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Full-Text Articles in Physical Sciences and Mathematics

Understanding The Role Of The Jet Streams And Gulf Stream Eddies On The Northwest Atlantic Marine Heatwaves, Lydia Rose Duncan Sims Oct 2023

Understanding The Role Of The Jet Streams And Gulf Stream Eddies On The Northwest Atlantic Marine Heatwaves, Lydia Rose Duncan Sims

Theses and Dissertations

The Northwest (NW) Atlantic is one of the fastest warming regions in the global ocean and in the recent decade has experienced several extreme temperature events. These extreme anomalous temperature events are known as Marine Heatwaves (MHWs), which are forced by a variety of physical processes that affect the heat source and sink of the water column. These MHWs have been increasing globally in duration and frequency due to anthropogenic warming, and have increased ecological damage seen in mass mortality events of economically viable species. Within the NW Atlantic, several key processes encourage the formation of MHWs, such as the …


Soil Organic Matter Diagenetic State Informs Boreal Forest Ecosystem Feedbacks To Climate Change, Allison N. Myers-Pigg, Karl Kaiser, Ronald Benner, Susan E. Ziegler Feb 2023

Soil Organic Matter Diagenetic State Informs Boreal Forest Ecosystem Feedbacks To Climate Change, Allison N. Myers-Pigg, Karl Kaiser, Ronald Benner, Susan E. Ziegler

Faculty Publications

The fate of soil organic carbon (SOC) in boreal forests is dependent on the integrative ecosystem response to climate change. For example, boreal forest productivity is often nitrogen (N) limited, and climate warming can enhance N cycling and primary productivity. However, the net effect of this feedback on the SOC reservoir and its longevity with climate change remain unclear due to difficulty in detecting small differences between large and variable carbon (C) fluxes needed to determine net changes in soil reservoirs. The diagenetic state of SOC – resulting from the physicochemical and biological transformations that alter the original biomolecular composition …


Sources And Cycling Of Neodymium And Rare Earth Elements In The Arctic Amerasian Basin And Bering Sea, Brian D. Duggan Oct 2022

Sources And Cycling Of Neodymium And Rare Earth Elements In The Arctic Amerasian Basin And Bering Sea, Brian D. Duggan

Theses and Dissertations

The isotopic composition of dissolved neodymium (143Nd/144Nd, expressed as εNd) behaves quasi-conservatively in the ocean and has been used as a palaeoceanographic tracer of ocean circulation. The εNd value of water masses is acquired—and often altered—during interaction with sediments along the margins; however, the processes involved in seawater εNd acquisition remains poorly characterized and quantified. Here we report the results of 349 Nd isotope and 354 rare earth element (REE) concentration measurements from 27 water column profiles across the Bering shelf and through the Arctic Amerasian Basin collected during U.S. Arctic GEOTRACES cruise HLY1502 (GEOTRACES section …


Arctic Ocean And Subarctic Seas Dynamics In A Changing Climate, Sarah B. Hall Oct 2022

Arctic Ocean And Subarctic Seas Dynamics In A Changing Climate, Sarah B. Hall

Theses and Dissertations

Salinity is the primary determinant of the Arctic Ocean’s vertical density stratification in the upper ocean, which has major implications on the ocean’s physical dynamics alongside a period of rapidly declining sea ice. In recent decades, the Arctic’s freshwater content (FWC) has increased as a result of the accumulation of freshwater source inputs. Additional freshwater exported to the North Atlantic may hinder overturning processes that are vital to the regulation of global climate. This dissertation employs in situ measurements, satellite observations, and ocean model simulations to better understand salinity and freshwater changes in the Arctic Ocean during this changing climate. …


Tropical Cyclone And Ocean-Atmosphere Interactions In The Gulf Of Mexico, Emily Nichole Eley Oct 2022

Tropical Cyclone And Ocean-Atmosphere Interactions In The Gulf Of Mexico, Emily Nichole Eley

Theses and Dissertations

The Gulf of Mexico (GoM) is historically a favorable region for the formation, maintenance and intensification of tropical cyclones that frequently evolve into powerful hurricanes. These natural disasters threaten the basin’s innate habitat and wildlife diversity, and the expansive coastal economies and communities. The dominant ocean circulation feature in the GoM is the Loop Current System (LCS) which includes the Loop Current (LC) and its associated mesoscale eddy field. The LC originates at the Yucatán Channel, loops anticyclonically into the basin, and ends at the Florida Straits; further it produces both anticyclonic and cyclonic eddies. The existence of the LCS …


Destruction Is A Must-See: Coastal Heritage Site Erosion And Public Perception Of Climate Change, Haley Borowy Apr 2022

Destruction Is A Must-See: Coastal Heritage Site Erosion And Public Perception Of Climate Change, Haley Borowy

Senior Theses

Archaeological sites in South Carolina are vanishing. As sea level rise, and therefore coastal erosion, worsen, more sites will disappear. The questions of how erosion at these sites is measured and how the public perceives the effects of climate change have been studied separately, but not together. Here, the intersection of these is discussed, alongside how sites are portrayed affects how the public perceives them, and therefore their importance. Studies on measuring coastal erosion, local news reports, government documents, and public perception of coastal management and sea level rise illuminate how people eventually decide what is worth saving.


What Is Refractory Organic Matter In The Ocean?, Federico Baltar, Xosé A. Alvarez-Salgado, Javier Arístegui, Ronald Benner, Dennis A. Hansell, Gerhard J. Herndl, Christian Lønborg Apr 2021

What Is Refractory Organic Matter In The Ocean?, Federico Baltar, Xosé A. Alvarez-Salgado, Javier Arístegui, Ronald Benner, Dennis A. Hansell, Gerhard J. Herndl, Christian Lønborg

Faculty Publications

About 20% of the organic carbon produced in the sunlit surface ocean is transported into the ocean’s interior as dissolved, suspended and sinking particles to be mineralized and sequestered as dissolved inorganic carbon (DIC), sedimentary particulate organic carbon (POC) or “refractory” dissolved organic carbon (rDOC). Recently, the physical and biological mechanisms associated with the particle pumps have been revisited, suggesting that accepted fluxes might be severely underestimated (Boyd et al., 2019; Buesseler et al., 2020). Perhaps even more poorly understood are the mechanisms driving rDOC production and its potential accumulation in the ocean. On the basis of …


What Is Refractory Organic Matter In The Ocean?, Federico Baltar, Xosé A. Alvarez-Salgado, Javier Arístegui, Ronald Benner, Dennis A. Hansell, Gerhard J. Herndl, Christian Lønborg Apr 2021

What Is Refractory Organic Matter In The Ocean?, Federico Baltar, Xosé A. Alvarez-Salgado, Javier Arístegui, Ronald Benner, Dennis A. Hansell, Gerhard J. Herndl, Christian Lønborg

Faculty Publications

About 20% of the organic carbon produced in the sunlit surface ocean is transported into the ocean’s interior as dissolved, suspended and sinking particles to be mineralized and sequestered as dissolved inorganic carbon (DIC), sedimentary particulate organic carbon (POC) or “refractory” dissolved organic carbon (rDOC). Recently, the physical and biological mechanisms associated with the particle pumps have been revisited, suggesting that accepted fluxes might be severely underestimated (Boyd et al., 2019; Buesseler et al., 2020). Perhaps even more poorly understood are the mechanisms driving rDOC production and its potential accumulation in the ocean. On the basis of …


The Effect Of Barometric Pressure, Temperature, And Precipitation On Preterm Labor In Expecting Women In South Carolina, Allison K. Fletcher Jan 2021

The Effect Of Barometric Pressure, Temperature, And Precipitation On Preterm Labor In Expecting Women In South Carolina, Allison K. Fletcher

Journal of the South Carolina Academy of Science

Each year, approximately 9.9% of infants in the United States are born prematurely at less than 37 weeks of gestation with unidentified causes. From 2014 to 2016, the total preterm birth rate rose 3%, and late preterm birth rates rose almost 4%. One source of preterm labor that has been examined in recent years is its potential correlation with meteorological phenomena, including barometric pressure, temperature, and precipitation. In September of 2019, birth data recording 322 deliveries from two South Carolina hospitals was collected along with weather data on the given dates. The changes in temperature, barometric pressure, and precipitation for …


Molecular Properties Are A Primary Control On The Microbial Utilization Of Dissolved Organic Matter In The Ocean, Yuan Shen, Ronald Benner May 2020

Molecular Properties Are A Primary Control On The Microbial Utilization Of Dissolved Organic Matter In The Ocean, Yuan Shen, Ronald Benner

Faculty Publications

The global ocean sequesters a large amount of reduced carbon in dissolved organic molecules that can persist for centuries to millennia. The persistence of dissolved organic carbon (DOC) in the deep ocean has been attributed to inherently refractory molecules and to low concentrations of molecules, but the relative roles of molecular properties and molecular concentrations remain uncertain. We investigate both of these possibilities using bioas-say experiments with unfiltered seawater collected from five depths (50–1500 m) at the Bermuda Atlantic Time-Series Study site. The microbial utilization of compositionally distinct forms of seawater DOC at in situ and elevated concentrations was determined. …


Importance Of Refractory Ligands And Their Photodegradation For Iron Oceanic Inventories And Cycling, Christel Hassler, Damien Cabanes, Sonia Blanco-Ameijeiras, Sylvia G. Sander, Ronald Benner Dec 2019

Importance Of Refractory Ligands And Their Photodegradation For Iron Oceanic Inventories And Cycling, Christel Hassler, Damien Cabanes, Sonia Blanco-Ameijeiras, Sylvia G. Sander, Ronald Benner

Faculty Publications

Iron is an essential micronutrient that limits primary production in up to 40% of the surface ocean and influences carbon dioxide uptake and climate change. Dissolved iron is mostly associated with loosely characterised organic molecules, called ligands, which define key aspects of the iron cycle such as its residence time, distribution and bioavailability to plankton. Models based on in situ ligand distributions and the behaviour of purified compounds include long-lived ligands in the deep ocean, bioreactive ligands in the surface ocean and photochemical processes as important components of the iron cycle. Herein, we further characterise biologically refractory ligands in dissolved …


The Role Of The Southern Ocean On Global Ocean Circulation And Climate, Brady Scott Ferster Jul 2019

The Role Of The Southern Ocean On Global Ocean Circulation And Climate, Brady Scott Ferster

Theses and Dissertations

The Southern Ocean (SO) is a unique and highly dynamic region with strong temperature and salinity gradients. A comparison between satellite-derived salinity and observations indicates strong differences along coastal boundaries, areas of low temperature, and regions of strong currents. Although differences throughout much of the SO are shown to be negligible, resolution and smoothing in the products create large biases in horizontal gradients and errors in estimating the water cycle. The three-dimensional movement of water within the SO plays an important role in the global Meridional Overturning Circulation (MOC), where the Southern Hemisphere westerlies drive both zonal and meridional transports …


Carbon In The Deep Biosphere: Forms, Fates, And Biogeochemical Cycling, Susan Q. Lang, Magdalena R. Osburn, Andrew D. Steen Jan 2019

Carbon In The Deep Biosphere: Forms, Fates, And Biogeochemical Cycling, Susan Q. Lang, Magdalena R. Osburn, Andrew D. Steen

Faculty Publications

Building on the synthesis of carbon reservoirs in Earth's subsurface, this chapter focuses on the forms, cycling, and fate of the carbon supporting microbial life in the terrestrial and marine subsurface. As the subsurface is estimated to host a vast reservoir of life on Earth, identifying the carbon compounds that life uses for energy and growth is key to understanding ecosystem functioning in the past and at present, and also for extrapolating these findings to the search for life in the universe. This chapter highlights advances in quantifying small carbon compounds, measuring rates of carbon turnover, and the fate of …


Serpentinization: Connecting Geochemistry, Ancient Metabolism And Industrial Hydrogenation, Martina Preiner, Joana C. Xavier, Fliipa L. Sousa, Verena Zimorski, Anna Neubeck, Susan Q. Lang, H. Chris Greenwell, Karl Kleinermanns, Harun Tüysüz, Tom M. Mccollom, Nils G. Holm, William F. Martin Sep 2018

Serpentinization: Connecting Geochemistry, Ancient Metabolism And Industrial Hydrogenation, Martina Preiner, Joana C. Xavier, Fliipa L. Sousa, Verena Zimorski, Anna Neubeck, Susan Q. Lang, H. Chris Greenwell, Karl Kleinermanns, Harun Tüysüz, Tom M. Mccollom, Nils G. Holm, William F. Martin

Faculty Publications

Rock–water–carbon interactions germane to serpentinization in hydrothermal vents have occurred for over 4 billion years, ever since there was liquid water on Earth. Serpentinization converts iron(II) containing minerals and water to magnetite (Fe3O4) plus H2. The hydrogen can generate native metals such as awaruite (Ni3Fe), a common serpentinization product. Awaruite catalyzes the synthesis of methane from H2 and CO2 under hydrothermal conditions. Native iron and nickel catalyze the synthesis of formate, methanol, acetate, and pyruvate—intermediates of the acetyl-CoA pathway, the most ancient pathway of CO2 fixation. Carbon monoxide dehydrogenase …


Evolving Paradigms In Biological Carbon Cycling In The Ocean, Chuanlun Zhang, Hongyue Dang, Farooq Azam, Ronald Benner, Louis Legendre, Uta Passow, Luca Polimene, Carol Robinson, Curtis A. Suttle, Nianzhi Jiao Jul 2018

Evolving Paradigms In Biological Carbon Cycling In The Ocean, Chuanlun Zhang, Hongyue Dang, Farooq Azam, Ronald Benner, Louis Legendre, Uta Passow, Luca Polimene, Carol Robinson, Curtis A. Suttle, Nianzhi Jiao

Faculty Publications

Carbon is a keystone element in global biogeochemical cycles. It plays a fundamental role in biotic and abiotic processes in the ocean, which intertwine to mediate the chemistry and redox status of carbon in the ocean and the atmosphere. The interactions between abiotic and biogenic carbon (e.g. CO2, CaCO3, organic matter) in the ocean are complex, and there is a half-century-old enigma about the existence of a huge reservoir of recalcitrant dissolved organic carbon (RDOC) that equates to the magnitude of the pool of atmospheric CO2. The concepts of the biological carbon pump (BCP) …


An Implementation Strategy To Quantify The Marine Microbial Carbon Pump And Its Sensitivity To Global Change, Carol Robinson, Douglas Wallace, Jung-Ho Hyun, Luca Polimene, Ronald Benner, Yao Zhang, Ruanhong Cai, Rui Zhang, Nianzhi Jiao Jul 2018

An Implementation Strategy To Quantify The Marine Microbial Carbon Pump And Its Sensitivity To Global Change, Carol Robinson, Douglas Wallace, Jung-Ho Hyun, Luca Polimene, Ronald Benner, Yao Zhang, Ruanhong Cai, Rui Zhang, Nianzhi Jiao

Faculty Publications

No abstract provided.


Mixing It Up In The Ocean Carbon Cycle And The Removal Of Refractory Dissolved Organic Carbon, Yuan Shen, Ronald Benner Feb 2018

Mixing It Up In The Ocean Carbon Cycle And The Removal Of Refractory Dissolved Organic Carbon, Yuan Shen, Ronald Benner

Faculty Publications

A large quantity of reduced carbon is sequestered in the ocean as refractory dissolved molecules that persist through several circuits of global overturning circulation. Key aspects of the cycling of refractory dissolved organic carbon (DOC) remain unknown, making it challenging to predict how this large carbon reservoir will respond to climate change. Herein we investigate mechanisms that remove refractory DOC using bioassay experiments with DOC isolated from surface, mesopelagic and deep waters of the Atlantic Ocean. The isolated DOC was refractory to degradation by native microbial communities, even at elevated concentrations. However, when the refractory DOC was introduced to a …


Shelf Cross-Shore Flows Under Storm-Driven Conditions: Role Of Stratification, Shoreline Orientation, And Bathymetry., Xiaodong Wu, Nirnimesh Kumar, George Voulgaris Jan 2018

Shelf Cross-Shore Flows Under Storm-Driven Conditions: Role Of Stratification, Shoreline Orientation, And Bathymetry., Xiaodong Wu, Nirnimesh Kumar, George Voulgaris

Faculty Publications

Numerical simulations are used to study the response of Long Bay, SC (USA), a typical coastal embayment with curved coastline located on the South Atlantic Bight, to realistic, climatologically defined, synoptic storm forcing. Synoptic storms, consisting of cold and warm 25 fronts as well as tropical storms, are used as forcing under both mixed and stratified initial conditions. The analysis focuses on the development of cross-shore shelf circulation and the relative contributions of regionally defined cross-shore winds and alongshore bathymetric variation. The simulation results show that, under stratified conditions, the regionally defined offshore directed wind component promotes upwelling during the …


Biochemical And Structural Controls On The Decomposition Dynamics Of Boreal Upland Forest Moss Tissues, Michael Philben, Sara Butler, Sharon A. Billings, Ronald Benner, Kate A. Edwards, Susan E. Ziegler Jan 2018

Biochemical And Structural Controls On The Decomposition Dynamics Of Boreal Upland Forest Moss Tissues, Michael Philben, Sara Butler, Sharon A. Billings, Ronald Benner, Kate A. Edwards, Susan E. Ziegler

Faculty Publications

Mosses contribute an average of 20 % of boreal upland forest net primary productivity and are frequently observed to degrade slowly compared to vascular plants. If this is caused primarily by the chemical complexity of their tissues, moss decomposition could exhibit high temperature sensitivity (measured as Q10) due to high activation energy, which would imply that soil organic carbon (SOC) stocks derived from moss remains are especially vulnerable to decomposition with warming. Alternatively, the physical structure of the moss cell-wall biochemical matrix could inhibit decomposition, resulting in low decay rates and low temperature sensitivity. We tested these hypotheses by …


A Recent Project Shows That The Microbial Carbon Pump Is A Primary Mechanism Driving Ocean Carbon Uptake, Jing M. Chen, Louis Legendre, Ronald Benner Aug 2017

A Recent Project Shows That The Microbial Carbon Pump Is A Primary Mechanism Driving Ocean Carbon Uptake, Jing M. Chen, Louis Legendre, Ronald Benner

Faculty Publications

No abstract provided.


Strong Linkages Between Surface And Deep-Water Dissolved Organic Matter In The East/Japan Sea, Tae-Hoon Kim, Guebuem Kim, Yuan Shen, Ronald Benner May 2017

Strong Linkages Between Surface And Deep-Water Dissolved Organic Matter In The East/Japan Sea, Tae-Hoon Kim, Guebuem Kim, Yuan Shen, Ronald Benner

Faculty Publications

Vertical and horizontal distributions of total dissolved amino acids (TDAAs), dissolved organic carbon (DOC), and dissolved organic nitrogen (DON) were measured in the East/Japan Sea (EJS). The euphotic zone of this sea is N-limited, and the N : P ratio is ∼ 13 below 200 m depth. Elevated TDAA concentrations (137 ± 34 nM) and DOC-normalized yields (0.8 ± 0.2 % of DOC) were observed in deep waters ( ≥  1000 m) of the EJS and compared with those in the deep North Pacific Ocean. Significantly high TDAA concentrations and yields were observed in a region of deep-water formation, indicating …


Climate Warming Can Accelerate Carbon Fluxes Without Changing Soil Carbon Stocks, Susan E. Ziegler, Ronald Benner, Sharon A. Billings, Kate A. Edwards, Michael Philben, Xinbiao Zhu, Jerome Laganière Feb 2017

Climate Warming Can Accelerate Carbon Fluxes Without Changing Soil Carbon Stocks, Susan E. Ziegler, Ronald Benner, Sharon A. Billings, Kate A. Edwards, Michael Philben, Xinbiao Zhu, Jerome Laganière

Faculty Publications

Climate warming enhances multiple ecosystem C fluxes, but the net impact of changing C fluxes on soil organic carbon (SOC) stocks over decadal to centennial time scales remains unclear. We investigated the effects of climate on C fluxes and soil C stocks using space-for-time substitution along a boreal forest climate gradient encompassing spatially replicated sites at each of three latitudes. All regions had similar SOC concentrations and stocks (5.6 to 6.7 kg C m−2). The three lowest latitude forests exhibited the highest productivity across the transect, with tree biomass:age ratios and litterfall rates 300 and 125% higher than those in …


Sources, Distributions, And Dynamics Of Dissolved Organic Matter In The Canada And Makarov Basins, Yuan Shen, Ronald Benner, Lisa Robbins, Jonathan Wynn Oct 2016

Sources, Distributions, And Dynamics Of Dissolved Organic Matter In The Canada And Makarov Basins, Yuan Shen, Ronald Benner, Lisa Robbins, Jonathan Wynn

Faculty Publications

A comprehensive survey of dissolved organic carbon (DOC) and chromophoric dissolved organic matter (CDOM) was conducted in the Canada and Makarov Basins and adjacent seas during 2010–2012 to investigate the dynamics of dissolved organic matter (DOM) in the Arctic Ocean. Sources and distributions of DOM in polar surface waters were very heterogeneous and closely linked to hydrological conditions. Canada Basin surface waters had relatively low DOC concentrations (69 ± 6 μmol L−1), CDOM absorption (a325: 0.32 ± 0.07 m−1) and CDOM-derived lignin phenols (3 ± 0.4 nmol L−1), and high spectral slope values (S275–295: 31.7 ± …


Sources, Distributions And Dynamics Of Dissolved Organic Matter In The Canada And Makarov Basins, Yuan Shen, Ronald Benner, Lisa L. Robbins, Jonathan G. Wynn Oct 2016

Sources, Distributions And Dynamics Of Dissolved Organic Matter In The Canada And Makarov Basins, Yuan Shen, Ronald Benner, Lisa L. Robbins, Jonathan G. Wynn

Faculty Publications

A comprehensive survey of dissolved organic carbon (DOC) and chromophoric dissolved organic matter (CDOM) was conducted in the Canada and Makarov Basins and adjacent seas during 2010–2012 to investigate the dynamics of dissolved organic matter (DOM) in the Arctic Ocean. Sources and distributions of DOM in polar surface waters were very heterogeneous and closely linked to hydrological conditions. Canada Basin surface waters had relatively low DOC concentrations (69 ± 6 μmol L−1), CDOM absorption (a325: 0.32 ± 0.07 m−1) and CDOM-derived lignin phenols (3 ± 0.4 nmol L−1), and high spectral slope values (S275–295: 31.7 ± …


Biological Hot Spots And The Accumulation Of Marine Dissolved Organic Matter In A Highly Productive Ocean Margin, Yuan Shen, Cédric G. Fichot, Sheng-Kang Liang, Ronald Benner May 2016

Biological Hot Spots And The Accumulation Of Marine Dissolved Organic Matter In A Highly Productive Ocean Margin, Yuan Shen, Cédric G. Fichot, Sheng-Kang Liang, Ronald Benner

Faculty Publications

Concentrations of dissolved organic carbon (DOC) and major biochemicals (amino acids and carbohydrates) were measured during five cruises (2009–2010) to the Louisiana margin in the northern Gulf of Mexico. Concentrations of amino acids and carbohydrates were elevated at mid-salinities and were indicative of plankton production of dissolved organic matter (DOM) in surface waters. Hot spots of two compositionally distinct types of labile DOM were identified based on the relative abundances of amino acids and carbohydrates. Amino acid-rich hot spots occurred sporadically in regions of high phytoplankton biomass and were mostly observed between dusk and dawn, reflecting a grazing source. In …


The Removal Kinetics Of Dissolved Organic Matter And The Optical Clarity Of Groundwater, Francis H. Chapelle, Yuan Shen, Eric W. Strom, Ronald Benner Apr 2016

The Removal Kinetics Of Dissolved Organic Matter And The Optical Clarity Of Groundwater, Francis H. Chapelle, Yuan Shen, Eric W. Strom, Ronald Benner

Faculty Publications

Concentrations of dissolved organic matter (DOM) and ultraviolet/visible light absorbance decrease systematically as groundwater moves through the unsaturated zones overlying aquifers and along flowpaths within aquifers. These changes occur over distances of tens of meters (m) implying rapid removal kinetics of the chromophoric DOM that imparts color to groundwater. A one-compartment input-output model was used to derive a differential equation describing the removal of DOM from the dissolved phase due to the combined effects of biodegradation and sorption. The general solution to the equation was parameterized using a 2-year record of dissolved organic carbon (DOC) concentration changes in groundwater at …


Predicting Dissolved Lignin Phenol Concentrations In The Coastal Ocean From Chromophoric Dissolved Organic Matter (Cdom) Absorption Coefficients, Cédric G. Fichot, Ronald Benner, Karl Kaiser, Yuan Shen, Rainer M. W. Amon, Hiroshi Ogawa, Chua-Jung Lu Feb 2016

Predicting Dissolved Lignin Phenol Concentrations In The Coastal Ocean From Chromophoric Dissolved Organic Matter (Cdom) Absorption Coefficients, Cédric G. Fichot, Ronald Benner, Karl Kaiser, Yuan Shen, Rainer M. W. Amon, Hiroshi Ogawa, Chua-Jung Lu

Faculty Publications

Dissolved lignin is a well-established biomarker of terrigenous dissolved organic matter (DOM) in the ocean, and a chromophoric component of DOM. Although evidence suggests there is a strong linkage between lignin concentrations and chromophoric dissolved organic matter (CDOM) absorption coefficients in coastal waters, the characteristics of this linkage and the existence of a relationship that is applicable across coastal oceans remain unclear. Here, 421 paired measurements of dissolved lignin concentrations (sum of nine lignin phenols) and CDOM absorption coefficients [ag(λ)] were used to examine their relationship along the river-ocean continuum (0–37 salinity) and across contrasting coastal oceans (sub-tropical, temperate, high-latitude). …


Linkages Among Fluorescent Dissolved Organic Matter, Dissolved Amino Acids And Lignin-Derived Phenols In River-Influenced Ocean Margins, Youhei Yamashita, Cédric G. Fichot, Yuan Shen, Rudolf Jaffé, Ronald Benner Nov 2015

Linkages Among Fluorescent Dissolved Organic Matter, Dissolved Amino Acids And Lignin-Derived Phenols In River-Influenced Ocean Margins, Youhei Yamashita, Cédric G. Fichot, Yuan Shen, Rudolf Jaffé, Ronald Benner

Faculty Publications

Excitation emission matrix (EEM) fluorescence spectroscopy coupled with parallel factor analysis (PARAFAC) is commonly used to investigate the dynamics of dissolved organic matter (DOM). However, a lack of direct comparisons with known biomolecules makes it difficult to substantiate the molecular composition of specific fluorescent components. Here, coincident surface-water measurements of EEMs, dissolved lignin, and total dissolved amino acids (TDAA) acquired in the northern Gulf of Mexico were used to investigate the relationships between specific fluorescent components and DOM biomolecules. Two terrestrial humic-like components identified by EEM-PARAFAC using samples obtained from river to offshore waters were strongly linearly correlated with dissolved …


Marine Sequestration Of Carbon In Bacterial Metabolites, Oliver J. Lechtenfeld, Norbert Hertkorn, Yuan Shen, Matthias Witt, Ronald Benner Mar 2015

Marine Sequestration Of Carbon In Bacterial Metabolites, Oliver J. Lechtenfeld, Norbert Hertkorn, Yuan Shen, Matthias Witt, Ronald Benner

Faculty Publications

Linking microbial metabolomics and carbon sequestration in the ocean via refractory organic molecules has been hampered by the chemical complexity of dissolved organic matter (DOM). Here, using bioassay experiments and ultra-high resolution metabolic profiling, we demonstrate that marine bacteria rapidly utilize simple organic molecules and produce exometabolites of remarkable molecular and structural diversity. Bacterial DOM is similar in chemical composition and structural complexity to naturally occurring DOM in sea water. An appreciable fraction of bacterial DOM has molecular and structural properties that are consistent with those of refractory molecules in the ocean, indicating a dominant role for bacteria in shaping …


Pan-Arctic Distributions Of Continental Runoff In The Arctic Ocean, Cédric G. Fichot, Karl Kaiser, Stanford B. Hooker, Rainer M.W. Amon, Marcel Babin, Simon Bélanger, Sally A. Walker, Ronald Benner Jan 2013

Pan-Arctic Distributions Of Continental Runoff In The Arctic Ocean, Cédric G. Fichot, Karl Kaiser, Stanford B. Hooker, Rainer M.W. Amon, Marcel Babin, Simon Bélanger, Sally A. Walker, Ronald Benner

Faculty Publications

Continental runoff is a major source of freshwater, nutrients and terrigenous material to the Arctic Ocean. As such, it influences water column stratification, light attenuation, surface heating, gas exchange, biological productivity and carbon sequestration. Increasing river discharge and thawing permafrost suggest that the impacts of continental runoff on these processes are changing. Here, a new optical proxy was developed and implemented with remote sensing to determine the first pan-Arctic distribution of terrigenous dissolved organic matter (tDOM) and continental runoff in the surface Arctic Ocean. Retrospective analyses revealed connections between the routing of North American runoff and the recent freshening of …