Biogeochemistry Commons^™

Crop Rotational Complexity Affects Plant-Soil Nitrogen Cycling During Water Deficit, Timothy M. Bowles, Andrea Jilling, Karen Moran-Rivera, Jorg Schnecker, A. Stuart Grandy

Faculty Publications

One of the biggest environmental challenges facing agriculture is how to both supply and retain nitrogen (N), especially as precipitation becomes more variable with climate change. We used a greenhouse experiment to assess how contrasting histories of crop rotational complexity affect plant-soil-microbe interactions that govern N processes, including during water stress. With higher levels of carbon and N cycling hydrolytic enzymes, higher mineral-associated organic matter N concentrations, and an altered microbial community, soils from the most complex rotation enabled 80% more corn N uptake under two moisture regimes, compared to soil from monoculture corn. Higher levels of plant N likely …

Inverse Modeling Of Atmospheric Ch4 And Δ13C-Ch4 Measurements From Surface Observation Sites To Understand Trends In Global Methane Emissions Over More Than Three Decades, Sayantani Karmakar

Dissertations and Theses

Methane (CH₄) is the second most important greenhouse gas with a radiative forcing of 0.97 W/m² including both direct and indirect effects and a global warming potential of 28 over a 100-year time horizon. Unlike CO₂ whose rate of growth in the atmosphere has remained positive and increased in recent decades, the behavior of atmospheric methane is considerably more complex and is much less understood on account of the spatiotemporal variability of its emissions which include biogenic (e.g., wetlands, ruminants, rice agriculture), thermogenic (fossil fuels), and pyrogenic (i.e., biomass burning) sources. After sustained growth during most …

Dynamics And Turnover Of Lipid And Protein Domains In Cells And Supported Bilayers, Alan Weisgerber

Electronic Theses and Dissertations

Protein and lipid clustering is an important mechanism for cell processes such as exo- and endo-cytosis and creating functional signaling complexes. It has been seen that both lipids and proteins are involved with the formation of cluster domains on cell membranes, yet little is known about the interplay between the two. In this work I began with visualizing lipid sorting to artificially induced curvature in supported lipid bilayers, with lipid tails affecting the sorting differently to curvature. These results demonstrate that lipids sort to curvature on curved, supported lipid bilayers. The sorting depends on the number of lipids in the …

Evidence For Metabolic Diversity In Meso-Neoproterozoic Stromatolites (Vazante Group, Brazil), Flavia Callefo, Fresia Ricardi-Branco, Mirian Mírian Liza Alves Forancelli Pacheco, Alexandre Ribeiro Cardoso, Nora Noffke, Verônica De Carvalho Teixeira, Itamar Tomio Neckel, Lara Maldanis, Emma Bullock, Dina Bower, Adalene Moreira Silva, Dario Ferreira Sanchez, Fabio Rodrigues, Douglas Galante

OES Faculty Publications

Deciphering the evolution of ecological interactions among the metabolic types during the early diversification of life on Earth is crucial for our understanding of the ancient biosphere. The stromatolites from the genus Conophyton cylindricus represent a datum for the Proterozoic (Meso to Neoproterozoic) on Earth. Their typical conical shape has been considered a result of a competition between microorganisms for space, light and nutrients. Well-preserved records of this genus from the "Paleontological Site of Cabeludo ", Vazante Group, São Francisco Craton (Southern Brazil) present in situ fossilized biofilms, containing preserved carbonaceous matter. Petrographic and geochemical analyses revealed an alternation between …

Sediment Mineralogy Influences The Rate Of Microbial Sulfate Reduction In Marine Sediments, Chin Yik Lin, Harold J. Bradbury, Gilad Antler, David J. Burdige, Thomas D. Bennett, Shichun Li, Alexandra V. Turchyn

OES Faculty Publications

Sedimentary microbial communities play a critical role in the global carbon cycle, oxidizing deposited organic carbon and thus influencing the type of carbon buried from Earth's surface. The rate of microbial metabolism within sedimentary microbial communities is often linked to the lability and amount of organic carbon deposited. Here we show that, in pure culture, for sulfate-reducing bacteria (Desulfovibrio bizertensis) the rate of microbial sulfate reduction is a function of the proportion of clay minerals present in the incubation vials. We argue that the presence of clay minerals stimulates the growth of the sulfate-reducing bacteria and the rate …

Editorial: Carbon Cycling In Aquatic Critical Zones, Peng Yao, Thomas S. Bianchi, David J. Burdige, Xiaojuan Feng, Peter A. Raymond

OES Faculty Publications

No abstract provided.

Insights Into The Deglacial Variability Of Phytoplankton Community Structure In The Eastern Equatorial Pacific Ocean Using [231Pa/230Th]Xs And Opal-Carbonate Fluxes, Danielle Schimmenti, Franco Marcantonio, Christopher T. Hayes, Jennifer Hertzberg, Matthew Schmidt, John Sarao

OES Faculty Publications

Fully and accurately reconstructing changes in oceanic productivity and carbon export and their controls is critical to determining the efficiency of the biological pump and its role in the global carbon cycle through time, particularly in modern CO₂ source regions like the eastern equatorial Pacific (EEP). Here we present new high-resolution records of sedimentary ²³⁰Th-normalized opal and nannofossil carbonate fluxes and [²³¹Pa/²³⁰Th]xs ratios from site MV1014-02-17JC in the Panama Basin. We find that, across the last deglaciation, phytoplankton community structure is driven by changing patterns of nutrient (nitrate, iron, and silica) availability which, in …

Ooi Biogeochemical Sensor Data: Best Practices And User Guide. Version 1.0.0., Hilary I. Palevsky, Sophie Clayton, Dariia Atamanchuk, Roman Battisti, Jennifer Batryn, Annie Bourbonnais, Ellen M. Briggs, Filipa Carvalho, Alison P. Chase, Rachel Eveleth, Rob Fatland, Kristen E. Fogaren, Jonathan Peter Fram, Susan E. Hartman, Isabela Le Bras, Cara C.M. Manning, Joseph A. Needoba, Merrie Beth Neely, Hilde Oliver, Andrew C. Reed, Jennie E. Rheuban, Christina Schallenberg, Michael F. Vardaro, Ian Walsh, Christopher Wingard

OES Faculty Publications

The OOI Biogeochemical Sensor Data Best Practices and User Guide is intended to provide current and prospective users of data generated by biogeochemical sensors deployed on the Ocean Observatories Initiative (OOI) arrays with the information and guidance needed for them to ensure that the data is science-ready. This guide is aimed at researchers with an interest or some experience in ocean biogeochemical processes. We expect that users of this guide will have some background in oceanography, however we do not assume any prior experience working with biogeochemical sensors or their data. While initially envisioned as a “cookbook” for end users …

Spatial Geochemical Changes In Central And East Texas Soils Over Time Resulting From Human Decomposition, Isabela Marisol Overturf

CMC Senior Theses

Human decomposition is studied to aid forensic investigations and better understand the impact of cemeteries on urban resources like soil and groundwater. The purpose of this study was to identify changes in soil geochemistry at and around a human grave to search for lateral nutrient movement and possibly identify new patterns in elemental concentrations that could be used in estimating post-mortem intervals (PMIs). At the Forensic Anthropology Research Facility (FARF) at Texas State San Marcos, soil samples were collected from a shallow grave over the course of 54 days to conduct analysis for organic matter content, texture, pH, and bulk …

Validation Of The Use Of Clathromorphum Compactum Growth And Skeletal Δ18o As A Proxy For Seawater Conditions, Teagan Mcmahon

Pitzer Senior Theses

Crustose coralline algae (CCA) are important organisms that create benthic habitat in the photic zone of oceans worldwide. CCAs mechanisms of photosynthesis and calcification may, in some cases, make them vulnerable to climate change and ocean acidification. Therefore, CCA are important not only for their ecological role within ecosystems but also for their ability to indicate the effects that ocean acidification and climate change may have on other marine calcifying organisms. Some species of CCA are known to be useful recorders of paleo oceanic conditions. These climate archives and reconstructions of past environmental conditions are important for understanding past changes …

Controls On Carbon Gas Fluxes From A Temperate Forest Soil, Natalie A. White, Ruth K. Varner, Clarice R. Perryman

Honors Theses and Capstones

Forest soils consume atmospheric methane (CH₄), serving as a major global CH₄ sink that uptake an estimated 22 ± 12 Tg of CH₄ per year. Temperature and soil moisture have been identified as key controls of the microbial consumption of CH₄ in forest soils. Climate-driven warming and changing moisture regimes may impact forest soils’ role in the carbon cycle, and recent works suggests that forests could become weaker CH₄ sinks. Long-term monitoring sites can capture these changes, leading to better predictions of CH₄ exchange between the atmosphere and soils under climate change. This study …

Stable Isotope Analysis Of A Platecarpus Tympaniticus (Squamata, Mosasauridae) With Actinocamax Sternbergi (Mollsuca, Belemnoidea) Reveals Possible Endothermic Thermoregulation, Mitchell Lukens

Master's Theses or Doctor of Nursing Practice

Mosasaurs, ancient marine reptiles, dominated the late Cretaceous oceans. However, their ecological success is a contentious topic. Were they ectothermic, like their modern relatives the varanid lizards? Or endothermic like extant marine mammals? Stable isotopes can reveal temperature and physiological variances within skeletons, but do not differentiate between body temperature and ambient environmental temperature. A rare mosasaur specimen from the Smoky Hill Chalk of a partial, articulated Platecarpus tympaniticus with stomach contents of belemnites provides a possible direct temperature contrast between predator and prey. The belemnites, related to modern coleoids, are identified as Actinocamax sternbergi. These animals possessed body …

Combined Effects Of Temperature And Heavy Metals On The Performance Of The Giant Salmonfly., James Frakes, Amanda Andreas, Benjamin P. Colman, Aurthur Woods

Graduate Student Theses, Dissertations, & Professional Papers

In many freshwater ecosystems, communities of aquatic insects are facing the combined stresses of warmer waters due to climate change and increased exposure to heavy metal toxicants. Although each stressor may threaten aquatic insects independently, they also likely interact in important ways to affect insect physiology and performance. Here we investigate this potential interaction using two populations of aquatic nymphs of the giant salmonfly, Pteronarcys californica, collected from adjacent rivers in Montana: naïve individuals from Rock Creek, a relatively pristine stream, and individuals from the Upper Clark Fork River, which has a history of heavy metal pollution and higher …

Unearthing The Effects Of European-American Settlement On A Northeast Ohio Kettle Lake Through Diatom Stratigraphy, Justine Paul A. Berina

Senior Independent Study Theses

Recently, wetland conservation has highlighted the necessity for assessing limnological changes following European-American settlement. A prior study at Brown's Lake (northeast Ohio) identified a stratigraphic sequence that shows an abrupt transition from organic-rich muds to several centimeters of a bright loess layer, then a recovery to organic-rich sediments near the top. Based on ²¹⁰Pb dates, the loess deposition occurred before 1846 CE, when a growing population cleared trees and farmed intensively. Likewise, organics had recovered after 1950 CE, when people abandoned farmland and practiced conservation tillage. However, the effects of settlement on limnology are poorly known. Diatoms (microscopic algae; …

Frayed Connections: How Long-Term Nitrogen Additions Disrupt Plant-Soil Interactions And The Carbon Cycle Of A Temperate Forest, Brooke A. Eastman

Graduate Theses, Dissertations, and Problem Reports (ETD)

Forests are expected to mitigate some of the negative effects of climate change by sequestering anthropogenic carbon (C) from the atmosphere, but the degree to which they drawn down C will depend on the availability of key nutrients, such as nitrogen (N). There is a fair amount of uncertainty in the future of the forest C sink, mostly owing to the fate of soil organic matter (SOM) and soil heterotrophic respiration to future conditions. In N limited systems, plants allocate a significant amount of their photosynthate belowground for the acquisition of nutrients, but under conditions of chronic N deposition, plants …

The Role Of Microorganisms In Rare Earth Elements Bioaccumulation, Maedeh Soleimanifar

Dissertations

Rare earth elements (REE) are valuable raw materials in our modern life. Extensive REE application from electronic devices to medical instruments and wind turbines, and non-uniform distribution of these resources around the world, make them strategically and economically important for countries. Current REE physical and chemical mining and recycling methods could have negative environmental consequences, and biologically-mediated techniques could be applied to overcome this issue.

In this research, the first objective is to investigate the bioextraction of cerium oxide and neodymium oxide nanoparticles (REE-NP) by a pure culture Methylobacterium extorquens AM1 (ATCC®14718™). Results show that adding up to 1,000 ppm …

Identifying Biogeochemical Factors Responsible For The Cyclical Precipitation Of Sphalerite And Galena In Low Temperature Mississippi Valley Type Ore Deposits, Daniel John Makowsky

Theses and Dissertations

Mississippi Valley Type (MVT) lead and zinc deposits provide a significant source of sedimentary galena and sphalerite. However, geochemical characteristics and genesis including the source and production of hydrogen sulfide required for galena and sphalerite ore formation and the reasoning for quick, episodic mineralization is not fully understood. By simulating regional MVT brines, the input and effect of biological by-products during the development of these ores as well as the cause of cyclicity within MVT deposits have been observed. Experiments using compositions from MVT fluid inclusions were conducted over two-week periods. Variables during the experiments included temperature, CO2, hydrogen sulfide …

Fungal Community And Functional Responses To Soil Warming Are Greater Than For Soil Nitrogen Enrichment, Mark A. Anthony, Melissa A. Knorr, Jessica A. M. Moore, M. Simpson, Serita D. Frey

Faculty Publications

Soil fungi are key regulators of forest carbon cycling and their responses to global change have effects that ripple throughout ecosystems. Global changes are expected to push many fungi beyond their environmental niches, but there are relatively few studies involving multiple, simultaneous global change factors. Here, we studied soil fungal diversity, community composition, co-occurrence patterns, and decomposition gene responses to 10 years of soil warming and nitrogen addition, alone and in combination. We specifically examined whether there were fungal community characteristics that could explain changes in soil carbon storage and organic matter chemistry in chronically warmed and fertilized soil. We …

Iron Geochemistry Across An Estuary-To-Coastal Gradient, Lissett G. Diaz

Honors Theses

Iron is a ubiquitous earth element that participates in biogeochemical processes that occur in marine sediments. Microorganisms utilize iron for many purposes, including cell growth, conserving energy, and for maintaining metabolic activity. In coastal sedimentary settings, understanding the redox reactions involving ferric iron, Fe³⁺, and ferrous iron, Fe²⁺, in its solid phase and pore-water phases, respectively, enable an appreciation of biogeochemical transformations occurring in the coastal zone. In this study, iron concentrations in sediment of ranging permeability were determined at four stations marking an estuary-coast transition zone in Singleton Swash in Myrtle Beach, South Carolina. The …

Kudzu Invasion And Control In Southern Upland Forests Of Mississippi, Gina M. Profetto

LSU New Orleans Theses and Dissertations

Kudzu, Pueraria montana var. lobata (Willd.), is a common invasive species throughout the American South. In southern upland mixed oak-pine forests of Mississippi, kudzu invasion generally and indiscriminately suppressed the pre-invasion plant community. Three different control methods reduced kudzu density but differed in the level of reduction achieved and in their effects on the pre-existing plant community. A combination of burning and herbicides produced the most desirable outcome in terms of restoring the pre-invasion community. Kudzu invasion significantly increased nitrate pools compared to control sites, but had no effect on ammonium or nitrite, or on the microbial processes of mineralization …

Soil Accretion And Mass Accumulation In A Scrub And Fringe Mangrove Forest In Biscayne Bay, Florida, Jessica A. Jacobs

USF Tampa Graduate Theses and Dissertations

This study estimated soil accretion and mass (organic carbon (OC), total nitrogen (TN), and total soil) accumulation in a scrub and fringe mangrove forest in Biscayne Bay, FL, to assess how forests of different morphologies (scrub vs. fringe) have kept pace with recently accelerating rates of sea-level rise. Accretion rates (AR) were estimated using the Constant Initial Concentration (CIC) model of lead-210 deposition and it was determined that the scrub forest has accreted at 1.3 ± 0.2 mm yr-1 over 75 years and the fringe forest at 2.8 ± 0.4 mm yr-1 over 92 years. The fringe forest estimate met …

Nutrient Cycling In Tropical And Temperate Coastal Waters: Is Latitude Making A Difference?, Christian Lønborg, Moritz Müller, Edward C. V. Butler, Shan Jiang, Seng Keat Ooi, Dieu Huong Trinh, Pui Yee Wong, Suryati M. Ali, Chun Cui, Wee Boon Siong, Erik S. Yando, Daniel A. Friess, Judith A. Rosentreter, Bradley D. Eyre, Patrick Martin

Biological Sciences Faculty Publications

Tropical coastal waters are highly dynamic and amongst the most biogeochemically active zones in the ocean. This review compares nitrogen (N) and phosphorus (P) cycles in temperate and tropical coastal waters. We review the literature to identify major similarities and differences between these two regions, specifically with regards to the impact of environmental factors (temperature, sunlight), riverine inputs, groundwater, lateral fluxes, atmospheric deposition, nitrogen fixation, organic nutrient cycling, primary production, respiration, sedimentary burial, denitrification and anammox. Overall, there are some similarities but also key differences in nutrient cycling, with differences relating mainly to temperature, sunlight, and precipitation amounts and patterns. …

Radiocarbon Analyses Quantify Peat Carbon Losses With Increasing Temperature In A Whole Ecosystem Warming Experiment, Rachel M. Wilson, Natalie A. Griffiths, Ate Visser, Karis J. Mcfarlane, Stephen D. Sebestyen, Keith C. Oleheiser, Samantha Bosman, Anya M. Hopple, Malak M. Tfaily, Randall K. Kolka, Paul J. Hanson, Joel E. Kostka, Scott D. Bridgham, Jason K. Keller, Jeffrey P. Chanton

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Climate warming is expected to accelerate peatland degradation and release rates of carbon dioxide (CO2) and methane (CH4). Spruce and Peatlands Responses Under Changing Environments is an ecosystem-scale climate manipulation experiment, designed to examine peatland ecosystem response to climate forcings. We examined whether heating up to +9 °C to 3 m-deep in a peat bog over a 7-year period led to higher C turnover and CO2 and CH4 emissions, by measuring 14C of solid peat, dissolved organic carbon (DOC), CH4, and dissolved CO2 (DIC). DOC, a major substrate for heterotrophic respiration, increased significantly with warming. There was no 7-year trend …

Prevention And Preparedness Of The Messina-Reggio Calabria Strait: An Earthquake Forecasting And Didactic Project, Francesco Di Stefano, Gioacchino Giampaolo Giuliani, Dimitar Ouzounov, Daniele Cataldi, Cristiano Fidani, Angelo D'Errico, Giulia Fioravanti

Mathematics, Physics, and Computer Science Faculty Articles and Research

This contribution is addressed to an introductive university course on the correlation existing between radon emission and earthquakes processes held following a flipped-class approach where students receive didactic materials prior to face-to-face lessons. This research was initially started to investigate the real correlation between Radon emission from the Earth and the occurrence of strong earthquakes by using measurements of hourly Radon flow variation. During quiet seismogenic conditions, we observe an unvarying level of Radon emission in the air. Before a strong earthquake, substantial variations of Radon (²²²Rn) concentration have been observed in the air, probably because of the …

Increasing The Spatial And Temporal Impact Of Ecological Research: A Roadmap For Integrating A Novel Terrestrial Process Into An Earth System Model, Emily Kyker-Snowman, Danica L. Lombardozzi, Gordon B. Bonan, Susan J. Cheng, Jeffrey S. Dukes, Serita D. Frey, Elin M. Jacobs, Risa Mcnellis, Joshua M. Rady, Nicholas G. Smith, R. Quinn Thomas, William R. Wieder, A. Stuart Grandy

Faculty Publications

Terrestrial ecosystems regulate Earth's climate through water, energy, and biogeochemical transformations. Despite a key role in regulating the Earth system, terrestrial ecology has historically been underrepresented in the Earth system models (ESMs) that are used to understand and project global environmental change. Ecology and Earth system modeling must be integrated for scientists to fully comprehend the role of ecological systems in driving and responding to global change. Ecological insights can improve ESM realism and reduce process uncertainty, while ESMs offer ecologists an opportunity to broadly test ecological theory and increase the impact of their work by scaling concepts through time …

Patterns And Trends Of Organic Matter Processing And Transport: Insights From The Us Long-Term Ecological Research Network, Tamara K. Harms, Peter M. Groffman, Lihini Aluwihare, Christopher Craft, William R. Wieder, Sarah E. Hobbie, Sara G. Baer, John M. Blair, Serita D. Frey, Christina K. Remucal, Jennifer A. Rudgers, Scott L. Collins, John S. Kominoski, Becky A. Ball, Lter Om Working Group

Faculty Publications

Organic matter (OM) dynamics determine how much carbon is stored in ecosystems, a service that modulates climate. We synthesized research from across the US Long-Term Ecological Research (LTER) Network to assemble a conceptual model of OM dynamics that is consistent with inter-disciplinary perspectives and emphasizes vulnerability of OM pools to disturbance. Guided by this conceptual model, we identified unanticipated patterns and long-term trends in processing and transport of OM emerging from terrestrial, freshwater, wetland, and marine ecosystems. Cross-ecosystem synthesis combined with a survey of researchers revealed several themes: 1) strong effects of climate change on OM dynamics, 2) surprising patterns …

Blue Carbon In South Florida's Mangroves: The Role Of Large Roots And Necromass, Zoë I. Shribman

LSU Master's Theses

Blue carbon sequestration and storage in mangroves largely result from belowground biomass allocation in response to flooded anaerobic soil conditions and nutrient availability. Biomass allocation to belowground roots is a major driver of mangrove soil formation and organic matter accumulation leading to blue carbon storage potential. Belowground biomass sampling in mangroves is labor intensive, limiting data availability on biomass stocks, particularly for large roots (>20 mm diameter) and necromass (dead roots). The mangrove nutrient model (NUMAN) uses mostly literature values to parameterize a soil cohort approach to simulate depth distribution of root mass and organic carbon concentration. We evaluated …

Carbon And Nitrogen Dynamics Of A Lagoon Salt Marsh In Davenport, California, Mark D. Gormley

Dissertations, Theses, and Capstone Projects

Wetlands are complex environments that play a critical role in regulating the global biogeochemical cycle of carbon (C) and nitrogen (N). Wetlands are critical contributors to global climate change and atmospheric chemistry since they store as much as 33% of the world’s soil organic carbon (SOC), release more than 20% of the atmospheric methane (CH₄), and produce nitrous oxide (N₂O), an extremely potent greenhouse gas (GHG). Despite the enormous radiative forcing potential of carbon dioxide (CO₂), CH₄ and N₂O derived from wetlands, uncertainties over the rates of C sequestration and GHG …

Geochronological Implications Of 210Pb And 137Cs Mobility In Cave Guano Deposits, Donald A. Mcfarlane, Joyce Lundberg

International Journal of Speleology

Some recent publications on the paleo- and historical environmental interpretation of bat guano sequences have relied on ²¹⁰Pb and ¹³⁷Cs distribution to establish age-depth models, even when these are at odds with radiocarbon models in the lower parts of the sequence. Here, we present both field and laboratory evidence for the unpredictable mobility of lead and cesium in decomposing bat guano deposits. We suggest that ²¹⁰Pb- and ¹³⁷Cs-based chronologies of bat guano deposits should only be used when independently supported, for example, by a robust radiocarbon age-depth model.

Microbial Activity Responses To Water Stress In Agricultural Soils From Simple And Complex Crop Rotations, Jorg Schnecker, D. Boone Meeden, Francisco Calderon, Michel Cavigelli, R. Michael Lehman, Lisa K. Tiemann, A. Stuart Grandy

Faculty Publications

Increasing climatic pressures such as drought and flooding challenge agricultural systems and their management globally. How agricultural soils respond to soil water extremes will influence biogeochemical cycles of carbon and nitrogen in these systems. We investigated the response of soils from long-term agricultural field sites under varying crop rotational complexity to either drought or flooding stress. Focusing on these contrasting stressors separately, we investigated soil heterotrophic respiration during single and repeated stress cycles in soils from four different sites along a precipitation gradient (Colorado, MAP 421 mm; South Dakota, MAP 580 mm; Michigan, MAP 893 mm; Maryland, MAP 1192 mm); …