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VIMS Articles

2019

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Articles 31 - 44 of 44

Full-Text Articles in Physical Sciences and Mathematics

A Data-Driven Modeling Approach For Simulating Algal Blooms In The Tidal Freshwater Of James River In Response To Riverine Nutrient Loading, Jian Shen, Qubin Qin, Ya Wang, Mac Sisson Apr 2019

A Data-Driven Modeling Approach For Simulating Algal Blooms In The Tidal Freshwater Of James River In Response To Riverine Nutrient Loading, Jian Shen, Qubin Qin, Ya Wang, Mac Sisson

VIMS Articles

Algal blooms often occur in the tidal freshwater (TF) of the James River estuary, a tributary of the Chesapeake Bay. The timing of algal blooms correlates highly to a summer low-flow period when residence time is long and nutrients are available. Because of complex interactions between physical transport and algal dynamics, it is challenging to predict interannual variations of bloom correctly using a complex eutrophication model without having ahigh-resolution model gridto resolve complexgeometryand anaccurate estimate of nutrientloading to drive the model. In this study, an approach using long-term observational data (from 1990 to 2013) and the Support vector machine (LS-SVM) …


Modeling Iron And Light Controls On The Summer Phaeocystis Antarctica Bloom In The Amundsen Sea Polynya, H Oliver, Pierre St-Laurent, Rm Sherrell, Pl Yager Apr 2019

Modeling Iron And Light Controls On The Summer Phaeocystis Antarctica Bloom In The Amundsen Sea Polynya, H Oliver, Pierre St-Laurent, Rm Sherrell, Pl Yager

VIMS Articles

Of all the Antarctic coastal polynyas, the Amundsen Sea Polynya is the most productive per unit area. Observations from the 2010–2011 Amundsen Sea Polynya International Research Expedition (ASPIRE) revealed that both light and iron can limit the growth of phytoplankton (Phaeocystis antarctica), but how these controls manifest over the bloom season is poorly understood, especially with respect to their climate sensitivity. Using a 1‐D biogeochemical model, we examine the influence of light and iron limitation on the phytoplankton bloom and vertical carbon flux at 12 stations representing different bloom stages within the polynya. Model parameters are determined by …


Variability And Change In The West Antarctic Peninsula Marine System: Research Priorities And Opportunities, Sian F. Henley, Oscar M. Schofield, Katherine R. Hendry, Irene R. Schloss, Deborah K. Steinberg, Et Al Apr 2019

Variability And Change In The West Antarctic Peninsula Marine System: Research Priorities And Opportunities, Sian F. Henley, Oscar M. Schofield, Katherine R. Hendry, Irene R. Schloss, Deborah K. Steinberg, Et Al

VIMS Articles

The west Antarctic Peninsula (WAP) region has undergone significant changes in temperature and seasonal ice dynamics since the mid-twentieth century, with strong impacts on the regional ecosystem, ocean chemistry and hydrographic properties. Changes to these long-term trends of warming and sea ice decline have been observed in the 21st century, but their consequences for ocean physics, chemistry and the ecology of the high-productivity shelf ecosystem are yet to be fully established. The WAP shelf is important for regional krill stocks and higher trophic levels, whilst the degree of variability and change in the physical environment and documented biological and biogeochemical …


Advancing Marine Biogeochemical And Ecosystem Reanalyses And Forecasts As Tools For Monitoring And Managing Ecosystem Health, K Fennel, M Gehlen, P Brasseur, Cw Brown, C Ciavatta, G Cossarini, A Crise, Ca Edwards, D Ford, Marjorie A.M. Friedrichs, Et Al Mar 2019

Advancing Marine Biogeochemical And Ecosystem Reanalyses And Forecasts As Tools For Monitoring And Managing Ecosystem Health, K Fennel, M Gehlen, P Brasseur, Cw Brown, C Ciavatta, G Cossarini, A Crise, Ca Edwards, D Ford, Marjorie A.M. Friedrichs, Et Al

VIMS Articles

Ocean ecosystems are subject to a multitude of stressors, including changes in ocean physics and biogeochemistry, and direct anthropogenic influences. Implementation of protective and adaptive measures for ocean ecosystems requires a combination of ocean observations with analysis and prediction tools. These can guide assessments of the current state of ocean ecosystems, elucidate ongoing trends and shifts, and anticipate impacts of climate change and management policies. Analysis and prediction tools are defined here as ocean circulation models that are coupled to biogeochemical or ecological models. The range of potential applications for these systems is broad, ranging from reanalyses for the assessment …


Modeling The Seasonal Cycle Of Iron And Carbon Fluxes In The Amundsen Sea Polynya, Antarctica, P. St-Laurent, Pl Yager, Rm Sherrell, H. Oliver, Ms Dinniman, Se Stammerjohn Feb 2019

Modeling The Seasonal Cycle Of Iron And Carbon Fluxes In The Amundsen Sea Polynya, Antarctica, P. St-Laurent, Pl Yager, Rm Sherrell, H. Oliver, Ms Dinniman, Se Stammerjohn

VIMS Articles

The Amundsen Sea Polynya (ASP) is distinguished by having the highest net primary production per unit area in the coastal Antarctic. Recent studies have related this high productivity to the presence of fast-melting ice shelves, but the mechanisms involved are not well understood. In this study we describe the first numerical model of the ASP to represent explicitly the ocean-ice interactions, nitrogen and iron cycles, and the coastal circulation at high resolution. The study focuses on the seasonal cycle of iron and carbon, and the results are broadly consistent with field observations collected during the summer of 2010–2011. The simulated …


Ocean Circulation Causes Strong Variability In The Mid-Atlantic Bight Nitrogen Budget, Marjorie A.M. Friedrichs, Pierre St-Laurent, Yongjin Xiao, Et Al Jan 2019

Ocean Circulation Causes Strong Variability In The Mid-Atlantic Bight Nitrogen Budget, Marjorie A.M. Friedrichs, Pierre St-Laurent, Yongjin Xiao, Et Al

VIMS Articles

Portions of the ocean adjacent to land masses play a particularly important role in global nutrient cycling; however, strong spatial and temporal variability in these shallow regions of the ocean make it difficult to quantify nitrogen fluxes from observations alone. Here we use a computer simulation to estimate the fluxes and transformations of inorganic and organic nitrogen in Mid-Atlantic U.S. coastal waters. The coastal circulation flows southward providing roughly two thirds of the inorganic nitrogen to this region, with the remaining third entering from rivers and estuaries. Nitrogen transport across the continental slope is highly variable, directed into the system …


Pattern And Scale: Evaluating Generalities In Crab Distributions And Marsh Dynamics From Small Plots To A National Scale, K Wasson, K Raposa, Et Al, David S. Johnson, Scott Lerberg, Et Al Jan 2019

Pattern And Scale: Evaluating Generalities In Crab Distributions And Marsh Dynamics From Small Plots To A National Scale, K Wasson, K Raposa, Et Al, David S. Johnson, Scott Lerberg, Et Al

VIMS Articles

The generality of ecological patterns depends inextricably on the scale at which they are examined. We investigated patterns of crab distribution and the relationship between crabs and vegetation in salt marshes at multiple scales. By using consistent monitoring protocols across 15 U.S. National Estuarine Research Reserves, we were able to synthesize patterns from the scale of quadrats to the entire marsh landscape to regional and national scales. Some generalities emerged across marshes from our overall models, and these are useful for informing broad coastal management policy. We found that crab burrow distribution within a marsh could be predicted by marsh …


High-Frequency Co2-System Variability Over The Winter-To-Spring Transition In A Large Coastal Plain Estuary, Elizabeth H. Shadwick, Marjorie A.M. Friedrichs, Raymond G. Najjar, Olivia A. De Meo, Jaclyn R. Friedman, Fei Da, W. G. Reay Jan 2019

High-Frequency Co2-System Variability Over The Winter-To-Spring Transition In A Large Coastal Plain Estuary, Elizabeth H. Shadwick, Marjorie A.M. Friedrichs, Raymond G. Najjar, Olivia A. De Meo, Jaclyn R. Friedman, Fei Da, W. G. Reay

VIMS Articles

Understanding the vulnerability of estuarine ecosystems to anthropogenic impacts requires a quantitative assessment of the dynamic drivers of change to the carbonate (CO2) system. Here we present new high‐frequency pH data from a moored sensor. These data are combined with discrete observations to create continuous time series of total dissolved inorganic carbon (TCO2), CO2 partial pressure (pCO2), and carbonate saturation state. We present two deployments over the winter‐to‐spring transition in the lower York River (where it meets the Chesapeake Bay mainstem) in 2016/2017 and 2017/2018. TCO2 budgets with daily resolution are constructed, …


Projections Of Atmospheric Nitrogen Deposition To The Chesapeake Bay Watershed, Patrick C. Campbell, Jesse O. Bash, Christopher G. Nolte, Tanya L. Spero, Ellen J. Cooter, Kyle Hinson, Lewis C. Linker Jan 2019

Projections Of Atmospheric Nitrogen Deposition To The Chesapeake Bay Watershed, Patrick C. Campbell, Jesse O. Bash, Christopher G. Nolte, Tanya L. Spero, Ellen J. Cooter, Kyle Hinson, Lewis C. Linker

VIMS Articles

Atmospheric deposition is among the largest pathways of nitrogen loading to the Chesapeake Bay Watershed (CBW). The interplay between future climate and emission changes in and around the CBW will likely shift the future nutrient deposition abundance and chemical regime (e.g., oxidized vs. reduced nitrogen). In this work, a Representative Concentration Pathway from the Community Earth System Model is dynamically downscaled using a recently updated Weather Research and Forecasting model that subsequently drives the Community Multiscale Air Quality model coupled to the agroeconomic Environmental Policy Integrated Climate model. The relative impacts of emission and climate changes on atmospheric nutrient deposition …


The Future Of Coastal And Estuarine Modeling: Findings From A Workshop, Oliver B. Fringer, Clint N. Dawson, Ruoying He, David K. Ralston, Yinglong J. Zhang Jan 2019

The Future Of Coastal And Estuarine Modeling: Findings From A Workshop, Oliver B. Fringer, Clint N. Dawson, Ruoying He, David K. Ralston, Yinglong J. Zhang

VIMS Articles

This paper summarizes the findings of a workshop convened in the United States in 2018 to discuss methods in coastal and estuarine modeling and to propose key areas of research and development needed to improve their accuracy and reliability. The focus of this paper is on physical processes, and we provide an overview of the current state-of-the-art based on presentations and discussions at the meeting, which revolved around the four primary themes of parameterizations, numerical methods, in-situ and remote-sensing measurements,and high-performance computing. A primary outcome of the workshop was agreement on the need to reduce subjectivity and improve reproducibility in …


Summer Carbonate Chemistry In The Dalton Polynya, East Antarctica, Mc Arroyo, Eh Shadwick, B Tilbrook Jan 2019

Summer Carbonate Chemistry In The Dalton Polynya, East Antarctica, Mc Arroyo, Eh Shadwick, B Tilbrook

VIMS Articles

The carbonate chemistry in the Dalton Polynya in East Antarctica (115°–123°E) was investigated in summer 2014/2015 using high‐frequency underway measurements of CO2 fugacity (fCO2) and discrete water column measurements of total dissolved inorganic carbon (TCO2) and total alkalinity. Air‐sea CO2 fluxes indicate this region was a weak net source of CO2 to the atmosphere (0.7 ± 0.9 mmol C m−2 day−1) during the period of observation, with the largest degree of surface water supersaturation (ΔfCO2 = +45 μatm) in ice‐covered waters near the Totten Ice Shelf (TIS) as compared to the ice‐free surface waters in the Dalton Polynya. The seasonal …


Alkalinity In Tidal Tributaries Of The Chesapeake Bay, R. G. Najjar, M. Herrmann, S. M. Cintrón Del Valle, Jaclyn R. Friedman, Marjorie A.M. Friedrichs, Et Al Jan 2019

Alkalinity In Tidal Tributaries Of The Chesapeake Bay, R. G. Najjar, M. Herrmann, S. M. Cintrón Del Valle, Jaclyn R. Friedman, Marjorie A.M. Friedrichs, Et Al

VIMS Articles

Despite the important role of alkalinity in estuarine carbon cycling, the seasonal and decadal variability of alkalinity, particularly within multiple tidal tributaries of the same estuary, is poorly understood. Here we analyze more than 25,000 alkalinity measurements, mostly from the 1980s and 1990s,in the major tidal tributaries of the Chesapeake Bay, a large, coastal‐plain estuary of eastern North America.The long‐term means of alkalinity in tidal‐fresh waters vary by a factor of 6 among seven tidal tributaries,reflecting the alkalinity of nontidal rivers draining to these estuaries. At 25 stations, mostly in the Potomac River Estuary, wefind significant long‐term increasing trends that …


Embracing Dynamic Design For Climate-Resilient Living Shorelines, Molly Mitchell, Donna M. Bilkovic Jan 2019

Embracing Dynamic Design For Climate-Resilient Living Shorelines, Molly Mitchell, Donna M. Bilkovic

VIMS Articles

As natural marshes are lost to erosion, sea level rise, and human activity, small created marshes, (sometimes with ancillary stabilization structures, and frequently called living shorelines) have gained interest as a replacement habitat; providing both shoreline stabilization and restoration of important ecological functions. These living shorelines enhance ecological function while reducing erosion through the use of marsh plants (Table 1). In all but the lowest energy settings, oyster reefs, low rock structures, or other stabilizing material are frequently used to enhance marsh establishment. Due to their ability to stabilize the shoreline with minimal impact to the ecology, living shorelines are …


Ocean Change Within Shoreline Communities: From Biomechanics To Behaviour And Beyond, Brian Gaylord, Kristina M. Barclay, Brittany M. Jellison, Laura L. Jurgens, Aaron T. Ninokawa, Emily B. Rivest, Lindsey R. Leighton Jan 2019

Ocean Change Within Shoreline Communities: From Biomechanics To Behaviour And Beyond, Brian Gaylord, Kristina M. Barclay, Brittany M. Jellison, Laura L. Jurgens, Aaron T. Ninokawa, Emily B. Rivest, Lindsey R. Leighton

VIMS Articles

Humans are changing the physical properties of Earth. In marine systems, elevated carbon dioxide concentrations are driving notable shifts in temperature and seawater chemistry. Here, we consider consequences of such perturbations for organism biomechanics and linkages amongst species within communities.In particular,we examine case examples of altered morphologies and material properties, disrupted consumer–prey behaviours, and the potential for modulated positive (i.e. facilitative) interactions amongst taxa, as incurred through increasing ocean acidity and rising temperatures. We focus on intertidal rocky shores of temperate seas as model systems, acknowledging the longstanding role of these communities in deciphering ecological principles. Our survey illustrates the …