David C. Podgorski

David C. Podgorski
University of New Orleans | UNO · Department of Chemistry

Ph.D. Analytical Chemistry
GSD

About

99
Publications
27,702
Reads
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4,284
Citations
Introduction
B.S. Chemistry, Gardner-Webb University, Ph.D. Analytical Chemistry Florida State University (William T. Cooper), Postdoc National Maglab (Alan G. Marshall). Mentored by Robert G.M. Spencer for 5 years as a research scientist at the MagLab/FSU. NSF CAREER Award recipient. Research focuses on the origin, transport, processing, toxicity, and fate of emerging contaminates in aquatic ecosystems.
Additional affiliations
January 2020 - October 2023
University of Alaska Anchorage
Position
  • Affiliate Associate Professor
January 2013 - July 2017
Florida State University
Position
  • Research Faculty
August 2011 - December 2012
The National High Magnetic Field Laboratory (National MagLab)
Position
  • Postdoctoral Associate
Education
August 2007 - August 2011
Florida State University
Field of study
  • Analytical Chemistry
August 2002 - May 2007
Gardner–Webb University
Field of study
  • Chemistry

Publications

Publications (99)
Article
Elevated non-volatile dissolved organic carbon (NVDOC) concentrations in groundwater (GW) monitoring wells under oil-contaminated hydrophobic soils originating from a pipeline rupture at the National Crude Oil Spill & Natural Attenuation Research Site near Bemidji, MN are documented. We hypothesized the elevated NVDOC is comprised of water-soluble...
Article
Previous laboratory studies developed a conceptual model based on elevated non-volatile dissolved organic carbon (NVDOC) concentrations after photodegradation and subsequent dissolution of Macondo oil following the Deepwater Horizon blowout. However, those experiments did not account for the effects of ~1 million gallons of dispersant applied to th...
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Ballast water released from ships into coastal environments has been identified as a mechanism that introduces contaminants of concern into coastal ecosystems. This study investigates the treatment processes employed at a ballast water treatment facility in Valdez, Alaska, that remove hydrocarbons from unsegregated ballast water. Specifically, the...
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Crude oil toxicity to early life stage fish is commonly attributed to polycyclic aromatic hydrocarbons (PAHs). However, it remains unclear how the polar unresolved complex mixture (UCM), which constitutes the bulk of the water-soluble fraction of crude oil, contributes to crude oil toxicity. Additionally, the role of photomodification- induced toxi...
Article
Hydrocarbon (HC) contamination in groundwater (GW) is a widespread environmental issue. Dissolved hydrocarbons in water are commonly utilized as an energy source by natural microbial communities, which can produce water soluble intermediate metabolite compounds, herein referred to as oxygen containing organic compounds (OCOCs), before achieving com...
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Plastics are accumulating on Earth, including at sea. The photodegradation of microplastics floating in seawater produces dissolved organic matter (DOM), indicating that sunlight can photodissolve microplastics at the sea surface. To characterize the chemistry of DOM produced as microplastics photodissolve, three microplastics that occur in surface...
Article
Rare earth elements (REEs) make up a group of unique elements with diverse applications in energy, medicine, and technology. Increasing global demand and limited supplies have led to exploring the economic viability of domestic feedstock extraction from sources such as coal. Little is known about the release of REEs from coal due to the environment...
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Despite the fact that oil chemistry and oil spills have been studied for many years, there are still emerging techniques and unknown processes to be explored. The 2010 Deepwater Horizon oil spill in theGulf of Mexico resulted in a revival of oil spill research across a wide range of fields. These studies provided many new insights, but unanswered q...
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Hydrocarbon oxidation products (HOPs) formed from crude oil and diesel were formed from laboratory simulated spills at four different periods (1, 4, 7, and 10 days) with environmental conditions that mimic those in Cook Inlet, Alaska. Two sets of analyses were performed to identify and characterize the HOPs. The first set of analyses performed was...
Article
Anthropogenic conversion of forests and wetlands to agricultural and urban landcovers impacts dissolved organic matter (DOM) within streams draining these catchments. Research on how landcover conversion impacts DOM molecular level composition and bioavailability, however, is lacking. In the Upper Mississippi River Basin (UMRB), water from low-orde...
Article
The microbial carbon pump (MCP) hypothesis suggests that successive transformation of labile dissolved organic carbon (DOC) by prokaryotes produces refractory DOC (RDOC) and contributes to the long-term stability of the deep ocean DOC reservoir. We tested the MCP by exposing surface water from a deep convective region of the ocean to epipelagic, me...
Article
Photo-oxidized petroleum hydrocarbons are a unique class of water-soluble bioavailable compounds that have gained emerging recognition within toxic regulatory management bodies as an urgent and priority research need in high latitudes. In order to characterize the molecular signatures of photo-oxidized petroleum, bench-scale spills were irradiated...
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Arctic lakes store, modify, and transport large quantities of carbon from terrestrial environments to the atmosphere; however, the spatial and temporal relationships between quantity and composition of dissolved organic matter (DOM) have not been well characterized across broad arctic regions. Moreover, most arctic lake DOM compositions have been e...
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Landcover changes have altered the natural carbon cycle; however, most landcover studies focus on either forest conversion to agriculture or urban, rarely both. We present differences in dissolved organic carbon (DOC) concentrations and dissolved organic matter (DOM) molecular composition within Upper Mississippi River Basin low order streams and r...
Article
Chemical herders and in-situ burning (ISB) are designed to mitigate the effects that oil spills may have on the high latitude marine environment. Little information exists on the water solubilization of petroleum residues stemming from chemically herded ISB and whether these bioavailable compounds have measurable impacts on marine biota. In this ex...
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Climatic changes are transforming northern high‐latitude watersheds as permafrost thaws and vegetation and hydrology shift. These changes have implications for the source and reactivity of riverine dissolved organic matter (DOM), and thus biogeochemical cycling, across northern high‐latitude systems. In this study, we use a latitudinal gradient fro...
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Glaciers and ice sheets cover over 10 % of Earth's land surface area and store a globally significant amount of dissolved organic matter (DOM), which is highly bioavailable when exported to proglacial environments. Recent rapid glacier mass loss is hypothesized to have increased fluxes of DOM from these environments, yet the molecular composition o...
Article
Large rivers are the main arteries for transportation of carbon to the ocean; yet, how hydrology and anthro-pogenic disturbances may change the composition and export of dissolved organic matter along large river continuums is largely unknown. The Yangtze River has a watershed area of 1.80 × 10 6 km 2. It originates from the Qinghai-Tibet Plateau a...
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Permafrost degradation is delivering bioavailable dissolved organic matter (DOM) and inorganic nutrients to surface water networks. While these permafrost subsidies represent a small portion of total fluvial DOM and nutrient fluxes, they could influence food webs and net ecosystem carbon balance via priming or nutrient effects that destabilize back...
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Natural organic matter (NOM) is a complex mixture of biogenic molecules resulting from the deposition and transformation of plant and animal matter. It has long been recognized that NOM plays an important role in many geological, geochemical, and environmental processes. Of particular concern is the fate of NOM in response to a warming climate in e...
Article
Photochemically-released dissolved organic matter (PR-DOM) from resuspended sediments is an understudied flux of dissolved organic carbon (DOC) and nutrients that has the potential to influence estuarine microbial food webs. There is currently limited knowledge on the composition, lability, and biological alterations of this material once released...
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Relationships between dissolved organic matter (DOM) reactivity and chemical composition in a groundwater plume containing petroleum-derived DOM were examined by quantitative and qualitative measurements to determine the source and chemical composition of the compounds that persist downgradient. Samples were collected from a transect down the core...
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Interlaboratory comparison on the determination of the molecular composition of humic substances (HS) was undertaken in the framework of IUPAC project 2016-015-2-600. The analysis was conducted using high resolution mass spectrometry, nominally, Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) with electrospray ionization. Six...
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The origin and reactivity of dissolved organic matter (DOM) have received attention for decades due to the key role DOM plays in global carbon cycling and the ecology of aquatic systems. However, DOM dynamics in river networks remain unresolved, hampered by the lack of data integrating the spatial and temporal dimensions inherent to riverine ecosys...
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Permafrost is an extreme habitat yet it hosts microbial populations that remain active over millennia. Using permafrost collected from a Pleistocene chronosequence (19 to 33 ka), we hypothesized that the functional genetic potential of microbial communities in permafrost would reflect microbial strategies to metabolize permafrost soluble organic ma...
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High‐resolution mass spectrometry (HRMS) has become a vital tool for dissolved organic matter (DOM) characterization. The upward trend in HRMS analysis of DOM presents challenges in data comparison and interpretation among laboratories operating instruments with differing performance and user operating conditions. It is therefore essential that the...
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The Central Siberian Plateau is undergoing rapid climate change that has resulted in increased frequency of forest fires and subsequent alteration of watershed carbon and nutrient dynamics. Across a watershed chronosequence (3 to >100 years since wildfire) we quantified the effects of fire on quantity and composition of dissolved organic matter (DO...
Article
Spilled oil is highly susceptible to sunlight induced transformations, both as films on the surface of water as well as material dissolved or dispersed in the water column. We utilized ultrahigh-resolution mass spectrometry and optical spectroscopy to understand shifts in oil photoproduct distribution as a function of photooxygenation. Oxygenation...
Article
Northern high‐latitude lakes are undergoing climate‐induced changes including shifts in their hydrologic connectivity with terrestrial ecosystems. How this will impact dissolved organic matter (DOM) biogeochemistry remains uncertain. We examined the drivers of DOM composition for lakes in the Yukon Flats Basin in Alaska, an arid region of low relie...
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The standard model for aquatic ecosystems is to link hydrologic connectivity to dissolved organic carbon (DOC) concentration and dissolved organic matter (DOM) composition and, ultimately, reactivity. Studies across effective precipitation gradients have been suggested as models for predicting how carbon cycling will change in Arctic aquatic ecosys...
Article
The flux and composition of carbon (C) from land to rivers represents a critical component of the global C cycle as well as a powerful integrator of landscape‐level processes. In the Congo Basin, an expansive network of streams and rivers transport and cycle terrigenous C sourced from the largest swathe of pristine tropical forest on Earth. Increas...
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Increased permafrost thaw due to climate change in northern high-latitudes has prompted concern over impacts on soil and stream biogeochemistry that affect the fate of dissolved organic carbon (DOC). Few studies to-date have examined the link between molecular composition and biolability of dissolved organic matter (DOM) mobilized from different so...
Article
Shallow lakes are hotspots for carbon processing and important natural sources of methane (CH4) emission. Ebullitive CH4 flux may constitute the overwhelming majority of total CH4 flux, but the episodic nature of ebullition events makes determining both quantity and the controlling factors challenging. Here we used the world's longest running shall...
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Ongoing climate change is making the large pool of organic matter (OM) stored in Arctic permafrost vulnerable to mobilization; thus, garnering a deeper understanding of molecular transformations within the abundant pool of soil OM, specifically humic substances, is crucial. Here we present the first high‐resolution mass‐spectrometry examination of...
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The extraction efficiency of petroleum‐derived dissolved organic matter (DOM) was examined for groundwater samples from an aquifer contaminated with crude oil. Five different types of extraction techniques were investigated to determine which method is best suited for the analysis of potentially toxic petroleum‐derived DOM. The five types were a li...
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Permafrost thaw subjects previously frozen organic carbon (OC) to microbial decomposition, generating the greenhouse gases (GHG) carbon dioxide (CO2) and methane (CH4) and fueling a positive climate feedback. Over one quarter of permafrost OC is stored in deep, ice‐rich Pleistocene‐aged yedoma permafrost deposits. We used a combination of anaerobic...
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In the mostly pristine Congo Basin, agricultural land-use change has intensified in recent years. One potential and understudied consequence of this deforestation and conversion to agriculture is the mobilization and loss of organic matter from soils to rivers as dissolved organic matter. Here, we quantify and characterize dissolved organic matter...
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Agricultural impacts on aquatic ecosystems are well studied; however, most research has focused on temperate regions, whereas the forefront of agricultural expansion is currently in the tropics. At the vanguard of this growth is the boundary between the Amazon and Cerrado biomes in Brazil, driven primarily by expansion of soybean and corn croplands...
Article
In order to examine the molecular-level composition and acute toxicity of petroleum-derived dissolved organic matter (DOMHC) produced via photo-oxidation, a heavy and light oil were irradiated over seawater with simulated sunlight. Increases in dissolved organic carbon (DOC) concentrations as a function of time were associated with changes in DOMHC...
Article
Estuaries support the livelihood of ~ 75% of the world’s population and maintain high primary production in coastal waters, which are often subjected to strong tides and anthropogenic disturbances. There is a paucity of information on how the optical composition and bioavailability of chromophoric dissolved organic matter (CDOM) are influenced by t...
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The Qinghai–Tibet Plateau (QTP) accounts for approximately 70 % of global alpine permafrost and is an area sensitive to climate change. The thawing and mobilization of ice-rich and organic-carbon-rich permafrost impact hydrologic conditions and biogeochemical processes on the QTP. Despite numerous studies of Arctic permafrost, there are no reports...
Article
Fluvial plain lake watersheds are usually highly urbanized and have high concentrations of chromophoric dissolved organic matter (CDOM). CDOM derived from the connecting urban channels usually share strong terrestrial and anthropogenic signals and net inflow runoff (Qnet) to the lake serves as a proxy of residential household sewage input. We inves...
Article
Mountain glaciers store dissolved organic carbon (DOC) that can be exported to river networks and subsequently respired to CO2. Despite this potential importance within the global carbon cycle, the seasonal variability and downstream transport of glacier-derived DOC in mountainous river basins remains largely unknown. To provide novel insight, here...
Article
Inland waters play an important role for the storage of chromophoric dissolved organic matter (CDOM) and outgassing of methane (CH4). However, to date, linkages between the optical dynamics of CDOM and dissolved CH4 levels remain largely unknown. We used multi-year seasonal data series (2012–2014) collected from Lake Taihu and 51 connecting channel...
Article
Wakulla Springs is the largest and deepest freshwater spring on Earth and has exhibited increased chromophoric dissolved organic matter (CDOM) inputs (i.e., browning) in recent decades. To examine the drivers of changing dissolved organic matter at the spring vent, we examined dissolved organic carbon concentrations and dissolved organic matter com...
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Full-text available
The Qinghai-Tibetan Plateau (QTP) accounts for approximately 70 % of global alpine permafrost and is an area sensitive to climate change. The thawing and mobilization of ice and organic carbon-rich permafrost impact hydrologic conditions and biogeochemical processes on the QTP. Despite numerous studies of Arctic permafrost, there are no reports to...
Article
Groundwater samples containing petroleum-derived dissolved organic matter (DOMHC) originating from the north oil body within the National Crude Oil Spill Fate and Natural Attenuation Research Site near Bemidji, MN, USA were analyzed by optical spectroscopic techniques (i.e., absorbance and fluorescence) to assess relationships that can be used to e...
Article
Arctic fluvial networks process, outgas, and transport significant quantities of terrestrial organic carbon (C), particularly dissolved organic carbon (DOC). The proportion of permafrost C in these fluxes, however, is poorly constrained. A primary obstacle to the quantification of permafrost-derived DOC is that it is rapidly respired without leavin...
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Ongoing global temperature rise has caused significant thaw and degradation of permafrost soils on the Qinghai-Tibetan Plateau (QTP). Leaching of organic matter from permafrost soils to aquatic systems is highly complex and difficult to reproduce in a laboratory setting. We collected samples from natural seeps of active and permafrost layers in an...
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Pan-Arctic riverine dissolved organic carbon (DOC) fluxes represent a major transfer of carbon from land-to-ocean and past scaling estimates have been predominantly derived from the six major Arctic rivers. However, smaller watersheds are constrained to northern high-latitude regions and particularly with respect to the Eurasian Arctic have receive...
Article
The link between composition and reactivity of dissolved organic matter (DOM) is central to understanding the role aquatic systems play in the global carbon cycle; yet, unifying concepts driving molecular composition have yet to be established. We characterized 37 DOM isolates from diverse aquatic ecosystems, including their stable and radiocarbon...
Article
We describe complex organic mixture analysis by 21 tesla (T) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Ultrahigh mass-resolving power (m/Δm50% > 2 700 000 at m/z 400) and mass accuracy (80 ppb rms) enable resolution and confident identification of tens of thousands of unique elemental compositions. We demonstrate 2.2-...
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Significance Atmospheric N deposition affects productivity and biodiversity of forests worldwide. However, field-based estimates of atmospheric N deposition for tropical forests are extremely sparse. Our results from a monitoring network in the central Congo Basin exceed current regional N deposition simulations. Ultrahigh-resolution mass spectrome...
Article
The herein described HPLC platform (termed HPLC-3) combines a complex solvent gradient with two electron acceptor columns to provide aromatic ring class (ARC) separation for heavy oils. The separation yields seven major fractions: saturates, mono-aromatics (1-rings), di-aromatics (2-rings), tri-aromatics (3-rings), tetra-aromatics (4-rings), polyar...
Article
This study investigates the effect of photodissolution on the production of dissolved black carbon (DBC) from particulate charcoal and a fire-impacted soil. A soil sample and char sample were collected within the burn vicinity of the 2012 Cache La Poudre River wildfire and irradiated in deionized water with artificial sunlight. Photoexposure of the...
Article
While the biogeochemical forces influencing the weathering of spilled oil have been investigated for decades, the environmental fate and effects of ‘oxyhydrocarbons’ in sand patties deposited on beaches are not well known. We collected sand patties deposited in the swash zone on Gulf of Mexico beaches following the Deepwater Horizon oil spill. When...
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Dissolved organic nitrogen (DON) represents a large percentage of the total nitrogen in rivers and estuaries, and can contribute to coastal eutrophication and hypoxia. This study reports on the composition and bioavailability of DON along the Caloosahatchee River (Florida), a heavily managed system receiving inputs from Lake Okeechobee as well as a...
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In order to characterize the effects of thermal-alteration on water extractable organic matter (WEOM), soil samples were heated in a laboratory at 225, 350, and 500 ˚C. Next, heated and unheated soils were leached, filtered, and analyzed for dissolved organic carbon (DOC) concentration, optical properties, molecular size distribution, molecular com...
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The boreal region stores large amounts of organic carbon (C) in organic-soil horizons, which are vulnerable to destabilization via warming and disturbance. Decomposition of soil organic matter (SOM) contributes to the production and turnover of dissolved organic matter (DOM). While temperature is a primary control on rates of SOM and DOM cycling, l...