Physical Sciences and Mathematics Commons^™

Flow Injection Determination Of Fluoride For Total Organic Fluorine Analysis, Memona Zulafiqar

Chemistry & Biochemistry Theses

Poly- and perfluoroalkyl substances (PFAS) are anthropogenic chemicals that have gained increasing attention due to their association with a wide range of adverse health effects. These compounds are highly diverse, with approximately 15,000 PFAS reported. Their exceptional environmental stability and strong tendency to bioaccumulate result in environmentally relevant concentrations that typically occur at very low levels, often in the ng L⁻¹ range. This chemical diversity presents a major analytical challenge, as reference standards are available for only a limited number of PFAS. Consequently, conventional targeted analytical methods frequently quantify less than 1% of the total PFAS present, leading to a …

Investigating The Role Of Humic Acid In The Adsorption Mechanics Of Acetaminophen On Potassium Persulfate-Aged Polyethylene Terephthalate (Pet), Andrew Littleton, Maria Danielle Garrett, Phd

SPARK Symposium Presentations

Pharmaceutical contaminants such as acetaminophen (APAP) are showing a rising presence in aquatic environments, where their interactions with microplastics (MPs) can potentially modulate natural degradation mechanisms. Concurrent presence of the two substances has been shown to potentiate increase their individual harmful effects. This study investigates whether oxidative aging and humic-acid surface modification of PET microplastics influence APAP adsorption.

In this study, UV-aging was reproduced using an iron (II)-activated potassium persulfate (Fe(II)-KPS) oxidation system. Aqueous dissolved organic matter (DOM) is simulated using multi-hour exposure to humic acid. The MPs are then removed from the solution to examine adsorption mechanisms. While most …

Asymmetric Synthesis Of The Hiv Protease Inhibitor Tmc-126, A Pmx Antimalarial Protease Inhibitor, And A Putative Covid-19 Inhibitor Using A Highly Stereoselective Glycolate Aldol Addition Reaction Pathway, Kweku Amaning Affram, Austin Carter, April Breede, Alexandra Kimsey, Godson Hemeson, Bader Semakieh, Moses Martinez, Emmanuel Ayim, Joy Odeh, Shawn R. Hitchcock

Faculty Publications – Chemistry

An asymmetric glycolate aldol addition pathway was developed for the synthetic preparation of a series of protease inhibitors based on the hydroxyethylamine structural motif. A single glycolate aldol adduct derived from a highly diastereoselective (≥95:5 d.r.) asymmetric aldol reaction served as the starting point for the synthesis of the inhibitors. The starting material is easily prepared and purified via recrystallization on multigram scales. This work describes the synthesis of the HIV protease inhibitor TMC-126, the Plasmepsin X (PMX) inhibitor 49c for the treatment of malaria, and a computationally derived inhibitor for the 3CLpro of the SARS-CoV-2 from a single common …

Ordo Ab Chao: Crystallographic Disorder As A Window Into Ionic Liquid Structure, Joseph Cooper, Marija Scheuren, Lara I. Teodoro, Christopher M. Butch, Raychell A. Jerdo, Kylie M. Allen, Mariana E. Toner, Matthias Zeller, Arsalan Mirjafari, Patrick C. Hillesheim

Faculty Publications – Chemistry

Despite being intended to resist crystallization, ionic liquids (ILs) quite frequently form solids, albeit with low melting points. The design motifs that lower melting points can leave measurable signatures in the solid state, manifesting as crystallographic disorder, and often give rise to metastable liquid states. While sometimes treated as experimental complications, such features provide a valuable window into the structural origins of IL phase behavior. Herein, we report a crystallographic study of a series of benzylated ILs that crystallize either directly or from long-lived supercooled melts. Single-crystal X-ray diffraction, supported by computational modeling and statistical analyses, provides structural evidence that …

Volatile Organic Compound Analysis Of Humboldt Penguin (Spheniscus Humboldti) Preen Oil: A Pilot Study, Dante E. Rojas, Mitchell M. Mccartney, Eva Borras, Michael O. Eze, Abigail Pietrow, Jennifer J. Valvo, Cristina E. Davis

Chemistry Faculty Research & Creative Works

Avian olfaction has gained prominence in recent decades for its roles in social communication and behavior. In penguins, the chemical characterization of preen oil remains limited. In this exploratory study, we characterized the volatile organic compound (VOC) profile of preen oil from Humboldt Penguins (Spheniscus humboldti). Preen oil from 12 captive individuals was analyzed using headspace sorptive extraction (HSSE) coupled to gas chromatography–mass spectrometry (GC–MS). Chemometric analyses examined variation in VOC profiles by sex, age class, and breeding activity. We detected 54 compounds (20 tentatively identified), including linear alcohols, methyl ketones, carboxylic acids, saturated hydrocarbons, oxygenated and nitrogen-containing organics, prenolipids, …

Soft-Chemical Scalable One-Pot Aqueous-Medium Synthesis Of Na3(Vo)2(Po4)2f-Based Cathodes: Compositional Tuning And Electrochemical Performance In Na- And Li-Ion Batteries, Prashanth Sandineni, Subal Chandra Manna, Sutapa Bhattacharya, Santhoshkumar Sundaramoorthy, Ramesh Deokate, Milad Aghayi-Anaraki, George E. Sterbinsky, Kartik Ghosh, Amitava Choudhury

Chemistry Faculty Research & Creative Works

One of the most important cathode materials for Na-ion batteries, Na₃(VO)₂(PO₄)₂F, and its compositional variants have been synthesized using four different and facile one-step soft chemical routes. The as-synthesized compounds, Na_2.95(VO)₂(PO₄)₂F (I), Na_2.93(VO)₂(PO₄)₂F (II), and Na_2.58(VO)₂(PO₄)₂F (IV), crystallize in the tetragonal crystal system in the P4₂/mnm space group, while Na₃(VO)₂(PO₄)₂F (III) crystallizes in the orthorhombic crystal system in …

Closing The Nitrogen Loop In Groundwater With Biohybrid Technologies, Linjie Zhou, Biao Li, Jianhua Guo, Shelley D. Minteer, Yifeng Zhang

Chemistry Faculty Research & Creative Works

Nitrate in groundwater should be treated as a nitrogen source rather than a contaminant. Biohybrid technologies coupling microbial selectivity with renewable electro(photo)chemical energy offer opportunities to convert nitrate to value-added ammonium, although challenges remain in scalability, microbial stability, material–microbe integration, process engineering, regulatory compliance, and economic feasibility.

Scope Of Microbial Transglutaminase For Site-Specific And Oriented Immobilization Of Native Antibodies From Various Host Species, Emily Beitello, Kwame Osei, Faith E. Breausche, Jon A. Friesen, Jeremy D. Driskell

Faculty Publications – Chemistry

Modification of antibodies to chemically couple labels or immobilization reagents is essential for developing biosensors. Typically, conjugation occurs through chemical methods that leverage reactive amines and thiols on native antibodies; however, this nonspecific approach can interfere with antibody function. Microbial transglutaminase (mTG) is an enzyme that has been used for site-specific conjugation of chemical modifiers to the F_c region of native antibodies, but thus far mTG-mediated conjugation has been limited to production of antibody-drug conjugates with human IgGs. Here, we assessed the scope and versatility of mTG to target IgGs, with the goal of site-specific conjugation to facilitate oriented …

Towards Novel Porphyrinoid Architectures: Synthesis Of Porphyrin Analogues With Two Six-Membered Exocyclic Rings, Amy L. Le, Timothy D. Lash

Faculty Publications – Chemistry

Tripyrranes with terminal ester protective groups were prepared by reacting 7-acetoxy-4,5,6,7-tetrahydroindoles with 3,4-diethylpyrrole in refluxing acetic acid-ethanol. Dibenzyl esters were deprotected by hydrogenolysis over 10% Pd/C and the resulting dicarboxylic acids were condensed with a series of dialdehydes in the presence of trifluoroacetic acid, followed by oxidation with FeCl₃ or DDQ, to give porphyrinoid products with two six-membered exocyclic rings. Reactions with a pyrrole dialdehyde gave porphyrins in 27-30% yield and good yields were also obtained using 2,5-furandicarbaldehyde and 4-hydroxy-2,6-pyridinedicarbaldehyde to prepare oxaporphyrins and oxypyriporphyrins. However, poorer results were noted for thiaporphyrins, benzocarbaporphyrins and oxybenziporphyrins due to their poor …

Exploring The Limitations Of Substrate Scope In Dimethylallyltryptophan Synthases, Evan T. Miller

Theses and Dissertations--Pharmacy

Natural products (NPs), are the largest source of bioactive compounds in Nature, and are essential to the treatment of human disease. Nearly 50% of drugs approved for use from 1981 to 2019 owe some aspect of their development to NPs, either in terms of their structure, pharmacophore, or mechanism of action. However, NPs are difficult to structurally optimize. Chemoenzymatic methods for NP derivatization have been increasingly seen as practical alternatives to traditional synthetic methods. Prenyltransferases (PTs) are involved in the primary and secondary metabolism of plants, bacteria, and fungi, and they are key enzymes in the biosynthesis of many clinically …

Evaluation Of Chromium-Crosslinked Amps-Hpam Copolymer Gels: Effects Of Key Parameters On Gelation Time And Strength, Maryam Sharifi Paroushi, Baojun Bai, Thomas P. Schuman, Yin Zhang, Mingzhen Wei

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Controlling CO₂ channeling in heterogeneous reservoirs remains a major challenge for both enhanced oil recovery (EOR) and secure geological storage. AMPS-HPAM copolymers exhibit high-temperature resistance and brine tolerance compared with conventional HPAM gels, making them well suited for the harsh environments associated with CO₂ injection. Chromium-based crosslinkers (CrAc and CrCl₃) were investigated because sulfonic acid groups in AMPS can coordinate with trivalent chromium ions, enabling dual ionic crosslinking and the formation of a robust gel network. While organic crosslinked AMPS-HPAM gels have been widely studied, the behavior of chromium-crosslinked AMPS-containing systems, particularly their gelation kinetics under …

Climate And Environmental Controls On Forest Soil Organic Matter Cycling, Genevieve Goebel

Dartmouth College Ph.D Dissertations

Climate change factors act on the soil environment in complex ways, known to disturb soil organic carbon (C). Rising global temperatures and alterations to regional precipitation and nitrogen deposition regimes may contribute to the intensification of global change by accelerating the rate of biological decomposition and CO2 efflux to the atmosphere. The magnitude and endurance of the disturbance to soil organic C across landscapes and throughout time that climate change factors may pose to soil C cycling are not comprehensively understood. These knowledge gaps in our field make it challenging to anticipate how soil environments and the vast ecosystems that …

Basis Design For Electronic Structure And Beyond, Weishi Wang

Dartmouth College Ph.D Dissertations

At the intersection of quantum physics, quantum chemistry, and materials science, electronic structure is the study of electrons in solid-state and molecular systems. Electronic-structure computation relies on discretizing the many-electron Hamiltonian with a finite single-particle basis set. However, basis-set construction is conventionally treated as an ad hoc preprocessing step. This thesis develops an expressive and flexible framework for active, system-oriented basis-set design and numerical modeling strategies that treat basis functions as tunable representations to encode electronic ground-state information.

We first introduce a multi-layered, differentiable basis-construction framework that embeds a set of primitive parameters into mixed-contracted Gaussian-type orbitals. We then develop …

Analysis Of Δ¹¹B As A Seawater Ph Proxy: Comparing Ocean Circulation Inverse Model Output With Marine Calcifier Geochemistry, Jesse I. Dong

CMC Senior Theses

Increasing anthropogenic carbon flux into the oceans decreases seawater pH, alters dissolved inorganic carbon speciation, and reduces biogenic calcification. The marine calcifiers— specifically corals and coralline algae—incorporate elements from surrounding seawater into their carbonate structures, which preserve past records of ocean carbon chemistry. In particular, boron in biogenic carbonate is a potentially valuable proxy for historical ocean pH across human timescales. Within seawater, boron primarily exists as boric acid B(OH)3 and borate ions B(OH)4 - , where higher pH favors the formation of borate ions. Borate ions preferentially incorporate the heavier ¹¹B isotope over 10B. On the other hand, if …

Investigations Toward A Unified Reaction Pathway Of Thermal And Tbsotf-Mediated Oxidopyrylium-Alkene (5 + 2) Cycloadditions, Adam J. Youman, Samantha N. Rokey, Wentao Guo, Jacob P. Grabowski, Susanna N. Angles, Jacob J. Bulandr, Qing Sun, John R. Goodell, Dean J. Tantillo, T. Andrew Mitchell

Faculty Publications – Chemistry

Oxidopyrylium-based (5 + 2) cycloadditions are crucial reactions to construct seven-membered carbocycles containing an ether bridge (i.e. oxabicyclo[3.2.1]octanes). Intramolecular silyloxypyrone-based (5 + 2) cycloadditions were investigated and revealed several features: (1) the TBDPS thermal process proceeds via a zwitterionic oxidopyrylium intermediate similar to previously reported TBS variants; (2) the TBSOTf-mediated reaction proceeds through a cationic oxidopyrylium intermediate; (3) quantum chemical calculations predict a stepwise process for an electron-rich dipolarophile for each set of conditions. The thermal silyloxypyrone-based (5 + 2) cycloadditions were extremely dependent on the nature of the dipolarophile and the silyl transfer group. The TBDPS enhances the …

Nicotine, Bdnf, And Ꞵ-Adrenergic Ligand Receptors Regulate Soluble E-Cadherin Signaling In Non-Small Cell Long Cancer, Stuti Goel

Senior Honors Theses and Projects

E-cadherin is a protein that normally helps cells adhere to each other. Sometimes, part of this protein is cleaved off and released outside the cell as soluble E-cadherin (sE-cad). When this happens, there is less E-cadherin left on the cell surface. Enzymes called matrix metalloproteases, especially MMP9, are responsible for this cleavage. In this study, we investigated E-cadherin in two non-small cell lung cancer cell lines, A549 and H1299. We found that treating these cells with brain-derived neurotrophic factor (BDNF), nicotine, or epinephrine increased the amount of MMP9 released into the surrounding media. When the cells were treated with propranolol, …

Rapid Classification And Quality Assessment Of Citrus Essential Oils Via Machine-Learning-Assisted Raman Spectroscopy, Yong Xuan Hong, Jia Wei Tang, Jie Chen, Yun Yun Xie, Zhang Wen Ma, Qing Hua Liu, Liang Wang

Research outputs 2022 to 2026

Citrus essential oils (EOs) require accurate identification and assessment to ensure authenticity and consistency. However, conventional techniques such as gas chromatography (GC) and mass spectrometry (MS) are time-consuming and expensive, highlighting the need for novel analytical methods. This study proposes an approach for EOs detection using Raman spectroscopy (RS) combined with machine learning (ML) algorithms. Six citrus EOs underwent an evaporation experiment, with Raman spectra collected at five time points and GC-MS was used to analyze compositional changes at the starting and ending points of evaporation as a standard reference. Five ML algorithms were developed to identify differences among EOs …

A Bioinspired Approach For Adaptive Solid-Solid Phase Change Material Coatings With Optimized Surface Features For Passive Thermal Regulation, Rajae Bousselham, Zhiying Xiao, Mingjiang Tao, Sergio Granados-Focil, Adriana Hera, Steven Van Dessel

Chemistry

The necessity to reduce global energy consumption calls for innovative strategies in building thermal management. Passive thermal regulation, particularly through bio-inspired designs, offers a promising avenue by mimicking nature's efficient control of optical properties. This research introduces a novel, climate-responsive coating that integrates optimized bio-inspired surface features with a solid-solid phase change material (SS-PCM) to dynamically manage solar absorptivity without adding additional thickness, enabling both heating and cooling as needed. Drawing on the photonic architectures of the Saharan silver ant and Morpho Didius butterfly, we employed a modeling and multi-objective optimization framework to tailor these surface features. Simulations reveal that …

Theoretical Study Of Long-Range Molecular Interactions, Adrian Luis Batista-Planas

Doctoral Dissertations

Describing intermolecular forces is fundamental to modeling and predicting the behavior of molecular systems. In particular, long-range molecular interactions—with electrostatic, induction, and dispersion as main components—play a critical role, especially for low-temperature and low-density regimes. Long-range interactions are often described through perturbation theory, representing the electronic charge distribution via multipolar series of the moments and polarizability tensors corresponding to each molecule. However, while the theory is well-established, obtaining the resulting analytical expressions (and their practical implementation) constitutes a highly complex and system-dependent task. To address this challenge, we developed Long-Range-Fit (LRF), an interactive and user-friendly software package designed to automate …

Redox-Mediator Enhanced Electrochemiluminescence Under Non-Aqueous Conditions, Steven J. Blom, Fazeleh Mesgari, El M.S. Martin, Egan H. Doeven, David J. Hayne, Timothy U. Connell, Peter J. Barnard, Narges Saeedizadeh, Seyed Mohammad Jafar Jalali, Paul S. Francis

Research outputs 2022 to 2026

The introduction of small-molecule redox mediators into aqueous co-reactant electrochemiluminescence (ECL) systems has emerged as an effective strategy to increase signal intensity. Herein, we investigate the influence of a series of neutral iridium(iii) complexes (Ir(pmi)3, Ir(ppy)3, Ir(ppz)3 and Ir(ppy)2(acac)) as redox mediators for co-reactant ECL in acetonitrile. Using [Ru(bpy)3]²⁺ as a benchmark luminophore and tri-n-propylamine (TPrA) as a co-reactant, the redox mediators elicit similar effects in this solvent to those of their sulfonated [Ir(sppy)3]³⁻ and [Ir(sppz)3]³⁻ analogues under aqueous conditions. The Ir(ppz)3 complex was most effective; at a concentration of 100 µM it produced an 11-fold increase …

Design, Synthesis, And Characterization Of Phosphonate-Functionalized Diimide Ligands For Metal-Organic Framework Construction, Kenya Rosas, Jonathan Uribe

Posters - 2026

• Metal–organic frameworks (MOFs) are solid, porous materials composed of metalions reacted with organic linkers

• MOFs are customizable through variations in their metal ions, organic linkers, and the functional groups of the organic linker all yielding a structure with different properties

• MOFs have a variety of applications, ranging from storage and catalysis to drug delivery

• The synthesis and characterization of four phosphonate-based diimide ligands:
  • N,N´-bis(phosphonomethyl)-pyromellitimide (PPMI).
  • N,N´-bis(phosphonobenzyl)-pyromellitimide (PPMI-Ph).
  • N,N´-bis(phosphonomethyl)-3,3′,4,4′-biphenylenediimide (PBDI).
  • N,N´-bis(phosphonobenzyl)-3,3′,4,4′-biphenylenediimide (PBDI-Ph).

• These ligands were then coordinated with zinc or copper metal ions to make MOFs.

De Novo Protein Binding To Zinc Oxide Through Biomineralization Pathways, Jean-Mark A. Francis

Theses and Dissertations

De novo proteins are structurally distinct from proteins found in nature and thus capable of having their amino acid sequence modified to accomplish tasks such as increasing protein-nanoparticle binding without unfolding or decomposing. Zinc Oxide nanoparticles are functionally distinct from their bulk counterparts and are widely used as semiconductors in a variety of fields such as medicine and agriculture. With demand for these nanoparticles increasing, environmentally sustainable methods of Zinc Oxide nanoparticle synthesis are being investigated as an eco-friendly alternative to currently utilized but environmentally hazardous chemical and physical techniques. This research investigates the binding characteristics between Zinc Oxide nanoparticles …

Net Carbonyl Ene Reactions Of Olefins With Aldehydes, Alexandra Mock

Honors Theses

Aldehydes and olefins react in the presence of base and TMSOTf to yield homoallylic alcohols. In this net ene reaction, TMSOTf acts as a Lewis acid to activate the aldehyde, leading to a strong oxygen-silicon bond that acts as a driving force in the reaction. In the proposed mechanism, the α-methylstyrene attacks the carbonyl carbon of the TMSOTf-activated aldehyde to produce a carbocationic intermediate. Elimination using a relatively bulky base (2,6-lutidine) provides the homoallylic alcohol. This reaction has proven robust in terms of the aldehyde and olefin scope.

Biochemical Investigations Of F420-Dependent Glucose-6-Phosphate Dehydrogenase From Cryptosporangium Arvum, Sarah T. Al-Noubani

2026 Spring Honors Capstones Projects

F₄₂₀-dependent glucose-6-phosphate dehydrogenase (FGD) catalyzes the conversion of glucose-6-phosphate to 6-phosphogluconolactone using the deazaflavin, Cofactor F₄₂₀. FGD from Mycobacterium tuberculosis has been investigated due to its health relevance to prodrug activation. More recently, FGD from Cryptosporangium arvum (Cryar- FGD) has been investigated due to its broader substrate specificity toward multiple sugar phosphates. Kinetic and NMR studies have shown that Cryar-FGD has dual catalytic activity as a dehydrogenase and isomerase. Further investigations are being conducted on Cryar-FGD to characterize key residues involved in catalysis.

To investigate the catalytically active residues of Cryar-FGD, …

Assessing Dissolved Organic Matter Sources And Dynamics In Urban Stormwater: Implications For Greenhouse Gases, Harper W. Schmalz

Theses and Dissertations (Comprehensive)

Stormwater management ponds (SWMPs) are important aspects of land-use planning and increasingly recognized as active sites of biogeochemical processing that influence carbon cycling; however, little research has investigated the controls on dissolved organic and dissolved inorganic carbon (DOC and DIC) within these systems. This thesis examined the processing and transformations of dissolved carbon between three compartments to support the development of a greenhouse gas (GHG) box-model for urban stormwater ponds, including SWMP sediment, surface water, and vegetation. The objective of this thesis was to assess the biogeochemical processes that govern the rate and transformation of DOC and DIC between these …

Modular Synthesis Of Conjugated Aromatic Systems Via Palladium-Catalyzed Cross-Coupling Reactions, Joden Russell Robinson

Dissertations, Master's Theses and Master's Reports

This thesis describes the development of a modular synthetic route to extended conjugated aromatic systems through iterative palladium-catalyzed Sonogashira crosscoupling reactions. The work was motivated by the challenge of preparing a discrete conjugated molecule in a controlled manner. The synthetic strategy used complementary protected alkyne functionalities that could be selectively activated. This enabled sequential deprotection and coupling reactions to predictably extend the molecular scaffold. Using this approach, a series of conjugated intermediates was prepared and exponentially extended. Spectroscopic characterization by NMR and mass spectrometry supported the structures of the isolated products and the success of the iterative elongation strategy. Overall, …

Multiscale Modeling Of The Thermomechanical Behavior Of Polymeric And Molecular Organic Semiconductors, Kehinde H. Fagbohungbe

University of Kentucky Doctoral Dissertations

Organic semiconductors, derived from π-conjugated polymers and molecules, enable the development of deformable, stretchable and flexible electronics due to their tunable redox, optical, electronic and mechanical properties. However, an informed understanding of how multi-scale morphological characteristics of the polymeric and molecular semiconductors influence bulk properties that contribute to electronic and optical performance, especially under operational thermal and mechanical stresses, remains incomplete. This lack of understanding poses a challenge to scalability and commercialization of organic electronics. This dissertation develops and deploys computational modeling approaches, particularly atomistic molecular dynamics (MD) simulations, to investigate the multiscale morphological behavior of these synthetic semiconducting materials …

Synthesis And Characterization Of Succinate Dehydrogenase Inhibitors H2/Z14 And C6/Z96 In Order To Combat Small Cell Lung Cancer, Lauren M. Graves

Honors Undergraduate Theses

The use of ubiquinone inhibitors to combat cancer is a recent development in medicinal science and procedures to efficiently synthesize these drugs remain limited. C6/Z96 and H2/Z14, two succinate dehydrogenase inhibitors, have been previously tested in vitro against NSCLC with positive results. Their similarity to ubiquinone is what makes them a strong candidate for a succinate dehydrogenase inhibitor at the ubiquinone binding site. The heterocyclic scaffolds and substituents are proposed to bind strongly through a combination of electronics, hydrogen-bonding, and fit, allowing them to bind well and prove to be more favorable than ubiquinone when competing for the Q-site. By …

Testing The Limits Of Provenance Analysis From Basaltic Fluvial Sediment Near Sandvatn, Iceland, As A Mars Analog, Audrey R. Putnam, Kirsten L. Siebach, Michael T. Thorpe, Valerie M. Tu, Elizabeth B. Rampe, Candice C. Bedford, Gelu Costin, Joseph J. Tamborski

OES Faculty Publications

Detrital sediments that accumulate downstream and are preserved in sedimentary rocks can allow characterization of geologic formations that are inaccessible for spatial or temporal reasons. However, mixing, sorting, and alteration of sediment during transport may complicate reconstruction of protolith characteristics. We test the preservation of three key provenance signals in coarse fluvial sand at a Mars analog watershed in Iceland to determine whether detrital sediments capture (a) watershed magmatic chemical variation, (b) textural indicators of lava-water interaction during eruption and cooling, and (c) hydrothermal alteration. Specifically, we tested whether diagnostic variations in rock mineralogy, chemistry, and texture can be recovered …

Characterization Of Phytoplankton-Excreted Metabolites Mediating Carbon Flux Through The Surface Ocean, Yuting Zhu, Hanna S. Anderson, Eli Salcedo, Samuel E. Miller, Krista Longnecker, Melissa C. Kido Soule, Sheean T. Haley, Gretchen J. Swarr, Rogier Braakman, Sonya T. Dyhrman, Elizabeth B. Kujawinski

Chemistry & Biochemistry Faculty Publications

The marine labile dissolved organic carbon (DOC) pool is a dynamic reservoir of thousands of molecules that cycles approximately one-quarter of Earth’s primary production within days to weeks. After excretion by phytoplankton and other microbes, metabolites are rapidly consumed, resulting in low standing concentrations (picomolar to low nanomolar). Despite the decades-long search for labile DOC sources and molecular identities, marine phytoplankton exometabolomes are not well characterized, largely due to difficulties in measuring small polar molecules in saline water. Here, we profiled the exometabolomes of six axenic phytoplankton species representing key functional groups including a diatom (Thalassiosira pseudonana CCMP1335), a …