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Full-Text Articles in Physical Sciences and Mathematics

Comparison Of Electrochemical Polishing Treatments Between Phosphoric Acid And A Deep Eutectic Solvent For High-Purity Copper, Tarek M. Abdel-Fattah, Jon Derek Loftis Jan 2022

Comparison Of Electrochemical Polishing Treatments Between Phosphoric Acid And A Deep Eutectic Solvent For High-Purity Copper, Tarek M. Abdel-Fattah, Jon Derek Loftis

VIMS Articles

This study investigated and compared the acid-free electropolishing of copper with the state-of-the-art acidic electropolishing process. The acid-free medium used in this study is based on a deep eutectic solvent comprised of 2:1 ethylene glycol and choline chloride. The electrochemical study included voltammetry and chronoamperometry tests during the electropolishing process. The characterization techniques used were atomic force microscopy (AFM) and digital microscopy, and surface morphology comparisons summarized the electropolishing efficiency of phosphoric acid and acid-free deep eutectic solvent treatments for high-purity copper. Electropolishing copper with a deep eutectic solvent resulted in a mirror finish and a post-treatment surface that was …


The Spatio-Temporal Distribution And Transport Of Suspended Sediment In Laizhou Bay: Insights From Hydrological And Sedimentological Investigations, Bo Xie, Rui Bao, Dongxiao Yin, Et Al Jan 2022

The Spatio-Temporal Distribution And Transport Of Suspended Sediment In Laizhou Bay: Insights From Hydrological And Sedimentological Investigations, Bo Xie, Rui Bao, Dongxiao Yin, Et Al

VIMS Articles

Suspended sediment transport and deposition are crucial physical processes controlling the geomorphological evolution of estuaries and bays. Specially, under the context of worldwide coastal erosion, knowledge of the spatio-temporal distribution of suspended sediment concentration (SSC) and its associated sediment load have become increasingly important for bay management. However, our understanding of the mechanisms of suspended sediment dynamics continues to be hampered by the lack of high-resolution observations. Here, we present a study of the transport mechanisms and controlling factors of suspended sediment over Laizhou Bay. For this, we conducted continuous measurements of SSC, salinity, temperature, and flow velocity at nine …


Seasonal Controls On Nearshore Dissolved Oxygen Variability And Hypoxia In A Coastal Embayment, Ryan K. Walter, Stephen A. Huie, (...), Piero L.F. Mazzini, Ian Robbins Jan 2022

Seasonal Controls On Nearshore Dissolved Oxygen Variability And Hypoxia In A Coastal Embayment, Ryan K. Walter, Stephen A. Huie, (...), Piero L.F. Mazzini, Ian Robbins

VIMS Articles

Declining dissolved oxygen (DO) is emerging as an increasingly important stressor in nearshore ecosystems, and there is a growing need to better understand DO dynamics and hypoxia risk in this highly variable environment. In this study, we collected data from monthly cruises on the inner shelf, continuous nearshore moorings inside and outside a small coastal upwelling embayment (San Luis Obispo Bay in Central California), and weekly phytoplankton measurements inside the bay during the upwelling season. Nearshore DO was generally dominated by low-frequency synoptic variability, with increased DO variance near the surface relative to the bottom and inside the bay compared …


A Numerical Investigation Of Hurricane Florence-Induced Compound Flooding In The Cape Fear Estuary Using A Dynamically Coupled Hydrological-Ocean Model, Daoyang Bao, Z. George Xue, John C. Warner, Melissa Moulton, Dongxiao Yin, Et Al Jan 2022

A Numerical Investigation Of Hurricane Florence-Induced Compound Flooding In The Cape Fear Estuary Using A Dynamically Coupled Hydrological-Ocean Model, Daoyang Bao, Z. George Xue, John C. Warner, Melissa Moulton, Dongxiao Yin, Et Al

VIMS Articles

Hurricane-induced compound flooding is a combined result of multiple processes, including overland runoff, precipitation, and storm surge. This study presents a dynamical coupling method applied at the boundary of a processes-based hydrological model (the hydrological modeling extension package of the Weather Research and Forecasting model) and the two-dimensional Regional Ocean Modeling System on the platform of the Coupled-Ocean-Atmosphere-Wave-Sediment Transport Modeling System. The coupled model was adapted to the Cape Fear River Basin and adjacent coastal ocean in North Carolina, United States, which suffered severe losses due to the compound flood induced by Hurricane Florence in 2018. The model's robustness was …


Drivers And Seasonal Variability Of Redox-Sensitive Metal Chemistry In A Shallow Subterranean Estuary, Alison E. O'Connor, Elizabeth A. Canuel, Aaron J. Beck Jan 2022

Drivers And Seasonal Variability Of Redox-Sensitive Metal Chemistry In A Shallow Subterranean Estuary, Alison E. O'Connor, Elizabeth A. Canuel, Aaron J. Beck

VIMS Articles

The subterranean estuary (STE) has been historically defined in terms of the mixing of saline and fresh water, in an analogy to surface estuaries. However, redox gradients are also a defining characteristic of the STE and influence its role as a source or sink for metals in the environment. Approaching the STE from a redox-focused biogeochemical perspective (e.g., considering the role of microbial respiration and availability of organic matter) provides the ability to quantify drivers of metal transport across spatial and temporal scales. This study measured the groundwater composition of a shallow STE over 2 years and used multiple linear …


Dynamical Controls Of The Eastward Transport Of Overwintering Calanus Finmarchicus From The Lofoten Basin To The Continental Slope, Huizi Dong, Meng Zhou, Walker O. Smith Jr., Et Al Jan 2022

Dynamical Controls Of The Eastward Transport Of Overwintering Calanus Finmarchicus From The Lofoten Basin To The Continental Slope, Huizi Dong, Meng Zhou, Walker O. Smith Jr., Et Al

VIMS Articles

Diapausing populations of Calanus finmarchicus at depth in the Lofoten Basin (LB) return to the continental shelf and slope off the Lofoten-Vesterålen Islands during the phytoplankton spring bloom to feed and spawn, forming surface swarms with a great abundance. To study how overwintering populations of C. finmarchicus move with the deep currents and return to the shelf, Lagrangian transport characteristics of particles in deep water between 2008 and 2019 were analyzed using Global Ocean Reanalysis and Simulation re-analysis data and Lagrangian Coherent Structures (LCSs). Our analyses revealed that persistent eastward transport of diapausing C. finmarchicus between LB and continental slope …


Vertical Transport Timescale Of Surface-Produced Particulate Material In The Chesapeake Bay, Jilian Xiong, Jian Shen Jan 2022

Vertical Transport Timescale Of Surface-Produced Particulate Material In The Chesapeake Bay, Jilian Xiong, Jian Shen

VIMS Articles

Accumulation and remineralization of surface-produced particulate organic matter (POM) in the water column and seabed link closely to hypoxia and the health of aquatic ecosystems. The POM retention time provides a key timescale to interpret biochemical reaction processes. In this study, we investigated the spatiotemporal variations in the vertical particulate age (VPA) of surface-produced POM, which is the mean time elapsed since the particulates last contact the surface, by incorporating major physical processes including sinking, resuspension, and deposition in the Chesapeake Bay. It was found that the vertical transport time for the particulates (i.e., VPA) is much longer than the …


Leveraging The Interdependencies Between Barrier Islands And Backbarrier Saltmarshes To Enhance Resilience To Sea-Level Rise, Christopher J. Hein, Michael S. Fenster, Keryn B. Gedan, Jeff R. Tabar, Emily A. Hein, Todd Demunda Sep 2021

Leveraging The Interdependencies Between Barrier Islands And Backbarrier Saltmarshes To Enhance Resilience To Sea-Level Rise, Christopher J. Hein, Michael S. Fenster, Keryn B. Gedan, Jeff R. Tabar, Emily A. Hein, Todd Demunda

VIMS Articles

Barrier islands and their backbarrier saltmarshes have a reciprocal relationship: aeolian and storm processes transport sediment from the beaches and dunes to create and build marshes along the landward fringe of the island. In turn, these marshes exert a stabilizing influence on the barrier by widening the barrier system and forming a platform onto which the island migrates, consequently slowing landward barrier migration and inhibiting storm breaching. Here, we present a novel framework for applying these natural interdependencies to managing coastal systems and enhancing barrier-island resilience. Further, we detail application of these principles through a case study of the design …


Membrane Inlet Mass Spectrometry Method (Reox/Mims) To Measure 15n-Nitrate In Isotope-Enrichment Experiments, Xianbiao Lin, Kaijun Lu, Amber K. Hardison, Et Al Jul 2021

Membrane Inlet Mass Spectrometry Method (Reox/Mims) To Measure 15n-Nitrate In Isotope-Enrichment Experiments, Xianbiao Lin, Kaijun Lu, Amber K. Hardison, Et Al

VIMS Articles

Using 15N stable isotope as a tracer to quantify N transformation rates in isotope-enrichment experiments improves understanding of the N cycle in various ecosystems. However, measuring 15N-nitrate (15NO3) in small volumes of water for these experiments is a major challenge due to the inconvenience of preparing samples by traditional techniques. We developed a “REOX/MIMS” method by applying membrane inlet mass spectrometry (MIMS) to determining 15NO3 concentrations in a small volumes of water from isotope-enrichment experiments after converting the dissolved inorganic N to N2. The nitrates (NO3− …


Nonlinearity Of Subtidal Estuarine Circulation In The Pearl River Estuary, China, Hongzhou Xu, Jian Shen, Dongxiao Wang, Lin Luo, Bo Hong Jun 2021

Nonlinearity Of Subtidal Estuarine Circulation In The Pearl River Estuary, China, Hongzhou Xu, Jian Shen, Dongxiao Wang, Lin Luo, Bo Hong

VIMS Articles

The Pearl River Estuary (PRE) is a bell-shaped estuary with a narrow deep channel and wide shoals. This unique topographic feature leads to different dynamics of the subtidal estuarine circulation (SEC) in the PRE compared with a narrow and straight estuary. In this study, the nonlinear dynamics of the SEC in the PRE under mean circumstance are analyzed by using a validated 3D numerical model. Model results show that the nonlinear advections reach leading order in the along-channel momentum balance. Modulated by tide, the nonlinear advections show significant temporal variations as they have much larger values during spring tide than …


Formation Of Oil-Particle-Aggregates: Numerical Model Formulation And Calibration, Linlin Cui, Courtney K. Harris, Danielle R.N. Tarpley May 2021

Formation Of Oil-Particle-Aggregates: Numerical Model Formulation And Calibration, Linlin Cui, Courtney K. Harris, Danielle R.N. Tarpley

VIMS Articles

When oil spills occur in turbid waters, the oil droplets and mineral grains can combine to form oil-particle aggregates (OPAs). The formation of OPAs impacts the vertical transport of both the oil and the mineral grains; especially increasing deposition of oil to the seabed. Though the coastal oceans can be very turbid, to date, few numerical ocean models have accounted for aggregation processes that form OPAs. However, interactions between oil and mineral aggregates may be represented using techniques developed to account for sediment aggregation. As part of Consortium for Simulation of Oil Microbial Interactions in the Ocean (CSOMIO), we modified …


Vegetation Type And Decomposition Priming Mediate Brackish Marsh Carbon Accumulation Under Interacting Facets Of Global Change, Anthony J. Rietl, J. Patrick Megonigal, Ellen R. Herbert, Matthew L. Kirwan Apr 2021

Vegetation Type And Decomposition Priming Mediate Brackish Marsh Carbon Accumulation Under Interacting Facets Of Global Change, Anthony J. Rietl, J. Patrick Megonigal, Ellen R. Herbert, Matthew L. Kirwan

VIMS Articles

Coastal wetland carbon pools are globally important, but their response to interacting facets of global change remain unclear. Numerical models neglect species-specific vegetation responses to sea level rise (SLR) and elevated CO2 (eCO2) that are observed in field experiments, while field experiments cannot address the long-term feedbacks between flooding and soil growth that models show are important. Here, we present a novel numerical model of marsh carbon accumulation parameterized with empirical observations from a long-running eCO2 experiment in an organic rich, brackish marsh. Model results indicate that eCO2 and SLR interact …


The Geomorphic Impact Of Mangrove Encroachment In An Australian Salt Marsh, Daniel J. Coleman, Kerrylee Rogers, D. Reide Corbett, Christopher J. Owers, Matthew L. Kirwan Apr 2021

The Geomorphic Impact Of Mangrove Encroachment In An Australian Salt Marsh, Daniel J. Coleman, Kerrylee Rogers, D. Reide Corbett, Christopher J. Owers, Matthew L. Kirwan

VIMS Articles

Mangroves are encroaching into salt marshes throughout the world as a result of environmental change. Previous studies suggest mangroves trap sediment more efficiently than adjacent salt marshes, providing mangroves greater capacity to adapt to sea level rise; this may occur by displacing salt marshes. However, sediment transport in adjacent marsh-mangrove systems and its role in mangrove encroachment upon salt marsh remain poorly understood. Here we directly test the hypothesis that mangroves reduce the ability of adjacent marsh to adjust to sea level rise by measuring sediment transport across salt marsh platforms, with and without 6 m of fringing mangroves at …


Quantifying Thresholds Of Barrier Geomorphic Change In A Cross-Shore Sediment-Partitioning Model, Daniel J. Ciarletta, Jennifer L. Miselis, Justin L. Shawler, Christopher J. Hein Mar 2021

Quantifying Thresholds Of Barrier Geomorphic Change In A Cross-Shore Sediment-Partitioning Model, Daniel J. Ciarletta, Jennifer L. Miselis, Justin L. Shawler, Christopher J. Hein

VIMS Articles

Barrier coasts, including barrier islands, beach-ridge plains, and associated landforms, can assume a broad spectrum of morphologies over multi-decadal scales that reflect conditions of sediment availability, accommodation, and relative sea-level rise. However, the quantitative thresholds of these controls on barrier-system behavior remain largely unexplored, even as modern sea-level rise and anthropogenic modification of sediment availability increasingly reshape the world's sandy coastlines. In this study, we conceptualize barrier coasts as sediment-partitioning frameworks, distributing sand delivered from the shoreface to the subaqueous and subaerial components of the coastal system. Using an idealized morphodynamic model, we explore thresholds of behavioral and morphologic change …


Development Of The Csomio Coupled Ocean-Oil-Sediment- Biology Model, Dmitry S. Dukhovskoy, Steven L. . Morey, (...), Courtney K. Harris, Et Al Mar 2021

Development Of The Csomio Coupled Ocean-Oil-Sediment- Biology Model, Dmitry S. Dukhovskoy, Steven L. . Morey, (...), Courtney K. Harris, Et Al

VIMS Articles

The fate and dispersal of oil in the ocean is dependent upon ocean dynamics, as well as transformations resulting from the interaction with the microbial community and suspended particles. These interaction processes are parameterized in many models limiting their ability to accurately simulate the fate and dispersal of oil for subsurface oil spill events. This paper presents a coupled ocean-oil-biology-sediment modeling system developed by the Consortium for Simulation of Oil-Microbial Interactions in the Ocean (CSOMIO) project. A key objective of the CSOMIO project was to develop and evaluate a modeling framework for simulating oil in the marine environment, including its …


Different Coastal Marsh Sites Reflect Similar Topographic Conditions Under Which Bare Patches And Vegetation Recovery Occur, Chen Wang, Lennert Schepers, Matthew L. Kirwan, Et Al Feb 2021

Different Coastal Marsh Sites Reflect Similar Topographic Conditions Under Which Bare Patches And Vegetation Recovery Occur, Chen Wang, Lennert Schepers, Matthew L. Kirwan, Et Al

VIMS Articles

The presence of bare patches within otherwise vegetated coastal marshes is sometimes considered to be a symptom of marsh dieback and the subsequent loss of important ecosystem services. Here we studied the topographical conditions determining the presence and revegetation of bare patches in three marsh sites with contrasting tidal range, sediment supply, and plant species: the Scheldt estuary (the Netherlands), Venice lagoon (Italy), and Blackwater marshes (Maryland, USA). Based on GIS (geographic information system) analyses of aerial photos and lidar imagery of high resolution (≤2×2 m pixels), we analyzed the topographic conditions under which bare patches occur, including their surface …


A Regional, Early Spring Bloom Of Phaeocystis Pouchetii On The New England Continental Shelf, Walker O. Smith Jr., Weifeng G. Zhang, Andrew Hirzel, Et Al Feb 2021

A Regional, Early Spring Bloom Of Phaeocystis Pouchetii On The New England Continental Shelf, Walker O. Smith Jr., Weifeng G. Zhang, Andrew Hirzel, Et Al

VIMS Articles

The genus Phaeocystis is distributed globally and has considerable ecological, biogeochemical, and societal impacts. Understanding its distribution, growth and ecological impacts has been limited by lack of extensive observations on appropriate scales. In 2018, we investigated the biological dynamics of the New England continental shelf and encountered a substantial bloom of Phaeocystis pouchetii. Based on satellite imagery during January through April, the bloom extended over broad expanses of the shelf; furthermore, our observations demonstrated that it reached high biomass levels, with maximum chlorophyll concentrations exceeding 16 μg L−1 and particulate organic carbon levels > 95 μmol L−1. Initially, the bloom was …


Coastal Forest Seawater Exposure Increases Stem Methane Concentration, Matthew J. Norwood, Nicholas Ward, (......), Matthew L. Kirwan, Anya Hopple, J. Patrick Megonigal Feb 2021

Coastal Forest Seawater Exposure Increases Stem Methane Concentration, Matthew J. Norwood, Nicholas Ward, (......), Matthew L. Kirwan, Anya Hopple, J. Patrick Megonigal

VIMS Articles

Methane (CH4) exchange between trees and the atmosphere has recently emerged as an important, but poorly quantified process regulating global climate. The sources (soil and/or tree) and mechanisms driving the increase of CH4 in trees and degassing to the atmosphere are inadequately understood, particularly for coastal forests facing increased exposure to seawater. We investigated the eco‐physiological relationship between tree stem wood density, soil and stem oxygen saturation (an indicator of redox state), soil and stem CH4 concentrations, soil and stem carbon dioxide (CO2) concentrations, and soil salinity in five forests along the United States …


Effects Of Reduced Shoreline Erosion On Chesapeake Bay Water Clarity, Jessica S. Turner, Pierre St-Laurent, Marjorie A.M. Friedrichs, Carl T. Friedrichs Jan 2021

Effects Of Reduced Shoreline Erosion On Chesapeake Bay Water Clarity, Jessica S. Turner, Pierre St-Laurent, Marjorie A.M. Friedrichs, Carl T. Friedrichs

VIMS Articles

Shoreline erosion supplies sediments to estuaries and coastal waters, influencing water clarity and primary production. Globally, shoreline erosion sediment inputs are changing with anthropogenic alteration of coastlines in populated regions. Chesapeake Bay, a prime example of such a system where shoreline erosion accounts for a large proportion of sediments entering the estuary, serves here as a case study for investigating the effects of changing sediment inputs on water clarity. Long-term increases in shoreline armoring have contributed to decreased erosional sediment inputs to the estuary, changing the composition of suspended particles in surface waters. This study examined the impact of shoreline …


The Effect Of Coastal Landform Development On Decadal-To Millennial-Scale Longshore Sediment Fluxes: Evidence From The Holocene Evolution Of The Central Mid-Atlantic Coast, Usa, Justin L. Shawler, Christopher J. Hein, Chloe A. Obara, Mahina G. Robbins, Sebastien Huot, Michael S. Fenster Jan 2021

The Effect Of Coastal Landform Development On Decadal-To Millennial-Scale Longshore Sediment Fluxes: Evidence From The Holocene Evolution Of The Central Mid-Atlantic Coast, Usa, Justin L. Shawler, Christopher J. Hein, Chloe A. Obara, Mahina G. Robbins, Sebastien Huot, Michael S. Fenster

VIMS Articles

The behavior of siliciclastic coastal systems is largely controlled by the interplay between accommodation creation and infilling. Factors responsible for altering sediment fluxes to and along open-ocean coasts include cross-shore mobilization of sediment primarily from tidal currents and storms as well as changes in alongshore transport rates moderated by changing wave conditions, river sediment inputs, artificial shoreline hardening and modification, and natural sediment trapping in updrift coastal landforms. This paper focuses on the latter relationships. To address understudied interactions between updrift coastal landforms and downdrift coastal behavior, we quantify the volume and fluxes of sediment trapped in the Assateague-Chincoteague-Wallops barrier-island …


Molluscan Aminostratigraphy Of The Us Mid-Atlantic Quaternary Coastal System: Implications For Onshore-Offshore Correlation, Paleochannel And Barrier Island Evolution, And Local Late Quaternary Sea-Level History, John F. Wehmiller, Laura L. Brothers, (...), Christopher J. Hein, Justin L. Shawler Jan 2021

Molluscan Aminostratigraphy Of The Us Mid-Atlantic Quaternary Coastal System: Implications For Onshore-Offshore Correlation, Paleochannel And Barrier Island Evolution, And Local Late Quaternary Sea-Level History, John F. Wehmiller, Laura L. Brothers, (...), Christopher J. Hein, Justin L. Shawler

VIMS Articles

The Quaternary record of the US Mid-Atlantic coastal system includes onshore emergent late Pleistocene shoreline deposits, offshore inner shelf and barrier island units, and paleovalleys formed during multiple glacial stage sea-level lowstands. The geochronology of this coastal system is based on uranium series, radiocarbon, amino acid racemization (AAR), and optically stimulated luminescence (OSL) methods. We report over 600 mollusk AAR results from 93 sites between northeastern North Carolina and the central New Jersey shelf, representing samples from both onshore cores or outcrops, sub-barrier and offshore cores, and transported shells from barrier island beaches. AAR age estimates are constrained by paired …


Mechanisms Of Pond Expansion In A Rapidly Submerging Marsh, Joshua Himmelstein, Orencio Duran Vinent, Stijn Temmerman, Matthew L. Kirwan Jan 2021

Mechanisms Of Pond Expansion In A Rapidly Submerging Marsh, Joshua Himmelstein, Orencio Duran Vinent, Stijn Temmerman, Matthew L. Kirwan

VIMS Articles

The development and expansion of ponds within otherwise vegetated coastal marshes is a primary driver of marsh loss throughout the world. Previous studies propose that large ponds expand through a wind wave-driven positive feedback, where pond edge erosion rates increase with pond size, whereas biochemical processes control the formation and expansion of smaller ponds. However, it remains unclear which mechanisms dominate at a given scale, and thus how, and how fast, ponds increase their size. Here, we use historical photographs and field measurements in a rapidly submerging microtidal marsh to quantify pond development and identify the processes involved. We find …


Revisiting The Ocean Color Algorithms For Particulate Organic Carbon And Chlorophyll-A Concentrations In The Ross Sea, Shuangling Chen, Walker O. Smith Jr., Xiaolei Yu Jan 2021

Revisiting The Ocean Color Algorithms For Particulate Organic Carbon And Chlorophyll-A Concentrations In The Ross Sea, Shuangling Chen, Walker O. Smith Jr., Xiaolei Yu

VIMS Articles

The Ross Sea is the most productive marginal sea in the Southern Ocean and plays an important role in carbon cycling. However, limited sampling of Chlorophyll-a (Chl) and particulate organic carbon (POC) concentrations from research expeditions constrains our understanding of the biogeochemical processes there. Satellites provide a useful tool for synoptic mapping of surface water properties on regional and global scales, yet the general applicability of the published algorithms in the Ross Sea is poorly known. Based on the data collected from 18 cruises in the past 20 years, we analyzed both the NASA standard and locally developed Chl and …


Biophysical Controls Of Marsh Soil Shear Strength Along An Estuarine Salinity Gradient, Megan N. Gillen, Tyler C. Messerschmidt, Matthew L. Kirwan Jan 2021

Biophysical Controls Of Marsh Soil Shear Strength Along An Estuarine Salinity Gradient, Megan N. Gillen, Tyler C. Messerschmidt, Matthew L. Kirwan

VIMS Articles

Sea-level rise, saltwater intrusion, and wave erosion threaten coastal marshes, but the influence of salinity on marsh erodibility remains poorly understood. We measured the shear strength of marsh soils along a salinity and biodiversity gradient in the York River estuary in Virginia to assess the direct and indirect im-pacts of salinity on potential marsh erodibility. We found that soil shear strength was higher in monospecific salt marshes (5–36 kPa) than in biodiverse freshwater marshes (4–8 kPa), likely driven by differences in below ground biomass. However, we also found that shear strength at the marsh edge was controlled by sediment characteristics, …


On The Human Appropriation Of Wetland Primary Production, James E. Cloern, Samuel M. Safran, Lydia Smith Vaughn, (...), Elizabeth A. Canuel, J.Letitia Grenier Jan 2021

On The Human Appropriation Of Wetland Primary Production, James E. Cloern, Samuel M. Safran, Lydia Smith Vaughn, (...), Elizabeth A. Canuel, J.Letitia Grenier

VIMS Articles

Humans are changing the Earth's surface at an accelerating pace, with significant consequences for ecosystems and their biodiversity. Landscape transformation has far-reaching implications including reduced net primary production (NPP) available to support ecosystems, reduced energy supplies to consumers, and disruption of ecosystem services such as carbon storage. Anthropogenic activities have reduced global NPP available to terrestrial ecosystems by nearly 25%, but the loss of NPP from wetland ecosystems is unknown. We used a simple approach to estimate aquatic NPP from measured habitat areas and habitat-specific areal productivity in the largest wetland complex on the USA west coast, comparing historical and …


Diatom Hotspots Driven By Western Boundary Current Instability, Hilde Oliver, Weifeng G. Zhang, Walker O. Smith Jr., Et Al Jan 2021

Diatom Hotspots Driven By Western Boundary Current Instability, Hilde Oliver, Weifeng G. Zhang, Walker O. Smith Jr., Et Al

VIMS Articles

Climatic changes have decreased the stability of the Gulf Stream (GS), increasing the frequency at which its meanders interact with the Mid-Atlantic Bight (MAB) continental shelf and slope region. These intrusions are thought to suppress biological productivity by transporting low-nutrient water to the otherwise productive shelf edge region. Here we present evidence of widespread, anomalously intense subsurface diatom hotspots in the MAB slope sea that likely resulted from a GS intrusion in July 2019. The hotspots (at ∼50 m) were associated with water mass properties characteristic of GS water (∼100 m); it is probable that the hotspots resulted from the …


Onset Of Runaway Fragmentation Of Salt Marshes, Orencio Duran Vinent, Ellen R. Herbert, Daniel J. Coleman, Joshua D. Himmelstein, Matthew L. Kirwan Jan 2021

Onset Of Runaway Fragmentation Of Salt Marshes, Orencio Duran Vinent, Ellen R. Herbert, Daniel J. Coleman, Joshua D. Himmelstein, Matthew L. Kirwan

VIMS Articles

Salt marshes are valuable but vulnerable coastal ecosystems that adapt to relative sea level rise (RSLR) by accumulating organic matter and inorganic sediment. The natural limit of these processes defines a threshold rate of RSLR beyond which marshes drown, resulting in ponding and conversion to open waters. We develop a simplified formulation for sediment transport across marshes to show that pond formation leads to runaway marsh fragmentation, a process characterized by a self-similar hierarchy of pond sizes with power-law distributions. We find the threshold for marsh fragmentation scales primarily with tidal range and that sediment supply is only relevant where …


Long-Term Trends In Chesapeake Bay Remote Sensing Reflectance: Implications For Water Clarity, Jessica S. Turner, Carl T. Friedrichs, Marjorie A.M. Friedrichs Jan 2021

Long-Term Trends In Chesapeake Bay Remote Sensing Reflectance: Implications For Water Clarity, Jessica S. Turner, Carl T. Friedrichs, Marjorie A.M. Friedrichs

VIMS Articles

While ecosystem health is improving in many estuaries worldwide following nutrient reductions, inconsistent trends in water clarity often remain. The Chesapeake Bay, a eutrophic estuary with a highly populated watershed, is a crucial testbed for these concerns. Improved efforts are needed to understand why some measurements of downstream estuarine water clarity appear to be uncorrelated with watershed management actions, and multiple metrics of clarity are needed to address this issue. To complement in situ measurements, satellite remote sensing provides an additional tool with which to assess long-term change in water clarity. In this study, remote sensing reflectance (Rrs) from the …


Experimental Tree Mortality Does Not Induce Marsh Transgression In A Chesapeake Bay Low-Lying Coastal Forest, David C. Walters, Joel A. Carr, (...), Matthew L. Kirwan, Et Al Jan 2021

Experimental Tree Mortality Does Not Induce Marsh Transgression In A Chesapeake Bay Low-Lying Coastal Forest, David C. Walters, Joel A. Carr, (...), Matthew L. Kirwan, Et Al

VIMS Articles

Transgression into adjacent uplands is an important global response of coastal wetlands to accelerated rates of sea level rise. “Ghost forests” mark a signature characteristic of marsh transgression on the landscape, as changes in tidal inundation and salinity cause bordering upland tree mortality, increase light availability, and the emergence of tidal marsh species due to reduced competition. To investigate these mechanisms of the marsh migration process, we conducted a field experiment to simulate a natural disturbance event (e.g., storm-induced flooding) by inducing the death of established trees (coastal loblolly pine, Pinus taeda) at the marsh-upland forest ecotone. After this simulated …


Sea Ice Suppression Of Co2 Outgassing In The West Antarctic Peninsula: Implications For The Evolving Southern Ocean Carbon Sink, E.H. Shadwick, O.A. De Meo, S. Schroeter, M.C. Arroyo, D.G. Martinson, H. Ducklow Jan 2021

Sea Ice Suppression Of Co2 Outgassing In The West Antarctic Peninsula: Implications For The Evolving Southern Ocean Carbon Sink, E.H. Shadwick, O.A. De Meo, S. Schroeter, M.C. Arroyo, D.G. Martinson, H. Ducklow

VIMS Articles

The Southern Ocean plays an important role in the uptake of atmospheric CO2. In seasonally ice-covered regions, estimates of air-sea exchange remain uncertain in part because of a lack of observations outside the summer season. Here we present new estimates of air-sea CO2 flux in the West Antarctic Peninsula (WAP) from an autonomous mooring on the continental shelf. In summer, the WAP is a sink for atmospheric CO2 followed by a slow return to atmospheric equilibrium in autumn and winter. Outgassing is almost entirely suppressed by ice cover from June through October, resulting in a modest …