Physical Sciences and Mathematics Commons^™

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 …

A Cross-Scale Study For Compound Flooding Processes During Hurricane Florence, Fei Ye, Wei Huang, Yinglong J. Zhang, Et Al

VIMS Articles

We study the compound flooding processes that occurred in Hurricane Florence (2018), which was accompanied by heavy precipitation, using a 3D creek-to-ocean hydrodynamic model. We examine the important role played by barrier islands in the observed compound surges in the coastal watershed. Locally very high resolution is used in some watershed areas in order to resolve small features that turn out to be critical for capturing the observed high watermarks locally. The wave effects are found to be significant near barrier islands and have contributed to some observed over-toppings and breaches. Results from sensitivity tests applying each of the three …

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

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 …

Connectivity: Insights From The U.S. Long Term Ecological Research Network, David M. Iwaniec, Michael Gooseff, Katherine N. Suding, David S. Johnson, Et Al

VIMS Articles

Ecosystems across the United States are changing in complex and surprising ways. Ongoing demand for critical ecosystem services requires an understanding of the populations and communities in these ecosystems in the future. This paper represents a synthesis effort of the U.S. National Science Foundation-funded Long-Term Ecological Research (LTER) network addressing the core research area of “populations and communities.” The objective of this effort was to show the importance of long-term data collection and experiments for addressing the hardest questions in scientific ecology that have significant implications for environmental policy and management. Each LTER site developed at least one compelling case …

Estuaries As Filters For Riverine Microplastics: Simulations In A Large, Coastal-Plain Estuary, Alexander G. Lopez, Raymond G. Najjar, Marjorie A.M. Friedrichs, Michael A. Hickner, Denice H. Wardrop

VIMS Articles

Public awareness of microplastics and their widespread presence throughout most bodies of water are increasingly documented. The accumulation of microplastics in the ocean, however, appears to be far less than their riverine inputs, suggesting that there is a “missing sink” of plastics in the ocean. Estuaries have long been recognized as filters for riverine material in marine biogeochemical budgets. Here we use a model of estuarine microplastic transport to test the hypothesis that the Chesapeake Bay, a large coastal-plain estuary in eastern North America, is a potentially large filter, or “sink,” of riverine microplastics. The 1-year composite simulation, which tracks …

Anticipating And Adapting To The Future Impacts Of Climate Change On The Health, Security And Welfare Of Low Elevation Coastal Zone (Lecz) Communities In Southeastern Usa, T. Allen, J. Behr, (...), Jon Derek Loftis, Molly Mitchell, Karinna Nunez, Et Al

VIMS Articles

Low elevation coastal zones (LECZ) are extensive throughout the southeastern United States. LECZ communities are threatened by inundation from sea level rise, storm surge, wetland degradation, land subsidence, and hydrological flooding. Communication among scientists, stake-holders, policy makers and minority and poor residents must improve. We must predict processes spanning the ecological, physical, social, and health sciences. Communities need to address linkages of (1) human and socioeconomic vulnerabilities; (2) public health and safety; (3) economic concerns; (4) land loss; (5) wetland threats; and (6) coastal inundation. Essential capabilities must include a network to assemble and distribute data and model code to …

Preparing Scientists, Policy-Makers, And Managers For A Fast-Forward Future, Richard B. Norgaard, John A. Wiens, (...), Elizabeth A. Canuel, Et Al

VIMS Articles

Ecosystems in the Sacramento–San Joaquin Delta are changing rapidly, as are ecosystems around the world. Extreme events are becoming more frequent and thresholds are likely to be crossed more often, creating greater uncertainty about future conditions. The accelerating speed of change means that ecological systems may not remain stable long enough for scientists to understand them, much less use their research findings to inform policy and management. Faced with these challenges, those involved in science, policy, and management must adapt and change and anticipate what the ecosystems may be like in the future. We highlight several ways of looking ahead—scenario …

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 …

Real-Time Environmental Forecasts Of The Chesapeake Bay: Model Setup, Improvements, And Online Visualization, Aaron Bever, Marjorie A.M. Friedrichs, Pierre St-Laurent

VIMS Articles

Daily real-time nowcasts (current conditions) and 2-day forecasts of environmental conditions in the Chesapeake Bay have been continuously available for 4 years. The forecasts use a 3-D hydrodynamic-biogeochemical model with 1–2 km resolution and 3-D output every 6 h that includes salinity, water temperature, pH, aragonite saturation state, alkalinity, dissolved oxygen, and hypoxic volume. Visualizations of the forecasts are available through a local institutional website (www.vims.edu/hypoxia) and the MARACOOS Oceans Map portal (https://oceansmap.maracoos.org/chesapeake-bay/). Modifications to real-time graphics on the local website are routinely made based on stakeholder input and are formatted for use on a mobile …

Mechanisms Driving Decadal Changes In The Carbonate System Of A Coastal Plain Estuary, Fei Da, Marjorie A.M. Friedrichs, Pierre St-Laurent, Elizabeth Shadwick, Raymond G. Najjaar, Kyle E. Hinson

VIMS Articles

Understanding decadal changes in the coastal carbonate system is essential for predicting how the health of these waters responds to anthropogenic drivers, such as changing atmospheric conditions and riverine inputs. However, studies that quantify the relative impacts of these drivers are lacking. In this study, the primary drivers of decadal trends in the surface carbonate system, and the spatiotemporal variability in these trends, are identified for a large coastal plain estuary: the Chesapeake Bay. Experiments using a coupled three-dimensional hydrodynamic-biogeochemical model highlight that, over the past three decades, the changes in the surface carbonate system of Chesapeake Bay have strong …

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 …

A Data Repository For Extent And Causes Of Chesapeake Bay Warming, Kyle E. Hinson, Marjorie A.M. Friedrichs, Pierre St-Laurent

Data

This data repository is a permanent archive of the results presented in the associated publication (Hinson et al. 2021, Journal of the American Water Resources Association, 1–21. https://doi.org/10.1111/1752-1688.12916

Analytical Chemistry Of Plastic Debris: Sampling, Methods, And Instrumentation, Robert C. Hale, Meredith E. Seeley, Ashley E. King, Lehuan H. Yu

VIMS Books and Book Chapters

Approaches for the collection and analysis of plastic debris in environmental matrices are rapidly evolving. Such plastics span a continuum of sizes, encompassing large (macro-), medium (micro-, typically defined as particles between 1 μm and 5 mm), and smaller (nano-) plastics. All are of environmental relevance. Particle sizes are dynamic. Large plastics may fragment over time, while smaller particles may agglomerate in the field. The diverse morphologies (fragment, fiber, sphere) and chemical compositions of microplastics further complicate their characterization. Fibers are of growing interest and present particular analytical challenges due to their narrow profiles. Compositional classes of emerging concern include …

Epidemic Spread Modeling For Covid-19 Using Hard Data, Anna Schmedding

Dissertations, Theses, and Masters Projects

We present an individual-centric model for COVID-19 spread in an urban setting. We first analyze patient and route data of infected patients from January 20, 2020 ,to May 31, 2020, collected by the Korean Center for Disease Control & Prevention (KCDC) and illustrate how infection clusters develop as a function of time. This analysis offers a statistical characterization of mobility habits and patterns of individuals. We use this characterization to parameterize agent-based simulations that capture the spread of the disease, we evaluate simulation predictions with ground truth, and we evaluate different what-if counter-measure scenarios. Although the presented agent-based model is …

Proton Spin Structure From Simultaneous Monte Carlo Global Qcd Analysis, Yiyu Zhou

Dissertations, Theses, and Masters Projects

Despite the great effort and achievements made towards understanding proton spin structure in the past few decades, a complete picture is still elusive. Parton distribution functions (PDFs), which in quantum chromodynamics (QCD) encode the momentum and helicity distributions of quarks and gluons inside a proton, provide the means by which to quantify the proton structure information. Being inherently nonperturbative, PDFs have to be extracted from unpolarized and polarized lepton-hadron and hadron-hadron scattering data. In particular, experiments that measure unpolarized and polarized jet observables can provide insight into the momentum and helicity distributions of gluons, which have generally been more difficult …

Combining Performance Profiling And Modeling For Accuracy And Efficiency, Hao Xu

Dissertations, Theses, and Masters Projects

Modern computer systems have evolved to employ powerful parallel architectures, including multi-core processors, multi-socket chips, large memory subsystems, and fast network communication. Given such powerful hardware, developers rely on performance profiling and modeling to guide their performance optimization. However, performance optimization is facing new challenges on efficiency and accuracy with emerging computer systems. In this dissertation, we propose approaches to address these challenges. We first study memory contention in Non-Uniform Memory Access (NUMA) architectures. We present DR-BW, a new tool based on machine learning to identify bandwidth contention in NUMA architectures and provide optimization guidance. DR-BW collects performance data with …

Indoor Chemistry: Development Of An Indoor Surface Extractor, Hannah Rose Przelomski

Dissertations, Theses, and Masters Projects

People spend around 90% of their time indoors. This means that indoor air can have an impact on human health. One of the main factors that makes indoor air differ from outdoor air is indoor areas have a higher surface area to volume ratio than outdoor areas. Surfaces give aerosol particles a place to deposit where they can stick or react. Some of this material can leave the surface and reenter the air. Being able to analyze the material on different indoor surfaces will help further the understanding of indoor surfaces’ impact on indoor air. A surface extractor was developed …

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 …

Sea Level-Driven Marsh Migration Results In Rapid Net Loss Of Carbon, Alexander J. Smith, Matthew L. Kirwan

VIMS Articles

Sea level rise alters coastal carbon cycling by driving the rapid migration of coastal ecosystems, salinization of freshwater systems, and replacement of terrestrial forests with tidal wetlands. Wetland soils accumulate carbon (C) at faster rates than terrestrial soils, implying that sea level rise may lead to enhanced carbon accumulation. Here, we show that carbon stored in tree biomass greatly exceeds carbon stored in adjacent marsh soils so that marsh migration reduces total carbon stocks by 50% in less than 100years. Continued marsh soil carbon accumulation may eventually offset forest carbon loss, but we estimate that the time for replacement is …

Sea-Ice Microbial Communities In The Central Arctic Ocean: Limited Responses To Short-Term Pco(2) Perturbations, Anders Torstensson, Andrew R. Margolin, Gordon M. Showalter, Walker O. Smith Jr., Elizabeth H. Shadwick, Et Al

VIMS Articles

The Arctic Ocean is more susceptible to ocean acidification than other marine environments due to its weaker buffering capacity, while its cold surface water with relatively low salinity promotes atmospheric CO 2 uptake. We studied how sea-ice microbial communities in the central Arctic Ocean may be affected by changes in the carbonate system expected as a consequence of ocean acidification. In a series of four experiments during late summer 2018 aboard the icebreaker Oden, we addressed microbial growth, production of dissolved organic carbon (DOC) and extra- cellular polymeric substances (EPS), photosynthetic activity, and bacterial assemblage structure as sea-ice microbial communities …

The Importance Of Organic Content To Fractal Floc Properties In Estuarine Surface Waters: Insights From Video, Lisst, And Pump Sampling, Kelsey A. Fall, Carl T. Friedrichs, Grace M. Massey, David G. Bowers, S. Jarrell Smith

VIMS Articles

To better understand the nature of flocs of varying organic content in estuarine surface waters, Laser in situ Scattering and Transmissometry, video settling, and pump sampling were deployed in the York River estuary. A new in situ method was developed to simultaneously solve the floc fractal dimension (F), primary particle size (d p ), and primary particle density (ρ p ) by fitting a simple fractal model to observations of effective floc density (∆ρ) as a function of floc diameter (d f ), while ensuring that the integrated particle size distribution was consistent with measurements of bulk apparent density (ρ …

Exchange Flow And Material Transport Along The Salinity Gradient Of A Long Estuary, Jilian Xiong, Jian Shen, Qubin Qin

VIMS Articles

Most estuaries are characterized by non-uniform axial topography with shallow shoals near the mouth. Previous studies have addressed the impacts of the axial topographic variations on mixing and estuarine circulations yet seldom on material transport and retention. This study investigates the longitudinal structure and mechanisms of exchange flow and material transport of Chesapeake Bay (CB), featuring a shallow sill in the lower bay, by applying total exchange flow (TEF) algorithm, tracer experiments, and partial residence time (PRT) using a validated 32-years numerical model simulation. A retention coefficient was adopted to quantify the material retention rate using two characteristic PRTs: with …

Large-Scale Variation In Wave Attenuation Of Oyster Reef Living Shorelines And The Influence Of Inundation Duration, Rebecca L. Morris, Megan K. Lapeyre, Bret M. Webb, Donna M. Bilkovic, Et Al

VIMS Articles

One of the paramount goals of oyster reef living shorelines is to achieve sustained and adaptive coastal protection, which requires meeting ecological (i.e., develop a self-sustaining oyster population) and engineering (i.e., provide coastal defense) targets. In a large-scale comparison along the Atlantic and Gulf coasts of the United States, the efficacy of various designs of oyster reef living shorelines at providing wave attenuation was evaluated accounting for the ecological limitations of oysters with regards to inundation duration. A critical threshold for intertidal oyster reef establishment is 50% inundation duration. Living shorelines that spent less than half of the time ( …

An Operational Overview Of The Export Processes In The Ocean From Remote Sensing (Exports) Northeast Pacific Field Deployment, David A. Siegel, Ivona Cetinic, (...), Deborah K. Steinberg, Et Al

VIMS Articles

The goal of the EXport Processes in the Ocean from RemoTe Sensing (EXPORTS) field campaign is to develop a predictive understanding of the export, fate, and carbon cycle impacts of global ocean net primary production. To accomplish this goal, observations of export flux pathways, plankton community composition, food web processes, and optical, physical, and biogeochemical (BGC) properties are needed over a range of ecosystem states. Here we introduce the first EXPORTS field deployment to Ocean Station Papa in the Northeast Pacific Ocean during summer of 2018, providing context for other papers in this special collection. The experiment was conducted with …

The Application Of Metacommunity Theory To The Management Of Riverine Ecosystems, Christopher J. Patrick, Kurt E. Anderson, Brown L. Brown, Et Al

VIMS Articles

River managers strive to use the best available science to sustain biodi versity and ecosystem function. T o achieve this goal requires consideration of processes at different scales. Metacommunity theory describes how multiple species from differ- ent communities potentially interact with local-scale environmental drivers to influ- ence population dynamics and community structure. However, this body of knowledge has only rarely been used to inform management practices for river ecosystems. In this article, we present a conceptual model outlining how the metacommunity processes of local niche sorting and dispersal can influence the outcomes of management interventions and provide a series of …

Global Blue Carbon Accumulation In Tidal Wetlands Increases With Climate Change, Faming Wang, Christian J. Sanders, (...), Matthew L. Kirwan, Et Al

VIMS Articles

Coastal tidal wetlands produce and accumulate significant amounts of organic carbon (C) that help to mitigate climate change. However, previous data limitations have prevented a robust evaluation of the global rates and mechanisms driving C accumulation. Here, we go beyond recent soil C stock estimates to reveal global tidal wetland C accumulation and predict changes under relative sea level rise, temperature and precipitation. We use data from literature study sites and our new observations spanning wide latitudinal gradients and 20 countries. Globally, tidal wetlands accumulate 53.65 (95%CI: 48.52–59.01) Tg C yr−1, which is∼30% of the organic C buried on the …

Migration Of The Tidal Marsh Range Under Sea Level Rise For Coastal Virginia, With Land Cover Data, Julie Herman, Molly Mitchell

Data

The layers in this geodatabase were intended to represent the land that is encompassed by the average tidal range as sea level rises in the Virginia coastal region, including Chesapeake Bay and tributaries, the Atlantic Ocean side of the Eastern Shore, and Virginia Beach. The data layers in this geodatabase represent each two foot range of elevation incremented by 0.5 ft (e.g. 0-2 ft, 0.5-2.5 ft, 1-3 ft, etc.) with the current land cover that exists in that range.

ArcGIS metadata is included in the geodatabase.

Further details are provided in the Geodatabase Information file located from the download tab.

Gis Data: Calvert County, Maryland - Shoreline Inventory Data 2020, Karinna Nunez, Marcia Berman, Sharon Killeen, Jessica Hendricks, Tamia Rudnicky, Catherine Riscassi

Data

The shoreline inventory files have been generated to support the application of the Maryland Shoreline Stabilization Model (SSM), developed by the Center for Coastal Resources Management (CCRM), Virginia Institute of Marine Science (VIMS), to enhance and streamline regulatory decision making in Maryland. This shoreline inventory includes the features needed as inputs to run the SSM.

The data developed for the Shoreline Inventory is based on a three-tiered shoreline assessment approach. This assessment characterizes conditions by using observations made remotely at the desktop using high resolution imagery. The three-tiered shoreline assessment approach divides the shorezone into three regions:

1) the immediate …

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

Data

This data repository is a permanent archive of the results presented in the associated publication (Turner et al. 2020, Science of the Total Environment, doi: 10.1016/j.scitotenv.2021.145157).

The objective of this study was to investigate the effects of shoreline erosion on water clarity in the Chesapeake Bay. To this end, we used the Chesapeake Bay ROMS Estuarine Carbon and Biogeochemistry (ChesROMS-ECB), a biogeochemical model embedded in the Regional Ocean Modeling System (ROMS). Using this model, we simulated a Chesapeake Bay estuary from 2001-2005 with varying magnitudes of sediment inputs from shoreline erosion and varying seabed erodibility conditions. Model results were compared …