (CH4) and nitrous oxide (N2O). The temporal and spatial distributions of CH4 and N2O are controlled by the interaction of complex biogeochemical and physical processes. To evaluate and quantify how these mechanisms affect marine CH4 and N2O cycling requires a combination of traditional scientific disciplines including oceanography, microbiology, and …
Assessing Microbial Residues In Soil As A Potential Carbon Sink And Moderator Of Carbon Use Efficiency,
2020
University of New Hampshire, Durham
Assessing Microbial Residues In Soil As A Potential Carbon Sink And Moderator Of Carbon Use Efficiency, Kevin M. Geyer, Jorg Schnecker, A. Stuart Grandy, Andreas Richter, Serita D. Frey
Faculty Publications
A longstanding assumption of glucose tracing experiments is that all glucose is microbially utilized during short incubations of ≤2 days to become microbial biomass or carbon dioxide. Carbon use efficiency (CUE) estimates have consequently ignored the formation of residues (non-living microbial products) although such materials could represent an important sink of glucose that is prone to stabilization as soil organic matter. We examined the dynamics of microbial residue formation from a short tracer experiment with frequent samplings over 72 h, and conducted a meta-analysis of previously published glucose tracing studies to assess the generality of these experimental results. Both our …
The Transition From Stochastic To Deterministic Bacterial Community Assembly During Permafrost Thaw Succession,
2020
University of New Hampshire, Durham
The Transition From Stochastic To Deterministic Bacterial Community Assembly During Permafrost Thaw Succession, Stacey J. Doherty, Robyn A. Barbato, A. Stuart Grandy, W. Kelley Thomas, Sylvain Monteux, Ellen Dorrepaal, Margareta Johansson, Jessica G. Ernakovich
Faculty Publications
The Northern high latitudes are warming twice as fast as the global average, and permafrost has become vulnerable to thaw. Changes to the environment during thaw leads to shifts in microbial communities and their associated functions, such as greenhouse gas emissions. Understanding the ecological processes that structure the identity and abundance (i.e., assembly) of pre- and post-thaw communities may improve predictions of the functional outcomes of permafrost thaw. We characterized microbial community assembly during permafrost thaw using in situ observations and a laboratory incubation of soils from the Storflaket Mire in Abisko, Sweden, where permafrost thaw has occurred over the …
Modeling Holocene Peatland Carbon Accumulation In North America,
2020
Purdue University
Modeling Holocene Peatland Carbon Accumulation In North America, Qianlai Zhuang, Sirui Wang, Bailu Zhao, Filipe Aires, Catherine Prigent, Zicheng Yu, Jason K. Keller, Scott Bridgham
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Peatlands are a large carbon reservoir. Yet the quantification of their carbon stock still has a large uncertainty due to lacking observational data and well‐tested peatland biogeochemistry models. Here, a process‐based peatland model was calibrated using long‐term peat carbon accumulation data at multiple sites in North America. The model was then applied to quantify the peat carbon accumulation rates and stocks within North America over the last 12,000 years. We estimated that 85–174 Pg carbon was accumulated in North American peatlands over the study period including 0.37–0.76 Pg carbon in subtropical peatlands. During the period from 10,000 to 8,000 years …
Fungal Community Structure And Function Shifts With Atmospheric Nitrogen Deposition,
2020
University of New Hampshire, Durham
Fungal Community Structure And Function Shifts With Atmospheric Nitrogen Deposition, Jessica A. M. Moore, Mark A. Anthony, Gregory J. Pec, Lidia K. Trocha, Artur Trzebny, Kevin M. Geyer, Linda T. A. Van Diepen, Serita D. Frey
Faculty Publications
Fungal decomposition of soil organic matter depends on soil nitrogen (N) availability. This ecosystem process is being jeopardized by changes in N inputs that have resulted from a tripling of atmospheric N deposition in the last century. Soil fungi are impacted by atmospheric N deposition due to higher N availability, as soils are acidified, or as micronutrients become increasingly limiting. Fungal communities that persist with chronic N deposition may be enriched with traits that enable them to tolerate environmental stress, which may trade-off with traits enabling organic matter decomposition. We hypothesized that fungal communities would respond to N deposition by …
Plant Invasion Impacts On Fungal Community Structure And Function Depend On Soil Warming And Nitrogen Enrichment,
2020
University of New Hampshire, Durham
Plant Invasion Impacts On Fungal Community Structure And Function Depend On Soil Warming And Nitrogen Enrichment, Mark A. Anthony, K. A. Stinson, Jessica A. M. Moore, Serita D. Frey
Faculty Publications
The impacts of invasive species on biodiversity may be mitigated or exacerbated by abiotic environmental changes. Invasive plants can restructure soil fungal communities with important implications for native biodiversity and nutrient cycling, yet fungal responses to invasion may depend on numerous anthropogenic stressors. In this study, we experimentally invaded a long-term soil warming and simulated nitrogen deposition experiment with the widespread invasive plant Alliaria petiolata (garlic mustard) and tested the responses of soil fungal communities to invasion, abiotic factors, and their interaction. We focused on the phytotoxic garlic mustard because it suppresses native mycorrhizae across forests of North America. We …
Potential Virus-Mediated Nitrogen Cycling In Oxygen-Depleted Oceanic Waters,
2020
Old Dominion University
Potential Virus-Mediated Nitrogen Cycling In Oxygen-Depleted Oceanic Waters, M. Consuelo Gazitúa, Dean R. Vik, Simon Roux, Ann C. Gregory, Benjamin Bolduc, Brittany Widner, Margaret R. Mulholland, Steven J. Hallam, Osvaldo Ulloa, Matthew B. Sullivan
OES Faculty Publications
Viruses play an important role in the ecology and biogeochemistry of marine ecosystems. Beyond mortality and gene transfer, viruses can reprogram microbial metabolism during infection by expressing auxiliary metabolic genes (AMGs) involved in photosynthesis, central carbon metabolism, and nutrient cycling. While previous studies have focused on AMG diversity in the sunlit and dark ocean, less is known about the role of viruses in shaping metabolic networks along redox gradients associated with marine oxygen minimum zones (OMZs). Here, we analyzed relatively quantitative viral metagenomic datasets that profiled the oxygen gradient across Eastern Tropical South Pacific (ETSP) OMZ waters, assessing whether OMZ …
Under-Ice Phytoplankton Blooms: Shedding Light On The "Invisible" Part Of Arctic Primary Production,
2020
Old Dominion University
Under-Ice Phytoplankton Blooms: Shedding Light On The "Invisible" Part Of Arctic Primary Production, Mathieu Ardyna, C. J. Mundy, Nicolas Mayot, Lisa C. Matthes, Laurent Oziel, Christopher Horvat, Eva Leu, Philipp Assmy, Victoria Hill, Patricia A. Matrai, Matthew Gale, Igor A. Melnikov, Kevin R. Arrigo
OES Faculty Publications
The growth of phytoplankton at high latitudes was generally thought to begin in open waters of the marginal ice zone once the highly reflective sea ice retreats in spring, solar elevation increases, and surface waters become stratified by the addition of sea-ice melt water. In fact, virtually all recent large-scale estimates of primary production in the Arctic Ocean (AO) assume that phytoplankton production in the water column under sea ice is negligible. However, over the past two decades, an emerging literature showing significant under-ice phytoplankton production on a pan-Arctic scale has challenged our paradigms of Arctic phytoplankton ecology and phenology. …
Stoichiometrically Coupled Carbon And Nitrogen Cycling In The Microbial-Mineral Carbon Stabilization Model Version 1.0 (Mimics-Cn V1.0),
2020
University of New Hampshire, Durham
Stoichiometrically Coupled Carbon And Nitrogen Cycling In The Microbial-Mineral Carbon Stabilization Model Version 1.0 (Mimics-Cn V1.0), Emily Kyker-Snowman, William R. Wieder, Serita D. Frey, A. Stuart Grandy
Faculty Publications
Explicit consideration of microbial physiology in soil biogeochemical models that represent coupled carbon–nitrogen dynamics presents opportunities to deepen understanding of ecosystem responses to environmental change. The MIcrobial-MIneral Carbon Stabilization (MIMICS) model explicitly represents microbial physiology and physicochemical stabilization of soil carbon (C) on regional and global scales. Here we present a new version of MIMICS with coupled C and nitrogen (N) cycling through litter, microbial, and soil organic matter (SOM) pools. The model was parameterized and validated against C and N data from the Long-Term Inter-site Decomposition Experiment Team (LIDET; six litter types, 10 years of observations, and 13 sites …
Water Quality Assessment In The Occurrence Of Acanthaster Spp. (Crown-Of-Thorns Starfish, Cots) On Coral Reefs In Menjangan Island, Bali, Indonesia,
2020
Institute for Marine Research and Observation, Ministry of Marine Affairs and Fisheries, Bali 82251, Indonesia
Water Quality Assessment In The Occurrence Of Acanthaster Spp. (Crown-Of-Thorns Starfish, Cots) On Coral Reefs In Menjangan Island, Bali, Indonesia, Novia Arinda Pradisty, Eghbert Elvan Ampou, Rizki Hanintyo
Makara Journal of Science
Aquatic stressors are known to cause biological impairment that can result in biodiversity loss in several Marine Protected Areas (MPA), including in Menjangan Island, West Bali National Park. The objectives of this study were to correlate the changes in water quality parameters with the biological effect of Crown-of-Thorns starfish (CoTS) population dynamics and to assess the most applicable parameters for continuous environmental monitoring. Field observations and surveys were conducted three times in 2017, during the wet season, dry season and season transition, in order to assess the effect of seasonal variability. Redundancy Analysis (RDA) was performed to determine the relationship …
Sea-Ice Production And Air/Ice/Ocean/Biogeochemistry Interactions In The Ross Sea During The Pipers 2017 Autumn Field Campaign,
2020
Old Dominion University
Sea-Ice Production And Air/Ice/Ocean/Biogeochemistry Interactions In The Ross Sea During The Pipers 2017 Autumn Field Campaign, S. F. Ackley, S. Stammerjohn, T. Maksym, M. Smith, J. Cassano, P. Guest, J.-L. Tison, B. Delille, B. Loose, Peter N. Sedwick, L. Depace, L. Roach, J. Parno
OES Faculty Publications
The Ross Sea is known for showing the greatest sea-ice increase, as observed globally, particularly from 1979 to 2015. However, corresponding changes in sea-ice thickness and production in the Ross Sea are not known, nor how these changes have impacted water masses, carbon fluxes, biogeochemical processes and availability of micronutrients. The PIPERS project sought to address these questions during an autumn ship campaign in 2017 and two spring airborne campaigns in 2016 and 2017. PIPERS used a multidisciplinary approach of manned and autonomous platforms to study the coupled air/ice/ocean/biogeochemical interactions during autumn and related those to spring conditions. Unexpectedly, the …
Assessment Of Switchgrass-Based Bioenergy Supply Using Gis-Based Fuzzy Logic And Network Optimization In Missouri (U.S.A.),
2020
Montclair State University
Assessment Of Switchgrass-Based Bioenergy Supply Using Gis-Based Fuzzy Logic And Network Optimization In Missouri (U.S.A.), Gia Nguyen, Erik Lyttek, Pankaj Lal, Taylor Wieczerak, Pralhad Burli
Department of Earth and Environmental Studies Faculty Scholarship and Creative Works
Bioenergy has been globally recognized as one of the sustainable alternatives to fossil fuels. An assured supply of biomass feedstocks is a crucial bottleneck for the bioenergy industry emanating from uncertainties in land-use changes and future prices. Analytical approaches deriving from geographical information systems (GIS)-based analysis, mathematical modeling, optimization analyses, and empirical techniques have been widely used to evaluate the potential for bioenergy feedstock. In this study, we propose a three-phase methodology integrating fuzzy logic, network optimization, and ecosystem services assessment to estimate potential bioenergy supply. The fuzzy logic analysis uses multiple spatial criteria to identify suitable biomass cultivating regions. …
Using Terrestrial Laser Scanning To Characterize Peatland Microtopography And Assess Tree Growth Responses To Elevated Temperature And Co2,
2020
Boise State University
Using Terrestrial Laser Scanning To Characterize Peatland Microtopography And Assess Tree Growth Responses To Elevated Temperature And Co2, Jake D. Graham
Boise State University Theses and Dissertations
Northern peatlands are a major terrestrial carbon (C) store, with an annual sink of 0.1 Pg C yr-1 and a total storage estimate of 547 Pg C. Northern peatlands are also major contributors of atmospheric methane, a potent greenhouse gas. The microtopography of peatlands helps modulate peatland carbon fluxes; however, there is a lack of quantitative characterizations of microtopography in the literature. The lack of formalized schemes to characterize microtopography makes comparisons between studies difficult. Further, many land surface models do not accurately simulate peatland C emissions, in part because they do not adequately represent peatland microtopography and hydrology. …
Freshwater Endmembers Impacting Carbonate Chemistry In The Mississippi Sound,
2020
The University of Southern Mississippi
Freshwater Endmembers Impacting Carbonate Chemistry In The Mississippi Sound, Allison Savoie
Master's Theses
Coastal ecosystems are highly dynamic areas for carbon cycling and are likely to be negatively impacted by increasing ocean acidification. This research focused on dissolved inorganic carbon (DIC) and total alkalinity (TA) in the Mississippi Sound in order to understand the influence of local rivers that supply alkalinity to the area and buffer against ocean acidification. This area receives large fluxes of freshwater from local rivers, in addition to episodic inputs from the Mississippi River through a human-built diversion, the Bonnet Carré Spillway. Sites in the Mississippi Sound were sampled monthly during August 2018 to November 2019 and at weekly …
Microbial Diversity Drives Carbon Use Efficiency In A Model Soil,
2020
University of Massachusetts, Amherst
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 …
Plant And Soil Responses To Sediment Deposition And Nutrient Enrichment In Healthy, Deteriorating, And Newly Created Coastal Marshes In Barataria Basin, Louisiana: Implications For Mississippi River Sediment Diversions,
2020
Louisiana State University
Plant And Soil Responses To Sediment Deposition And Nutrient Enrichment In Healthy, Deteriorating, And Newly Created Coastal Marshes In Barataria Basin, Louisiana: Implications For Mississippi River Sediment Diversions, Gina N. Groseclose
LSU Master's Theses
To offset wetland loss in the Mississippi River Delta, sediment diversions that will re-introduce river water and sediment into wetlands are being planned for the lower Mississippi River. River diversions will also deliver high nutrient loads, which may reduce belowground plant productivity, reducing inputs of organic matter important for marsh accretion to keep pace with sea-level rise. However, belowground productivity responses to the combinatory effects of sediment and nutrients are unknown. To test the hypotheses that nutrient enrichment and sediment deposition interact to influence vegetation structure, belowground plant productivity and decomposition, and surface accretion, a field experiment was implemented in …
Phosphorus Variability In The Area Of Influence Of The Mid-Barataria Sediment Diversion,
2020
Louisiana State University
Phosphorus Variability In The Area Of Influence Of The Mid-Barataria Sediment Diversion, Peter Mates
LSU Master's Theses
Man-made levees along the lower Mississippi River prevent delivery of sediment from building and maintaining Louisiana’s coastal wetlands. The Mid-Barataria sediment diversions is designed to reintroduce Mississippi River water, sediment, and nutrients into the sediment-starved Barataria Basin. Phosphorus (P) is an important macronutrient for regulating primary production in coastal marine ecosystems. Wetlands can serve as a sink or source for phosphorus to the overlying water column through various retention and release processes, dependent on concentration. Louisiana coastal systems can be phosphorus limited due to much higher concentrations of bioavailable Nitrogen in river water. The high soluble molar N:P ( >50:1) …
Decomposability Of Soil Organic Matter Over Time: The Soil Incubation Database (Sidb, Version 1.0) And Guidance For Incubation Procedures,
2020
Northern Arizona University
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, …
