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Full-Text Articles in Physical Sciences and Mathematics

Net Primary Productivity Estimates And Environmental Variables In The Arctic Ocean; An Assessment Of Coupled Physical-Biogeochemical Models, Younjoo J. Lee, Patrica A. Matrai, Marjorie A.M. Friedrichs, Et Al Dec 2016

Net Primary Productivity Estimates And Environmental Variables In The Arctic Ocean; An Assessment Of Coupled Physical-Biogeochemical Models, Younjoo J. Lee, Patrica A. Matrai, Marjorie A.M. Friedrichs, Et Al

VIMS Articles

The relative skill of 21 regional and global biogeochemical models was assessed in terms of how well the models reproduced observed net primary productivity (NPP) and environmental variables such as nitrate concentration (NO (sub 3) ), mixed layer depth (MLD), euphotic layer depth (Z (sub eu) ), and sea ice concentration, by comparing results against a newly updated, quality-controlled in situ NPP database for the Arctic Ocean (1959-2011). The models broadly captured the spatial features of integrated NPP (iNPP) on a pan-Arctic scale. Most models underestimated iNPP by varying degrees in spite of overestimating surface NO (sub 3) , MLD, …


Street-Level Inundation Modeling Of Hurricanes Matthew And Hermine And Emerging Flood Monitoring Methods In Hampton Roads, Jon Derek Loftis, H. V. Wang, D R. Forrest Nov 2016

Street-Level Inundation Modeling Of Hurricanes Matthew And Hermine And Emerging Flood Monitoring Methods In Hampton Roads, Jon Derek Loftis, H. V. Wang, D R. Forrest

Presentations

No abstract provided.


Evaluation Of The Potential Impact On Flow And Sediment Transport From Proposed James River Crossings, Yinglong J. Zhang, Harry V. Wang, Zhuo Liu, Mac Sisson, Jian Shen Oct 2016

Evaluation Of The Potential Impact On Flow And Sediment Transport From Proposed James River Crossings, Yinglong J. Zhang, Harry V. Wang, Zhuo Liu, Mac Sisson, Jian Shen

Reports

The purpose of this study is to evaluate the potential impact on flow and sedimentation potential due to the proposed new crossings on the lower James River by VDOT. This project was built upon previous effort in the same area (Boon et al. 1999); the latter used VIMS’ 3D Hydrodynamic-Sedimentation Model (HYSED) to study the impact of the bridge-tunnel infrastructure on the physical characteristics (including tides, currents, circulation, salinity and sedimentation) under the existing and alternative scenarios. Due to various limitations at that time, smaller bridge pilings were not resolved but instead parameterized. In this update study, we used an …


Sea-Level Rise & Virginia's Coastal Wetlands, Center For Coastal Resources Management, Virginia Institute Of Marine Science Jul 2016

Sea-Level Rise & Virginia's Coastal Wetlands, Center For Coastal Resources Management, Virginia Institute Of Marine Science

Reports

Rivers & Coast is a periodic publication of the Center for Coastal Resources Management, Virginia Institute of Marine Science. The goal of Rivers & Coast is to keep readers well informed of current scientific understanding behind key environmental issues related to watershed rivers and coastal ecosystems of the Chesapeake Bay.


A Hydrodynamic-Sediment Transport Numerical Model For The Waipaoa Shelf, New Zealand: Model Archive, Julia Moriarty, Courtney K. Harris, Mark G. Hadfield Apr 2016

A Hydrodynamic-Sediment Transport Numerical Model For The Waipaoa Shelf, New Zealand: Model Archive, Julia Moriarty, Courtney K. Harris, Mark G. Hadfield

Data

No abstract provided.


Nitrogen Sources And Net Growth Efficiency Of Zooplankton In Three Amazon River Plume Food Webs, Natalie Loick-Wilde, Sarah C. Weber, Brandon J. Condon, Douglas G. Capone, Victoria J. Coles, Patricia M. Medeiros, Deborah K. Steinberg, Joseph P. Montoya Mar 2016

Nitrogen Sources And Net Growth Efficiency Of Zooplankton In Three Amazon River Plume Food Webs, Natalie Loick-Wilde, Sarah C. Weber, Brandon J. Condon, Douglas G. Capone, Victoria J. Coles, Patricia M. Medeiros, Deborah K. Steinberg, Joseph P. Montoya

VIMS Articles

The plasticity of nitrogen specific net growth efficiency (NGE) in marine mesozooplankton is currently unresolved, with discordant lines of evidence suggesting that NGE is constant, or that it varies with nitrogen source, food availability, and food quality in marine ecosystems. Specifically, the fate of nitrogen from nitrogen fixation is poorly known. We use 15N : 14N ratios in plankton in combination with hydrological data, nutrient profiles, and nitrogen fixation rate measurements to investigate the relationship between new nitrogen sources and the nitrogen specific NGE in three plankton communities along the outer Amazon River plume. The NGE of small …


2016 Hampton Roads Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans Jan 2016

2016 Hampton Roads Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.


2016 Gloucester Point Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans Jan 2016

2016 Gloucester Point Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.


2016 Chesapeake Bay Bridge Tunnel Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans Jan 2016

2016 Chesapeake Bay Bridge Tunnel Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.


2016 Wachapreague Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans Jan 2016

2016 Wachapreague Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.


Modeling Phytoplankton Community Response To Nutrient Loading And Climate Change In A Shallow Temperate Estuary, Sara Aimee Blachman Jan 2016

Modeling Phytoplankton Community Response To Nutrient Loading And Climate Change In A Shallow Temperate Estuary, Sara Aimee Blachman

Dissertations, Theses, and Masters Projects

Phytoplankton account for at least half of all primary production in estuarine waters and are at the center of biogeochemical cycles and material budgets. Environmental managers use water column chlorophyll-a (chl-a) concentrations as a basic water quality indictor, as the problems of eutrophication and hypoxia are intrinsically linked to excessive phytoplankton growth. Evidence suggests that the distribution and frequency of harmful algal blooms may be increasing worldwide. For the most part, phytoplankton communities follow a standard seasonal pattern, with specific groups dominating the assemblage during the time of year when environmental conditions correspond to their requisites for growth. However, climate …


Zooplankton Community Composition And Grazing In The Amazon River Plume And Western Tropical North Atlantic Ocean, Brandon J. Conroy Jan 2016

Zooplankton Community Composition And Grazing In The Amazon River Plume And Western Tropical North Atlantic Ocean, Brandon J. Conroy

Dissertations, Theses, and Masters Projects

Large river plumes and frontal zones are important physical features influencing plankton distribution in the marine environment. In the western tropical North Atlantic Ocean (WTNA) the Amazon River plume may extend over an area reaching 1.5 x 106 km2. The freshwater plume creates a low-density lens in the surface 25m and supplies silicon and phosphorus to the WTNA. These physical and chemical gradients create an ideal environment for large-scale blooms of diatom diazotroph associations (DDAs), a symbiotic relationship between nitrogen-fixing cyanobacteria and chain-forming diatoms. While the physical and chemical properties of the plume with regard to influences on phytoplankton have …


Population Dynamics Of Gelatinous Zooplankton In The Chesapeake Bay And Sargasso Sea, And Effects On Carbon Export, Joshua Paul Stone Jan 2016

Population Dynamics Of Gelatinous Zooplankton In The Chesapeake Bay And Sargasso Sea, And Effects On Carbon Export, Joshua Paul Stone

Dissertations, Theses, and Masters Projects

Gelatinous zooplankton (GZ; cnidarians, ctenophores, and pelagic tunicates) periodically are the dominant members of the zooplankton throughout the majority of the world’s oceans. their unique body plans and life cycles allow them to rapidly take advantage of favorable environmental conditions, which has far-ranging consequences for food web dynamics and biogeochemical cycles. GZ populations have been speculated to respond to anthropogenic changes, but few long-term studies exist to test this hypothesis and even fewer have examined the consequent effects on carbon export. I analyzed two long-term time series in the Chesapeake Bay and one in the Sargasso Sea for annual and …


Combining Inverse And Transport Modeling To Estimate Bacterial Loading And Transport In A Tidal Embayment, Mac Sisson, Jian Shen, Anne Schlegel Jan 2016

Combining Inverse And Transport Modeling To Estimate Bacterial Loading And Transport In A Tidal Embayment, Mac Sisson, Jian Shen, Anne Schlegel

VIMS Articles

Poquoson River is a tidal coastal embayment located along the Western Shore of the Chesapeake Bay about 4 km south of the York River mouth in the City of Poquoson and in York County, Virginia. Its drainage area has diversified land uses, including high densities of residence, agricultural, salt marsh land uses, as well as a National Wildlife Refuge. This embayment experiences elevated bacterial concentration due to excess bacterial inputs from storm water runoff, nonpoint sources, and wash off from marshes due to tide and wind-induced set-up and set-down. Bacteria can also grow in the marsh and small tributaries. It …


Development Of The Hydrodynamic Model For Long-Term Simulation Of Water Quality Processes Of The Tidal James River, Virginia, Jian Shen, Ya Wang, Mac Sisson Jan 2016

Development Of The Hydrodynamic Model For Long-Term Simulation Of Water Quality Processes Of The Tidal James River, Virginia, Jian Shen, Ya Wang, Mac Sisson

VIMS Articles

Harmful algal blooms (HABs) have frequently occurred in the James River. The State has convened a Scientific Advisory Panel (SAP) to review the James River chlorophyll-a standards. The SAP will conduct a scientific study to review the basis for setting the chlorophyll-a standards. To support the SAP study of chlorophyll-a standards, the State of Virginia has decided to develop a numerical modeling system that is capable of simulating phytoplankton and HABs. The modeling system includes a watershed model, a three-dimensional hydrodynamic model and water quality models. The focus of this study will be on the development and verification of the …


A Comparative Study Of Iron And Temperature Interactive Effects On Diatoms And Phaeocystis Antarctica From The Ross Sea, Antarctica, Zhi Zhu, Kai Xu, Feixue Fu, Jenna L. Spackeen, Deborah A. Bronk, David A. Hutchins Jan 2016

A Comparative Study Of Iron And Temperature Interactive Effects On Diatoms And Phaeocystis Antarctica From The Ross Sea, Antarctica, Zhi Zhu, Kai Xu, Feixue Fu, Jenna L. Spackeen, Deborah A. Bronk, David A. Hutchins

VIMS Articles

In the future, temperature and iron availability are predicted to change in the coastal polynyas of Antarctica, which are the most biologically productive regions of the Southern Ocean. We examined the individual and combined effects of iron addition (+500 nM) and temperature increase (4°C) on Phaeocystis antarctica and several dominant diatom species isolated from the McMurdo Sound sector of the Ross Sea. Iron addition increased growth, carbon fixation, iron uptake rates, cellular carbon quota, and cell size of almost all tested species, while temperature increase only affected certain species. Concurrent increases in temperature and iron synergistically stimulated the growth rates …


A Carbon Budget For The Amundsen Sea Polynya, Antarctica: Estimating Net Community Production And Export In A Highly Productive Polar Ecosystem, Pl Yager, Rm Sherrell, Et Al, Rachel E. Sipler, Et Al Jan 2016

A Carbon Budget For The Amundsen Sea Polynya, Antarctica: Estimating Net Community Production And Export In A Highly Productive Polar Ecosystem, Pl Yager, Rm Sherrell, Et Al, Rachel E. Sipler, Et Al

VIMS Articles

Polynyas, or recurring areas of seasonally open water surrounded by sea ice, are foci for energy and material transfer between the atmosphere and the polar ocean. They are also climate sensitive, with both sea ice extent and glacial melt influencing their productivity. The Amundsen Sea Polynya (ASP) is the greenest polynya in the Southern Ocean, with summertime chlorophyll a concentrations exceeding 20 μg L−1. During the Amundsen Sea Polynya International Research Expedition (ASPIRE) in austral summer 2010–11, we aimed to determine the fate of this high algal productivity. We collected water column profiles for total dissolved inorganic carbon (DIC) and …


Influence Of Wind Strength And Duration On Relative Hypoxia Reductions By Opposite Wind Directions In An Estuary With An Asymmetric Channel, Ping Wang, Harry V. Wang, Lewis Linker, Kyle Hinson Jan 2016

Influence Of Wind Strength And Duration On Relative Hypoxia Reductions By Opposite Wind Directions In An Estuary With An Asymmetric Channel, Ping Wang, Harry V. Wang, Lewis Linker, Kyle Hinson

VIMS Articles

Computer model experiments are applied to analyze hypoxia reductions for opposing wind directions under various speeds and durations in the north–south oriented, two-layer-circulated Chesapeake estuary. Wind’s role in destratification is the main mechanism in short-term reduction of hypoxia. Hypoxia can also be reduced by wind-enhanced estuarine circulation associated with winds that have down-estuary straining components that promote bottom-returned oxygen-rich seawater intrusion. The up-bay-ward along-channel component of straining by the southerly or easterly wind induces greater destratification than the down-bay-ward straining by the opposite wind direction, i.e., northerly or westerly winds. While under the modulation of the west-skewed asymmetric cross-channel bathymetry …


Modeling Flocculation And Deflocculation Processes Of Cohesive Sediments, Xiaoteng Shen Jan 2016

Modeling Flocculation And Deflocculation Processes Of Cohesive Sediments, Xiaoteng Shen

Dissertations, Theses, and Masters Projects

The transport and fate of cohesive sediments are responsible for many engineering, environmental, economic and policy issues that relate to, for example, siltation and dredging in navigation channels, water quality, water turbidity, pollutant transports, and biological ecosystem responses. Our current understanding, however, is insufficient to conduct accurate quantitative predictions of these processes. This is because the cohesive particles in natural waters will flocculate, which determines the settling, and thus the deposition behaviors. The simulation of flocculation processes is a primary challenge since the time variation of Floc Size Distribution (FSD) is controlled by a partial differential equation that also contains …


On Shelf-Slope Water Mass Exchanges Near Washington Canyon And Norfolk Canyon In The Mid-Atlantic Bight, Haixing Wang Jan 2016

On Shelf-Slope Water Mass Exchanges Near Washington Canyon And Norfolk Canyon In The Mid-Atlantic Bight, Haixing Wang

Dissertations, Theses, and Masters Projects

The physical exchanges between shelf and slope water masses are important drivers of biological productivity in the shelfbreak region of the Mid-Atlantic Bight (MAB). Based on two ocean glider surveys that were conducted in Autumn 2013, and concurrent wind and satellite based sea surface height observations, this study investigates the dynamic mechanisms of wind, surface height variation, water column hydrographic structure, and canyon topography in driving shelf-slope water mass exchanges across the shelfbreak near Norfolk Canyon and Washington Canyon in the MAB. Over the outer shelf, sea surface height variation and wind are important drivers of cross-shelfbreak transport through geostrophic …


Patterns Of Abundance And Community Dynamics In Atlantic Coastal Sharks, Cassidy Peterson Jan 2016

Patterns Of Abundance And Community Dynamics In Atlantic Coastal Sharks, Cassidy Peterson

Dissertations, Theses, and Masters Projects

No abstract provided.