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Full-Text Articles in Physical Sciences and Mathematics

Potential Virus-Mediated Nitrogen Cycling In Oxygen-Depleted Oceanic Waters, M. Consuelo Gazitúa, Dean R. Vik, Simon Roux, Ann C. Gregory, Benjamin Bolduc, Brittany Widner, Margaret R. Mulholland, Steven J. Hallam, Osvaldo Ulloa, Matthew B. Sullivan Nov 2020

Potential Virus-Mediated Nitrogen Cycling In Oxygen-Depleted Oceanic Waters, M. Consuelo Gazitúa, Dean R. Vik, Simon Roux, Ann C. Gregory, Benjamin Bolduc, Brittany Widner, Margaret R. Mulholland, Steven J. Hallam, Osvaldo Ulloa, Matthew B. Sullivan

OES Faculty Publications

Viruses play an important role in the ecology and biogeochemistry of marine ecosystems. Beyond mortality and gene transfer, viruses can reprogram microbial metabolism during infection by expressing auxiliary metabolic genes (AMGs) involved in photosynthesis, central carbon metabolism, and nutrient cycling. While previous studies have focused on AMG diversity in the sunlit and dark ocean, less is known about the role of viruses in shaping metabolic networks along redox gradients associated with marine oxygen minimum zones (OMZs). Here, we analyzed relatively quantitative viral metagenomic datasets that profiled the oxygen gradient across Eastern Tropical South Pacific (ETSP) OMZ waters, assessing whether OMZ …


Under-Ice Phytoplankton Blooms: Shedding Light On The "Invisible" Part Of Arctic Primary Production, Mathieu Ardyna, C. J. Mundy, Nicolas Mayot, Lisa C. Matthes, Laurent Oziel, Christopher Horvat, Eva Leu, Philipp Assmy, Victoria Hill, Patricia A. Matrai, Matthew Gale, Igor A. Melnikov, Kevin R. Arrigo Nov 2020

Under-Ice Phytoplankton Blooms: Shedding Light On The "Invisible" Part Of Arctic Primary Production, Mathieu Ardyna, C. J. Mundy, Nicolas Mayot, Lisa C. Matthes, Laurent Oziel, Christopher Horvat, Eva Leu, Philipp Assmy, Victoria Hill, Patricia A. Matrai, Matthew Gale, Igor A. Melnikov, Kevin R. Arrigo

OES Faculty Publications

The growth of phytoplankton at high latitudes was generally thought to begin in open waters of the marginal ice zone once the highly reflective sea ice retreats in spring, solar elevation increases, and surface waters become stratified by the addition of sea-ice melt water. In fact, virtually all recent large-scale estimates of primary production in the Arctic Ocean (AO) assume that phytoplankton production in the water column under sea ice is negligible. However, over the past two decades, an emerging literature showing significant under-ice phytoplankton production on a pan-Arctic scale has challenged our paradigms of Arctic phytoplankton ecology and phenology. …


Sea-Ice Production And Air/Ice/Ocean/Biogeochemistry Interactions In The Ross Sea During The Pipers 2017 Autumn Field Campaign, S. F. Ackley, S. Stammerjohn, T. Maksym, M. Smith, J. Cassano, P. Guest, J.-L. Tison, B. Delille, B. Loose, Peter N. Sedwick, L. Depace, L. Roach, J. Parno Sep 2020

Sea-Ice Production And Air/Ice/Ocean/Biogeochemistry Interactions In The Ross Sea During The Pipers 2017 Autumn Field Campaign, S. F. Ackley, S. Stammerjohn, T. Maksym, M. Smith, J. Cassano, P. Guest, J.-L. Tison, B. Delille, B. Loose, Peter N. Sedwick, L. Depace, L. Roach, J. Parno

OES Faculty Publications

The Ross Sea is known for showing the greatest sea-ice increase, as observed globally, particularly from 1979 to 2015. However, corresponding changes in sea-ice thickness and production in the Ross Sea are not known, nor how these changes have impacted water masses, carbon fluxes, biogeochemical processes and availability of micronutrients. The PIPERS project sought to address these questions during an autumn ship campaign in 2017 and two spring airborne campaigns in 2016 and 2017. PIPERS used a multidisciplinary approach of manned and autonomous platforms to study the coupled air/ice/ocean/biogeochemical interactions during autumn and related those to spring conditions. Unexpectedly, the …


An Introduction To “Microbial Biogeochemistry: A Special Issue Of Aquatic Geochemistry Honoring Mark Hines”, W. Berry Lyons, David J. Burdige May 2020

An Introduction To “Microbial Biogeochemistry: A Special Issue Of Aquatic Geochemistry Honoring Mark Hines”, W. Berry Lyons, David J. Burdige

OES Faculty Publications

(First paragraph) This issue of Aquatic Geochemistry is dedicated to the memory of Dr. Mark E. Hines (Fig. 1) and his contributions to the fields of microbial biogeochemistry and aquatic geochemistry. Mark passed away in March of 2018, and through his career as a researcher, teacher, mentor, colleague, and university administrator, he greatly influenced the lives of all around him. We hope that this volume will serve not only as a memory of Mark, but also as a way to recognize his significant influences and major contributions in the fields of carbon, sulfur, and trace element biogeochemistry.


A Critical Review Of The 15N2 Tracer Method To Measure Diazotrophic Production In Pelagic Ecosystems, Angelicque E. White, Julie Granger, Corday Seldon, Mary R. Gradoville, Lindsey Potts, Annie Bourbonnais, Robinson W. Fulweiler, Angela N. Knapp, Wiebke Mohr, Pia H. Moisander, Craig R. Tobias, Mathieu Caffin, Samuel T. Wilson, Mar Benavides, Sophie Bonnet, Margaret R. Mulholland, Bonnie X. Chang Apr 2020

A Critical Review Of The 15N2 Tracer Method To Measure Diazotrophic Production In Pelagic Ecosystems, Angelicque E. White, Julie Granger, Corday Seldon, Mary R. Gradoville, Lindsey Potts, Annie Bourbonnais, Robinson W. Fulweiler, Angela N. Knapp, Wiebke Mohr, Pia H. Moisander, Craig R. Tobias, Mathieu Caffin, Samuel T. Wilson, Mar Benavides, Sophie Bonnet, Margaret R. Mulholland, Bonnie X. Chang

OES Faculty Publications

Dinitrogen (N2) fixation is an important source of biologically reactive nitrogen (N) to the global ocean. The magnitude of this flux, however, remains uncertain, in part because N2 fixation rates have been estimated following divergent protocols and because associated levels of uncertainty are seldom reported—confounding comparison and extrapolation of rate measurements. A growing number of reports of relatively low but potentially significant rates of N2 fixation in regions such as oxygen minimum zones, the mesopelagic water column of the tropical and subtropical oceans, and polar waters further highlights the need for standardized methodological protocols for measurements …


Surface Elevation And Sedimentation Dynamics In The Ganges-Brahmaputra Tidal Delta Plain, Bangladesh: Evidence For Mangrove Adaptation To Human-Induced Tidal Amplification, Edwin J. Bomer, Carol A. Wilson, Richard Hale, Abu Naser Mohsin Hossain, F.M. Arifur Rahman Apr 2020

Surface Elevation And Sedimentation Dynamics In The Ganges-Brahmaputra Tidal Delta Plain, Bangladesh: Evidence For Mangrove Adaptation To Human-Induced Tidal Amplification, Edwin J. Bomer, Carol A. Wilson, Richard Hale, Abu Naser Mohsin Hossain, F.M. Arifur Rahman

OES Faculty Publications

In the Ganges-Brahmaputra (G-B) delta, periodic flooding of the land surface during the tidal cycle coupled with enormous sediment delivery during the monsoon promotes sediment accretion and surface elevation gain through time. However, over the past several decades, widespread embankment (“polder”) construction in the GB tidal delta plain has led to numerous environmental disturbances, including channel siltation and tide range amplification. While previous research indicates that rates of sediment accretion are relatively high in the G-B tidal delta plain, it remains unclear if and how surface elevation is maintaining pace with relative sea-level rise (RSLR) in this region. In this …


Marine Carbonyl Sulfide (Ocs) And Carbon Disulfide (Cs2): A Compilation Of Measurements In Seawater And The Marine Boundary Layer, Sinikka T. Lennartz, Christa A. Marandino, Marc Von Hobe, Meinrat O. Andreae, Kazushi Aranami, Elliot Atlas, Max Berkelhammer, Heinz Bingemer, Dennis Booge, Gregory A. Cutter, Pau Cortes, Stefanie Kremser, Cliff S. Law, Andrew Marriner, Rafel Simó, Birgit Quack, Günther Uher, Huixiang Xie, Xiaobin Xu Mar 2020

Marine Carbonyl Sulfide (Ocs) And Carbon Disulfide (Cs2): A Compilation Of Measurements In Seawater And The Marine Boundary Layer, Sinikka T. Lennartz, Christa A. Marandino, Marc Von Hobe, Meinrat O. Andreae, Kazushi Aranami, Elliot Atlas, Max Berkelhammer, Heinz Bingemer, Dennis Booge, Gregory A. Cutter, Pau Cortes, Stefanie Kremser, Cliff S. Law, Andrew Marriner, Rafel Simó, Birgit Quack, Günther Uher, Huixiang Xie, Xiaobin Xu

OES Faculty Publications

Carbonyl sulfide (OCS) and carbon disulfide (CS2) are volatile sulfur gases that are naturally formed in seawater and exchanged with the atmosphere. OCS is the most abundant sulfur gas in the atmosphere, and CS2 is its most important precursor. They have attracted increased interest due to their direct (OCS) or indirect (CS2 via oxidation to OCS) contribution to the stratospheric sulfate aerosol layer. Furthermore, OCS serves as a proxy to constrain terrestrial CO2uptake by vegetation. Oceanic emissions of both gases contribute a major part to their atmospheric concentration. Here we present a database of …


Organic Sulfur: A Spatially Variable And Understudied Component Of Marine Organic Matter, Krista Longnecker, Lisa Oswald, Melissa C. Kido Soule, Gregory A. Cutter, Elizabeth B. Kujawinski Feb 2020

Organic Sulfur: A Spatially Variable And Understudied Component Of Marine Organic Matter, Krista Longnecker, Lisa Oswald, Melissa C. Kido Soule, Gregory A. Cutter, Elizabeth B. Kujawinski

OES Faculty Publications

Sulfur (S) is a major heteroatom in organic matter. This project evaluated spatial variability in the concentration and molecular-level composition of organic sulfur along gradients of depth and latitude. We measured the concentration of total organic sulfur (TOS) directly from whole seawater. Our data reveal high variability in organic sulfur, relative to established variability in total organic carbon or nitrogen. The deep ocean contained significant amounts of organic sulfur, and the concentration of TOS in North Atlantic Deep Water (NADW) decreased with increasing age while total organic carbon remained stable. Analysis of dissolved organic matter extracts by ultrahigh resolution mass …


Hydrothermal Activity And Seismicity At Teahitia Seamount: Reactivation Of The Society Islands Hotspot?, Christopher R. German, Joseph A. Resing, Guangyu Xu, Isobel A. Yeo, Sharon L. Walker, Colin W. Devey, James W. Moffett, Gregory A. Cutter, Olivier Hyvernaud, Dominique Reymond Jan 2020

Hydrothermal Activity And Seismicity At Teahitia Seamount: Reactivation Of The Society Islands Hotspot?, Christopher R. German, Joseph A. Resing, Guangyu Xu, Isobel A. Yeo, Sharon L. Walker, Colin W. Devey, James W. Moffett, Gregory A. Cutter, Olivier Hyvernaud, Dominique Reymond

OES Faculty Publications

Along mid-ocean ridges, submarine venting has been found at all spreading rates and in every ocean basin. By contrast, intraplate hydrothermal activity has only been reported from five locations, worldwide. Here we extend the time series at one of those sites, Teahitia Seamount, which was first shown to be hydrothermally active in 1983 but had not been revisited since 1999. Previously, submersible investigations had led to the discovery of low-temperature (≤30°C) venting associated with the summit of Teahitia Seamount at ≤1500 m. In December 2013 we returned to the same site at the culmination of the US GEOTRACES Eastern South …


Abiotic Formation Of Dissolved Organic Sulfur In Anoxic Sediments Of Santa Barbara Basin, Hussain A. Abdulla, David J. Burdige, Tomoko Komada Jan 2020

Abiotic Formation Of Dissolved Organic Sulfur In Anoxic Sediments Of Santa Barbara Basin, Hussain A. Abdulla, David J. Burdige, Tomoko Komada

OES Faculty Publications

Sulfurization has been found to enhance organic matter preservation and petroleum formation in marine sediments. However, we do not yet have a comprehensive understanding of sulfurization mechanisms. In this study, we investigated several possible mechanisms of dissolved organic sulfur (DOS) formation in the top 4.5 m of anoxic sediments of Santa Barbara Basin (SBB), California Borderland. Using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS), we identified chemical formulas of potential dissolved organic matter (DOM) precursors to these DOS compounds. We also examined how the formulas of abiotically formed DOS changed as a function of depth across a major redox …


An Oceanographic Perspective On Early Human Migrations To The Americas, Thomas C. Royer, Bruce Finney Jan 2020

An Oceanographic Perspective On Early Human Migrations To The Americas, Thomas C. Royer, Bruce Finney

OES Faculty Publications

Early migrants to the Americas were likely seaworthy. Many archaeologists now agree that the first humans who traveled to the Americas more than 15,000 years before present (yr BP) used a coastal North Pacific route. Their initial migration was from northeastern Asia to Beringia where they settled for thousands to more than ten thousand years. Oceanographic conditions during the Last Glacial Maximum (18,000-24,000 yr BP) would have enhanced their boat journeys along the route from Beringia to the Pacific Northwest because the influx of freshwater that drives the opposing Alaska Coastal Current was small, global sea level was at least …


Microplastic Fragment And Fiber Contamination Of Beach Sediments From Selected Sites In Virginia And North Carolina, Usa, Gabrielle Z. Dodson, A. Katrina Shotorban, Patrick G. Hatcher, Derek Waggoner, Sutapa Ghosal, Nora Noffke Jan 2020

Microplastic Fragment And Fiber Contamination Of Beach Sediments From Selected Sites In Virginia And North Carolina, Usa, Gabrielle Z. Dodson, A. Katrina Shotorban, Patrick G. Hatcher, Derek Waggoner, Sutapa Ghosal, Nora Noffke

OES Faculty Publications

Microplastic particles (<5 >mm) constitute a growing pollution problem within coastal environments. This study investigated the microplastic presence of estuarine and barrier island beaches in the states of Virginia and North Carolina, USA. Seventeen sediment cores were collected at four study sites and initially tested for microplastic presence by pyrolysis-gas chromatography–mass spectrometry. For the extraction, microplastic particles were first separated from the sediment using a high-density cesium chloride solution (1.88 g/mL). In a second step, an oil extraction collected the remaining microplastic particles of higher densities. Under the light microscope, the extracted microplastic particles were classified based on their morphologies …


Quantifying Seagrass Distribution In Coastal Water With Deep Learning Models, Daniel Perez, Kazi Islam, Victoria Hill, Richard Zimmerman, Blake Schaeffer, Yuzhong Shen, Jiang Li Jan 2020

Quantifying Seagrass Distribution In Coastal Water With Deep Learning Models, Daniel Perez, Kazi Islam, Victoria Hill, Richard Zimmerman, Blake Schaeffer, Yuzhong Shen, Jiang Li

OES Faculty Publications

Coastal ecosystems are critically affected by seagrass, both economically and ecologically. However, reliable seagrass distribution information is lacking in nearly all parts of the world because of the excessive costs associated with its assessment. In this paper, we develop two deep learning models for automatic seagrass distribution quantification based on 8-band satellite imagery. Specifically, we implemented a deep capsule network (DCN) and a deep convolutional neural network (CNN) to assess seagrass distribution through regression. The DCN model first determines whether seagrass is presented in the image through classification. Second, if seagrass is presented in the image, it quantifies the seagrass …


Towards Sustained Monitoring Of Subsidence At The Coast Using Insar And Gps: An Application In Hampton Roads, Virginia, Brett Buzzanga, David P.S. Bekaert, Ben D. Hamlington, Simran S. Sangha Jan 2020

Towards Sustained Monitoring Of Subsidence At The Coast Using Insar And Gps: An Application In Hampton Roads, Virginia, Brett Buzzanga, David P.S. Bekaert, Ben D. Hamlington, Simran S. Sangha

OES Faculty Publications

Hampton Roads is among the regions along the U.S. Atlantic Coast experiencing high rates of relative sea level rise. Partly to mitigate subsidence from aquifer compaction, Hampton Roads is injecting treated wastewater into the underlying aquifer. However, the GPS (Global Positioning System) station spacing (∼30 km) is too coarse to capture the spatial variability of subsidence and potential uplift from the injection. We present a cost‐effective workflow for generating an InSAR (interferometric synthetic aperture radar) and GPS combined displacement product. We leverage a live, open‐access archive of InSAR products generated from Sentinel‐1 data. We find an overall subsidence rate of …


Performance Across Worldview-2 And Rapideye For Reproducible Seagrass Mapping, Megan M. Coffer, Blake A. Schaeffer, Richard C. Zimmerman, Victoria Hill, Jiang Li, Kazi A. Islam, Peter J. Whitman Jan 2020

Performance Across Worldview-2 And Rapideye For Reproducible Seagrass Mapping, Megan M. Coffer, Blake A. Schaeffer, Richard C. Zimmerman, Victoria Hill, Jiang Li, Kazi A. Islam, Peter J. Whitman

OES Faculty Publications

Satellite remote sensing offers an effective remedy to challenges in ground-based and aerial mapping that have previously impeded quantitative assessments of global seagrass extent. Commercial satellite platforms offer fine spatial resolution, an important consideration in patchy seagrass ecosystems. Currently, no consistent protocol exists for image processing of commercial data, limiting reproducibility and comparison across space and time. Additionally, the radiometric performance of commercial satellite sensors has not been assessed against the dark and variable targets characteristic of coastal waters. This study compared data products derived from two commercial satellites: DigitalGlobe's WorldView-2 and Planet's RapidEye. A single scene from each platform …


Deep Equatorial Pacific Ocean Oxygenation And Atmospheric Co2 Over The Last Ice Age, Franco Marcantonio, Ryan Hostak, Jennifer E. Hertzberg, Matthew W. Schmidt Jan 2020

Deep Equatorial Pacific Ocean Oxygenation And Atmospheric Co2 Over The Last Ice Age, Franco Marcantonio, Ryan Hostak, Jennifer E. Hertzberg, Matthew W. Schmidt

OES Faculty Publications

Ventilation of carbon stored in the deep ocean is thought to play an important role in atmospheric CO2 increases associated with Pleistocene deglaciations. The presence of this respired carbon has been recorded by an array of paleoceanographic proxies from various locations across the global ocean. Here we present a new sediment core from the Eastern Equatorial Pacific (EEP) Ocean spanning the last 180,000 years and reconstruct high-resolution 230Th-derived fluxes of 232Th and excess barium, along with redox-sensitive uranium concentrations to examine past variations in dust delivery, export productivity, and bottom-water oxygenation, respectively. Our bottom-water oxygenation record is compared to …


Metabolic Profiling Reveals Biochemical Pathways Responsible For Eelgrass Response To Elevated Co2 And Temperature, Carmen C. Zayas-Santiago, Albert Rivas-Ubach, Li-Jung Kuo, Nicholas D. Ward, Richard C. Zimmerman Jan 2020

Metabolic Profiling Reveals Biochemical Pathways Responsible For Eelgrass Response To Elevated Co2 And Temperature, Carmen C. Zayas-Santiago, Albert Rivas-Ubach, Li-Jung Kuo, Nicholas D. Ward, Richard C. Zimmerman

OES Faculty Publications

As CO2 levels in Earth’s atmosphere and oceans steadily rise, varying organismal responses may produce ecological losers and winners. Increased ocean CO2 can enhance seagrass productivity and thermal tolerance, providing some compensation for climate warming. However, the metabolic shifts driving the positive response to elevated CO2 by these important ecosystem engineers remain unknown. We analyzed whole-plant performance and metabolic profiles of two geographically distinct eelgrass (Zostera marina L.) populations in response to CO2 enrichment. In addition to enhancing overall plant size, growth and survival, CO2 enrichment increased the abundance of Calvin Cycle and …


Bacterial Biofilms Colonizing Plastics In Estuarine Waters, With An Emphasis On Vibrio Spp. And Their Antibacterial Resistance, Amanda L. Laverty, Sebastian Primke, Claudia Lorenz, Gunnar Gerdtz, Fred Dobbs Jan 2020

Bacterial Biofilms Colonizing Plastics In Estuarine Waters, With An Emphasis On Vibrio Spp. And Their Antibacterial Resistance, Amanda L. Laverty, Sebastian Primke, Claudia Lorenz, Gunnar Gerdtz, Fred Dobbs

OES Faculty Publications

Since plastics degrade very slowly, they remain in the environment on much longer timescales than most natural organic substrates and provide a novel habitat for colonization by bacterial communities. The spectrum of relationships between plastics and bacteria, however, is little understood. The first objective of this study was to examine plastics as substrates for communities of Bacteria in estuarine surface waters. We used next-generation sequencing of the 16S rRNA gene to characterize communities from plastics collected in the field, and over the course of two colonization experiments, from biofilms that developed on plastic (low-density polyethylene, high-density polyethylene, polypropylene, polycarbonate, polystyrene) …


Modelling Silicate - Nitrate - Ammonium Co-Limitation Of Algal Growth And The Importance Of Bacterial Remineralisation Based On An Experimental Arctic Coastal Spring Bloom Culture Study, Tobias R. Vonnahme, Martial Leroy, Silke Thoms, Dick Van Oevelen, H. Rodger Harvey, Svein Kristiansen, Rolf Gradinger, Christoph Voelker Jan 2020

Modelling Silicate - Nitrate - Ammonium Co-Limitation Of Algal Growth And The Importance Of Bacterial Remineralisation Based On An Experimental Arctic Coastal Spring Bloom Culture Study, Tobias R. Vonnahme, Martial Leroy, Silke Thoms, Dick Van Oevelen, H. Rodger Harvey, Svein Kristiansen, Rolf Gradinger, Christoph Voelker

OES Faculty Publications

Arctic coastal ecosystems are rapidly changing due to climate warming, which makes modelling their productivity crucially important to better understand future changes. System primary production in these systems is highest during the pronounced spring bloom, typically dominated by diatoms. Eventually the spring blooms terminate due to silicon or nitrogen limitation. Bacteria can play an important role for extending bloom duration and total CO2 fixation through ammonium regeneration. Current ecosystem models often simplify the effects of nutrient co-limitations on algal physiology and cellular ratios and neglect bacterial driven regeneration, leading to an underestimation of primary production. Detailed biochemistry- and cell-based models …


Corrigendum To "Upper Water Structure And Mixed Layer Depth In Tropical Waters: The Seats Station In The Northern South China Sea, Jen-Hua Tai, George T.F. Wong, Xiaoju Pan Jan 2020

Corrigendum To "Upper Water Structure And Mixed Layer Depth In Tropical Waters: The Seats Station In The Northern South China Sea, Jen-Hua Tai, George T.F. Wong, Xiaoju Pan

OES Faculty Publications

No abstract provided.


The Impact Of Eddies On Nutrient Supply, Diatom Biomass And Carbon Export In The Northern South China Sea, Yung-Yen Shih, Chin-Chang Hung, Sing-How Tuo, Huan-Jie Shao, Chun Hoe Chow, Francois L.L. Muller, Yuan-Hong Cai Jan 2020

The Impact Of Eddies On Nutrient Supply, Diatom Biomass And Carbon Export In The Northern South China Sea, Yung-Yen Shih, Chin-Chang Hung, Sing-How Tuo, Huan-Jie Shao, Chun Hoe Chow, Francois L.L. Muller, Yuan-Hong Cai

OES Faculty Publications

We have investigated the effect of eddies (cold and warm eddies, CEs and WEs) on the nutrient supply to the euphotic zone and the organic carbon export from the euphotic zone to deeper parts of the water column in the northern South China Sea. Besides basic hydrographic and biogeochemical parameters, the flux of particulate organic carbon (POC), a critical index of the strength of the oceanic biological pump, was also measured at several locations within two CEs and one WE using floating sediment traps deployed below the euphotic zone. The POC flux associated with the CEs (85 ± 55 mg-C …