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Full-Text Articles in Life Sciences
Seamless Cross-Scale Modeling With Schism, Yinglong J. Zhang, Fei Ye, Ev Stanev, S Grashorn
Seamless Cross-Scale Modeling With Schism, Yinglong J. Zhang, Fei Ye, Ev Stanev, S Grashorn
VIMS Articles
We present a new 3D unstructured-grid model (SCHISM) which is an upgrade from an existing model (SELFE). The new advection scheme for the momentum equation includes an iterative smoother to reduce excess mass produced by higher-order kriging method, and a new viscosity formulation is shown to work robustly for generic unstructured grids and effectively filter out spurious modes without introducing excessive dissipation. A new higher-order implicit advection scheme for transport (TVD2) is proposed to effectively handle a wide range of Courant numbers as commonly found in typical cross-scale applications. The addition of quadrangular elements into the model, together with a …
Influence Of Reservoir Infill On Coastal Deep Water Hypoxia, Lewis C. Linker, Richard A. Batiuk, Carl F. Cerco, Gary W. Shenk, Richard Tian, Ping Wang, Guido Yactayo
Influence Of Reservoir Infill On Coastal Deep Water Hypoxia, Lewis C. Linker, Richard A. Batiuk, Carl F. Cerco, Gary W. Shenk, Richard Tian, Ping Wang, Guido Yactayo
VIMS Articles
Ecological restoration of the Chesapeake through the Chesapeake Bay total maximum daily load (TMDL) requires the reduction of nitrogen, phosphorus, and sediment loads in the Chesapeake watershed because of the tidal water quality impairments and damage to living resources they cause. Within the Chesapeake watershed, the Conowingo Reservoir has been filling in with sediment for almost a century and is now in a state of near‐full capacity called dynamic equilibrium. The development of the Chesapeake TMDL in 2010 was with the assumption that the Conowingo Reservoir was still effectively trapping sediment and nutrients. This is now known not to …
The Nature Of Organic Carbon In Density-Fractionated Sediments In The Sacramento-San Joaquin River Delta (California), S. G. Wakeham, Elizabeth A. Canuel
The Nature Of Organic Carbon In Density-Fractionated Sediments In The Sacramento-San Joaquin River Delta (California), S. G. Wakeham, Elizabeth A. Canuel
VIMS Articles
Rivers are the primary means by which sediments and carbon are transported from the terrestrial biosphere to the oceans but gaps remain in our understanding of carbon associations from source to sink. Bed sediments from the Sacramento-San Joaquin River Delta (CA) were fractionated according to density and analyzed for sediment mass distribution, elemental (C and N) composition, mineral surface area, and stable carbon and radiocarbon isotope compositions of organic carbon (OC) and fatty acids to evaluate the nature of organic carbon in river sediments. OC was unevenly distributed among density fractions. Mass and OC were in general concentrated in mesodensity …
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
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 …
Optimal Hurricane Overwash Thickness For Maximizing Marsh Resilience To Sea Level Rise, David C. Walters, Matthew L. Kirwan
Optimal Hurricane Overwash Thickness For Maximizing Marsh Resilience To Sea Level Rise, David C. Walters, Matthew L. Kirwan
VIMS Articles
The interplay between storms and sea level rise, and between ecology and sediment transport governs the behavior of rapidly evolving coastal ecosystems such as marshes and barrier islands. Sediment deposition during hurricanes is thought to increase the resilience of salt marshes to sea level rise by increasing soil elevation and vegetation productivity. We use mesocosms to simulate burial of Spartina alterniflora during hurricane-induced overwash events of various thickness (0-60 cm), and find that adventitious root growth within the overwash sediment layer increases total biomass by up to 120%. In contrast to most previous work illustrating a simple positive relationship between …
Using Lidar Elevation Data To Develop A Topobathymetric Digital Elevation Model For Sub-Grid Inundation Modeling At Langley Research Center, Jon Derek Loftis, Harry V. Wang, Rj Deyoung, Wb Ball
Using Lidar Elevation Data To Develop A Topobathymetric Digital Elevation Model For Sub-Grid Inundation Modeling At Langley Research Center, Jon Derek Loftis, Harry V. Wang, Rj Deyoung, Wb Ball
VIMS Articles
Technological progression in light detection and ranging permits the production of highly detailed digital elevation models, which are useful in sub-grid hydrodynamic modeling applications. Sub-grid modeling technology is capable of incorporating these high-resolution lidar-derived elevation measurements into the conventional hydrodynamic modeling framework to resolve detailed topographic features for inclusion in a hydrological transport model for runoff simulations. The horizontal resolution and vertical accuracy of the digital elevation model is augmented via inclusion of these lidar elevation values on a nested 5-m sub-grid within each coarse computational grid cell. This aids in resolving ditches and overland drainage infrastructure at Langley Research …
Levels, Sources And Chemical Fate Of Persistent Organic Pollutants In The Atmosphere And Snow Along The Western Antarctic Peninsula, Ma Khairy, Jl Luek, R Dickhut, R Lohmann
Levels, Sources And Chemical Fate Of Persistent Organic Pollutants In The Atmosphere And Snow Along The Western Antarctic Peninsula, Ma Khairy, Jl Luek, R Dickhut, R Lohmann
VIMS Articles
The Antarctic continent is among the most pristine regions; yet various organic contaminants have been measured there routinely. Air and snow samples were collected during the austral spring (October November, 2010) along the western Antarctic Peninsula and analyzed for organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) to assess the relative importance of long-range transport versus local primary or secondary emissions. Highest concentrations of PCBs, PBDEs and DDTs were observed in the glacier's snow sample, highlighting the importance of melting glaciers as a possible secondary source of legacy pollutants to the Antarctic. In the atmosphere, contaminants were …
Water Residence Time In Chesapeake Bay For 1980-2012, Jb Du, Jian Shen
Water Residence Time In Chesapeake Bay For 1980-2012, Jb Du, Jian Shen
VIMS Articles
Concerns have grown over the increase of nutrients and pollutants discharged into the estuaries and coastal seas. The retention and export of these materials inside a system depends on the residence time (RT). A long-term simulation of time-varying RT of the Chesapeake Bay was conducted over the period from 1980 to 2012. The 33-year simulation results show that the mean RT of the entire Chesapeake Bay system ranges from 110 to 264 days, with an average value of 180 days. The RT was larger in the bottom layers than in the surface layers due to the persistent stratification and estuarine …
Complex Coastal Change In Response To Autogenic Basin Infilling: An Example From A Sub-Tropical Holocene Strandplain, Christopher J. Hein, Dm Fitzgerald, Lhp De Souza, Iy Georgiou, Iv Buynevich, Et Al.
Complex Coastal Change In Response To Autogenic Basin Infilling: An Example From A Sub-Tropical Holocene Strandplain, Christopher J. Hein, Dm Fitzgerald, Lhp De Souza, Iy Georgiou, Iv Buynevich, Et Al.
VIMS Articles
Thick bay-fill sequences that often culminate in strandplain development serve as important sedimentary archives of land-ocean interaction, although distinguishing between internal and external forcings is an ongoing challenge. This study employs sediment cores, ground-penetrating radar surveys, radiocarbon dates, palaeogeographic reconstructions and hydrodynamic modelling to explore the role of autogenic processes - notably a reduction in wave energy in response to coastal embayment infilling - in coastal evolution and shoreline morphodynamics. Following a regional 2 to 4m highstand at ca 58ka, the 75km(2) Tijucas Strandplain in southern Brazil built from fluvial sediments deposited into a semi-enclosed bay. Holocene regressive deposits are …
Unstructured-Grid Model For The North Sea And Baltic Sea: Validation Against Observations, Yinglong J. Zhang, Ev Stanev, S Grashorn
Unstructured-Grid Model For The North Sea And Baltic Sea: Validation Against Observations, Yinglong J. Zhang, Ev Stanev, S Grashorn
VIMS Articles
A new unstructured grid model and its application to the North Sea and Baltic Sea are described. The research focus is on the dynamics in the two basins and in the multiple straits connecting them and more specifically on how the model replicates the temporal and spatial variability of physical processes. The comparison against observed data indicates the realism in the simulations of the exchange flows. The simulations demonstrated that in contrast to the tidal variability which decreases in the strait, the role of the barotropic forcing due to weather systems increases. In this zone reversal of transport is well …