Physical Sciences and Mathematics Commons^™

Contrasting Hydrodynamic Responses To Atmospheric Systems With Different Scales: Impact Of Cold Fronts Vs. That Of A Hurricane, Wei Huang, C. Li

VIMS Articles

In this paper, subtidal responses of Barataria Bay to an atmospheric cold front in 2014 and Hurricane Barry of 2019 are studied. The cold fronts had shorter influencing periods (1 to 3 days), while Hurricane Barry had a much longer influencing period (about 1 week). Wind direction usually changes from southern quadrants to northern quadrants before and after a cold front’s passage. For a hurricane making its landfall at the norther Gulf of Mexico coast, wind variation is dependent on the location relative to the location of landfall. Consequently, water level usually reaches a trough after the maximum cold front …

A Modeling Study On The Influence Of Sea-Level Rise And Channel Deepening On Estuarine Circulation And Dissolved Oxygen Levels In The Tidal James River, Virginia, Usa, Ya Wang, Jian Shen

VIMS Articles

The impact of channel deepening and sea-level rise on the environmental integrity of an estuary is investigated using a three-dimensional hydrodynamic-eutrophication model. The model results show that dissolved oxygen (DO) only experienced minor changes, even when the deep channel was deepened by 3 m in the mesohaline and polyhaline regions of the James River. We found that vertical stratification decreased DO aeration while the estuarine gravitational circulation increased bottom DO exchange. The interactions between these two processes play an important role in modulating DO. The minor change in DO due to channel deepening indicates that the James River is unique …

A Database Of Ocean Primary Productivity From The 14c Method, J. F. Marra, R. T. Barber, (...), Walker O. Smith Jr., L. Zoffli

VIMS Articles

The database on ocean primary productivity comprises over two decades (1985–2008) of data that the authors have participated in collecting, using the assimilation of inorganic ¹⁴C through photosynthesis, in incubations carried out in situ. The dataset is perhaps unique in that it uses, overwhelmingly, consistent methodology while covering a wide geographic range. Ancillary data are included. Using the database, it is hoped that investigators can test for the relationships among the environmental drivers for ocean productivity, the meaning of the ¹⁴C method in terms of phytoplankton physiology and the dynamics in the water column, and as a resource …

Ocean_Data_Tools: A Matlab Toolbox For Interacting With Bulk Freely-Available Oceanographic Data, Laur Ferris

VIMS Articles

ocean_data_tools simplifies the process of extracting, formatting, and visualizing freely-available oceanographic data. A wealth of oceanographic data (from research cruises, autonomous floats, global ocean models, etc.) is accessible online. However, many oceanographers and environmental scientists (particularly those from subdisciplines not accustomed to working with large datasets) can be dissuaded from utilizing this data because of the overhead associated with determining how to batch download data and format it into easily-manipulable data structures. ocean_data_tools solves this problem by allowing the user to transform common oceanographic data sources into uniform structure arrays, call general functions on these structure arrays, perform custom calculations, …

Climate-Induced Variability In South Atlantic Wave Direction Over The Past Three Millennia, A. P. Silva, A. H. F. Klein, A. F. H. Fetter-Filho, Christopher J. Hein, Et Al

VIMS Articles

Through alteration of wave-generating atmospheric systems, global climate changes play a fundamental role in regional wave climate. However, long-term wave-climate cycles and their associated forcing mechanisms remain poorly constrained, in part due to a relative dearth of highly resolved archives. Here we use the morphology of former shorelines preserved in beach-foredune ridges (BFR) within a protected embayment to reconstruct changes in predominant wave directions in the Subtropical South Atlantic during the last ~ 3000 years. These analyses reveal multi-centennial cycles of oscillation in predominant wave direction in accordance with stronger (weaker) South Atlantic mid- to high-latitudes mean sea-level pressure gradient …

How Old Are Marshes On The East Coast, Usa? Complex Patterns In Wetland Age Within And Among Regions, Anna E. Braswell, James B. Heffernan, Matthew L. Kirwan

VIMS Articles

Sea‐level dynamics, sediment availability, and marine energy are critical drivers of coastal wetland formation and persistence, but their roles as continental‐scale drivers remain unknown. We evaluated the timing and spatial variability of wetland formation from new and existing cores collected along the Atlantic and Gulf coasts of the United States. Most basal peat ages occurred after sea‐level rise slowed (after ~4,000 years before present), but predominance of sea‐level rise studies may skew age estimates toward older sites. Near‐coastal sites tended to be younger, indicating creation of wetlands through basin infilling and overwash events. Age distributions differed among regions, with younger …

Restoration Of Seagrass Habitat Leads To Rapid Recovery Of Coastal Ecosystem Services, Robert J. Orth, Jonathan S. Lefcheck, Karen S. Mcglathery, Lillian Aoki, Mark Luckenbach, Kenneth A. Moore, Matthew P.J. Oreska, Richard A. Snyder, David J. Wilcox, Bo Lusk

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There have been increasing attempts to reverse habitat degradation through active restoration, but few largescale successes are reported to guide these efforts. Here, we report outcomes from a unique and very successful seagrass restoration project: Since 1999, over 70 million seeds of a marine angiosperm, eelgrass (Zostera marina), have been broadcast into mid-western Atlantic coastal lagoons, leading to recovery of 3612 ha of seagrass. Well-developed meadows now foster productive and diverse animal communities, sequester substantial stocks of carbon and nitrogen, and have prompted a parallel restoration for bay scallops (Argopecten irradians). Restored ecosystem services are approaching historic levels, but we …

Effects Of Seawater Exchange On Water Chemistry Among Coastal Lakes With Intermittent Connections To The Sea, A. Challen Hyman, Dana Bigham Stephens

VIMS Articles

Intermittently closed and open lakes and lagoons (ICOLLs) are a dynamic class of coastal waterbodies with the unique feature of intermittently connecting to the sea. Understanding the functioning and potential threats of these globally rare systems is important to their preservation and protection. Coastal dune lakes of northwest Florida are one example of an understudied group of ICOLLs which connect with the Gulf of Mexico for brief periods of time. Using a 17-year, monthly water chemistry dataset, we analyzed long-term patterns in water chemistry among 16 coastal dune lakes. Using salinity as a proxy for frequency of seawater inflows, principal …

Volkilau: Volcano Rapid Response Balloon Campaign During The 2018 Kilauea Eruption, Jean Paul Vernier, Lars E. Kalnajs, Jorge Andrés Diaz, Tom Reese, Ernesto Corrales, Alfredo Alan, Hazel Vernier, Et Al

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After nearly 35 years of stable activity, the Kilauea volcanic system in Hawaii went through sudden changes in May 2018 with the emergence of 20 volcanic fissures along the Lower Eastern Rift Zone (LERZ), destroying 700 homes in Leilani Estates and forcing more than 2,000 people to evacuate. Elevated volcanic emissions lasted for several months between May and September 2018, leading to low visibility and poor air quality in Hawaii and across the western Pacific. The NASA-funded VolKilau mission was rapidly mounted and conducted between 11 and 18 June 2018 to (i) profile volcanic emissions with SO2 and aerosol measurements, …

A Continental Shelf Pump For Co2 On The Adélie Land Coast, East Antarctica, Mar C. Arroyo, Elizabeth H. Shadwick, Stephen R. Rintoul, Kazuya Kusahara

VIMS Articles

We quantify the transport of inorganic carbon from the continental shelf to the deep ocean in Dense Shelf Water (DSW) from the Mertz and Ninnis Polynyas along the Adélie Land coast in East Antarctica. For this purpose, observations of total dissolved inorganic carbon (TCO₂) from two summer hydrographic surveys in 2015 and 2017 were paired with DSW volume transport estimates derived from a coupled ocean‐sea ice‐ice shelf model to examine the fate of inorganic carbon in DSW from Adélie Land. Transports indicate a net outflow of 227 ± 115 Tg C yr⁻¹ with DSW in the postglacial …

Estuarine Forecasts At Daily Weather To Subseasonal Time Scales, Andrew C. Ross, Charles A. Stock, Keith W. Dixon, Marjorie A.M. Friedrichs, Et Al

VIMS Articles

Most present forecast systems for estuaries predict conditions for only a few days into the future. However, there are many reasons to expect that skillful estuarine forecasts are possible for longer time periods, including increasingly skillful extended atmospheric forecasts, the potential for lasting impacts of atmospheric forcing on estuarine conditions, and the predictability of tidal cycles. In this study, we test whether skillful estuarine forecasts are possible for up to 35 days into the future by combining an estuarine model of Chesapeake Bay with 35-day atmospheric forecasts from an operational weather model. When compared with both a hindcast simulation from …

Trace Metal Availability Affects Greenhouse Gas Emissions And Microbial Functional Group Abundance In Freshwater Wetland Sediments, George Giannopoulos, Katherine R. Hartop, Bonnie L. Brown, Bongkeun Song, Lars Elsgaard, Rima B. Franklin

VIMS Articles

We investigated the effects of trace metal additions on microbial nitrogen (N) and carbon (C) cycling using freshwater wetland sediment microcosms amended with micromolar concentrations of copper (Cu), molybdenum (Mo), iron (Fe), and all combinations thereof. In addition to monitoring inorganic N transformations (NO₃^–, NO₂^–, N₂O, NH₄⁺) and carbon mineralization (CO₂, CH₄), we tracked changes in functional gene abundance associated with denitrification (nirS, nirK, nosZ), dissimilatory nitrate reduction to ammonium (DNRA; nrfA), and methanogenesis (mcrA). With regards to …

Coastal Marsh Degradation Into Ponds Induces Irreversible Elevation Loss Relative To Sea Level In A Microtidal System, Lennert Schepers, Patrick Brennand, Matthew L. Kirwan, Glenn Guntenspergen, Stijn Temmerman

VIMS Articles

Coastal marshes and their valuable ecosystem services are feared to be lost by sea level rise, yet the mechanisms of marsh degradation into ponds and potential recovery are poorly understood. We quantified and analyzed elevations of marsh surfaces and pond bottoms along a marsh loss gradient (Blackwater River, Maryland, USA). Our analyses show that ponds deepen with increasing tidal channel width connecting the ponds to the river, indicating a new feedback mechanism where channels lead to enhanced tidal export of pond bottom material. Pond elevations also decrease with increasing pond size, consistent with previous work identifying a positive feedback between …

Modeling Marsh‐Forest Boundary Transgression In Response To Storms And Sea‐Level Rise, J. Carr, G. Guntenspergen, Matthew L. Kirwan

VIMS Articles

The lateral extent and vertical stability of salt marshes experiencing rising sea levels depend on interacting drivers and feedbacks with potential for nonlinear behaviors. A two‐dimensional transect model was developed to examine changes in marsh and upland forest lateral extent and to explore controls on marsh inland transgression. Model behavior demonstrates limited and abrupt forest retreat with long‐term upland boundary migration rates controlled by slope, sea‐level rise (SLR), high water events, and biotic‐abiotic interactions. For low to moderate upland slopes the landward marsh edge is controlled by the interaction of these inundation events and forest recovery resulting in punctuated transgressive …

What Drives Property Owners To Modify Their Shorelines? A Case Study Of Gloucester County, Virginia, Sarah Stafford, Amanda Guthrie

VIMS Articles

This analysis uses data from a survey of shoreline property owners combined with data on shoreline modification permits to examine whether and how property owners modify their estuarine shorelines. We find that shoreline armoring is very popular among property owners that choose to modify their shoreline. While living shorelines are less common, applications for them are increasing both in absolute numbers and as a percentage of all shoreline modification requests. A number of different issues factor into the shoreline modification decision including effectiveness, cost, aesthetics, and property values. More valuable parcels are more likely to be modified, as are parcels …

A Machine‐Learning‐Based Model For Water Quality In Coastal Waters, Taking Dissolved Oxygen And Hypoxia In Chesapeake Bay As An Example, Xin Yu, Jian Shen, Jiabi Du

VIMS Articles

Hypoxia is a big concern in coastal waters as it affects ecosystem health, fishery yield, and marine water resources. Accurately modeling coastal hypoxia is still very challenging even with the most advanced numerical models. A data‐driven model for coastal water quality is proposed in this study and is applied to predict the temporal‐spatial variations of dissolved oxygen (DO) and hypoxic condition in Chesapeake Bay, the largest estuary in the United States with mean summer hypoxic zone extending about 150 km along its main axis. The proposed model has three major components including empirical orthogonal functions analysis, automatic selection of forcing …

Data-Driven, Multi-Model Workflow Suggests Strong Influence From Hurricanes On The Generation Of Turbidity Currents In The Gulf Of Mexico, Courtney K. Harris, Jaia Syvitski, H. G. Arango, Et Al

VIMS Articles

Turbidity currents deliver sediment rapidly from the continental shelf to the slope and beyond; and can be triggered by processes such as shelf resuspension during oceanic storms; mass failure of slope deposits due to sediment- and wave-pressure loadings; and localized events that grow into sustained currents via self-amplifying ignition. Because these operate over multiple spatial and temporal scales, ranging from the eddy-scale to continental-scale; coupled numerical models that represent the full transport pathway have proved elusive though individual models have been developed to describe each of these processes. Toward a more holistic tool, a numerical workflow was developed to address …

Sediment Delivery To A Tidal Marsh Platform Is Minimized By Source Decoupling And Flux Convergence, Daniel J. Coleman, Neil K. Ganju, Matthew L. Kirwan

VIMS Articles

Sediment supply is a primary factor in determining marsh response to sea level rise and is typically approximated through high‐resolution measurements of suspended sediment concentrations (SSCs) from adjacent tidal channels. However, understanding sediment transport across the marsh itself remains limited by discontinuous measurements of SSC over individual tidal cycles. Here, we use an array of optical turbidity sensors to build a long‐term, continuous record of SSC across a marsh platform and adjacent tidal channel. We find that channel and marsh concentrations are correlated (i.e., coupled) within tidal cycles but are largely decoupled over longer time scales. We also find that …

Relative Impacts Of Global Changes And Regional Watershed Changes On The Inorganic Carbon Balance Of The Chesapeake Bay, Pierre St-Laurent, Marjorie A.M. Friedrichs, Raymond G. Najjar, Elizabeth Shadwick, Hanquin Tian, Yuanzhi Yao

VIMS Articles

The Chesapeake Bay is a large coastal-plain estuary that has experienced considerable anthropogenic changeover the past century. At the regional scale, land-use change has doubled the nutrient input from rivers and led to an increase in riverine carbon and alkalinity. The bay has also experienced global changes, including the rise of atmospheric temperature and CO2. Here we seek to understand the relative impact of these changes on the inorganic carbon balance of the bay between the early 1900s and the early 2000s. We use a linked land–estuarine–ocean modeling system that includes both inorganic and organic carbon and nitrogen cycling. Sensitivity …

Challenges In Quantifying Air‐Water Carbon Dioxide Flux Using Estuarine Water Quality Data: Case Study For Chesapeake Bay, Marie Herrmann, Raymond G. Najjar, Fei Da, Marjorie A.M. Friedrichs, Sreece Goldberger, Alana Menendez, Elizabeth Shadwick, Pierre St-Laurent

VIMS Articles

Estuaries play an uncertain but potentially important role in the global carbon cycle via CO₂ outgassing. The uncertainty mainly stems from the paucity of studies that document the full spatial and temporal variability of estuarine surface water partial pressure of carbon dioxide ( p CO₂). Here, we explore the potential of utilizing the abundance of pH data from historical water quality monitoring programs to fill the data void via a case study of the mainstem Chesapeake Bay (eastern United States). We calculate p CO₂ and the air‐water CO₂ flux at monthly resolution from 1998 to …

Flame Retardants, Dioxins, And Furans In Air And On Firefighters’ Protective Ensembles During Controlled Residential Firefighting, Kenneth W. Fent, Mark J. La Guardia, Drew Luellen, Et Al

VIMS Articles

Structure fires that involve modern furnishings may emit brominated flame retardants (BFRs) and organophosphate flame retardants (OPFRs), as well as brominated and chlorinated dioxins and furans, into the environment.

The goal of this study was to quantify the airborne and personal protective equipment (PPE) contamination levels of these compounds during controlled residential fires in the U.S., and to evaluate gross-decontamination measures.

Single-Use Plastics And Covid-19: Scientific Evidence And Environmental Regulations, Robert C. Hale, Bk Song

VIMS Articles

Waste plastics are a serious and growing environmental problem. Less than 10% of plastics are recycled, with most discarded in landfills, incinerated, or simply abandoned.1 Single-use plastics constitute about half of plastic waste. While most plastics are used and initially disposed of on land, much eventually enters aquatic ecosystems.2 Wildlife mortalities result from encounters (e.g., ingestion and entanglement) with large debris, including plastic bags. Such bags are excluded from many recycling programs, as they can entangle machinery. Most plastics do not readily biodegrade in the environment. However, they can be embrittled by UV exposure and fragment into microplastics (mm) and …

Zooplankton Diel Vertical Migration During Antarctic Summer, John A. Conroy, Deborah K. Steinberg, Patrica S. Thibodeau, Oscar Schofield

VIMS Articles

Zooplankton diel vertical migration (DVM) during summer in the polar oceans is presumed to be dampened due to near continuous daylight. We analyzed zooplankton diel vertical distribution patterns in a wide range of taxa along the Western Antarctic Peninsula (WAP) to assess if DVM occurs, and if so, what environmental controls modulate DVM in the austral summer. Zooplankton were collected during January and February in paired day-night, depth-stratified tows through the mesopelagic zone along the WAP from 2009-2017, as well as in day and night epipelagic net tows from 1993-2017. The copepod Metridia gerlachei, salp Salpa thompsoni, pteropod …

Constraining An Ocean Model Under Getz Ice Shelf, Antarctica, Using A Gravity‐Derived Bathymetry, Romain Millan, Pierre St-Laurent, Eric Rignot, Et Al

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Getz Ice Shelf, the largest producer of ice shelf meltwater in Antarctica, buttresses glaciers that hold enough ice to raise sea level by 22 cm. We present a new bathymetry of its sub‐ice shelf cavity using a three‐dimensional inversion of airborne gravity data constrained by multibeam bathymetry at sea and a reconstruction of the bedrock from mass conservation on land. The new bathymetry is deeper than previously estimated with differences exceeding 500 m in a number of regions. When incorporated into an ocean model, it yields a better description of the spatial distribution of ice shelf melt, specifically along glacier …

Current And Future Remote Sensing Of Harmful Algal Blooms In The Chesapeake Bay To Support The Shellfish Industry, Jl Wolny, Mc Tomlinson, S Schollaert Uz, Ta Egerton, Jr Mckay, A Meredith, Ks Reece, Gp Scott, Rp Stumpf

VIMS Articles

Harmful algal bloom (HAB) species in the Chesapeake Bay can negatively impact fish, shellfish, and human health via the production of toxins and the degradation of water quality. Due to the deleterious effects of HAB species on economically and environmentally important resources, such as oyster reef systems, Bay area resource managers are seeking ways to monitor HABs and water quality at large spatial and fine temporal scales. The use of satellite ocean color imagery has proven to be a beneficial tool for resource management in other locations around the world where high-biomass, nearly monospecific HABs occur. However, remotely monitoring HABs …

The Impact Of Winter Storms On Sediment Transport Through A Narrow Strait, Bohai, China, Chenghao Wang, Zhiqiang Liu, Courtney K. Harris, Et Al

VIMS Articles

The Yellow River is one of the most significant sources of terrestrial sediment to the global seas, and the Bohai Strait is the only pathway that delivers Yellow River‐derived sediments from the shallow Bohai Sea to the Yellow Sea. To investigate sediment transport processes through the strait under the influence of storms (strong northerly winds) that frequently occur in winter, we deployed two sets of observing platforms equipped with Acoustic Doppler Current Profilers (ADCP) and a suite of other sensors in the strait in January 2018. Aided by a system of high‐resolution models, we reconstructed sediment dynamics in response to …

Representing The Function And Sensitivity Of Coastal Interfaces In Earth System Models, Nd Ward, Jp Megonigal, B Bond-Lamberty, Vl Bailey, D Butman, Elizabeth A. Canuel, Et Al

VIMS Articles

Between the land and ocean, diverse coastal ecosystems transform, store, and transport material. Across these interfaces, the dynamic exchange of energy and matter is driven by hydrological and hydrodynamic processes such as river and groundwater discharge, tides, waves, and storms. These dynamics regulate ecosystem functions and Earth's climate, yet global models lack representation of coastal processes and related feedbacks, impeding their predictions of coastal and global responses to change. Here, we assess existing coastal monitoring networks and regional models, existing challenges in these efforts, and recommend a path towards development of global models that more robustly reflect the coastal interface. …

Providential Tides: The Double Low Water Of Narragansett Bay, D. G. Bowers, J. M. Brubaker

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We investigate a mechanism for producing double-lows and double-highs in the semi-diurnal tide by selective amplification of higher harmonics in a resonant gulf. A double low water is observed at Providence, RI, near the head of Narragansett Bay on days when there is a flattening of the low water tidal curve at Newport, at the mouth of the bay. The flattening is caused by an unusually large quarter-diurnal component to the tide at Newport. The quarter diurnal component has the right phase (a maximum close to the time of the minimum in the semi-diurnal tide) to produce a prolonged flattening …

Massive Pollutants Released To Galveston Bay During Hurricane Harvey: Understanding Their Retention And Pathway Using Lagrangian Numerical Simulations, Jiabi Du, Kyeong Park, Xin Yu, Yinglong J. Zhang, Fei Ye

VIMS Articles

Increasing frequency of extreme precipitation events under the future warming climate makes the storm-related pollutant release more and more threatening to coastal ecosystems. Hurricane Harvey, a 1000-year extreme precipitation event, caused massive pollutant release from the Houston metropolitan area to the adjacent Galveston Bay. 0.57 × 10⁶ tons of raw sewage and 22,000 barrels of oil, refined fuels and chemicals were reportly released during Harvey, which would likely deteriorate the water quality and damage the coastal ecosystem. Using a Lagrangian particle-tracking method coupled with a validated 3D hydrodynamic model, we examined the retention, pathway, and fate of the released …

Response Of Stratification Processes To Tidal Current Alteration Due To Channel Narrowing And Deepening, Lei Zhu, Qing He, Jian Shen

VIMS Articles

Stratification in estuaries has received much focus due to its importance in estuarine hydrodynamics and material transport. By utilizing a well‐calibrated numerical model, in this work we investigate the changes in stratification in the deepened and narrowed North Passage of the Changjiang Estuary. Before channel narrowing and deepening, lateral straining, generated by the interaction between vertical shear in lateral flow and transverse salinity gradient, is the dominant factor that controls stratification. A two‐layer structure of the lateral flow strains the isopycnal transversely, resulting in rapid stratification from late flood to early ebb tide. Thus, maximum stratification occurs during the early …