Digital Commons Network^™

Representing Nodes And Arcs In 3d Networks, Glenn Franck, Colin Ware

Center for Coastal and Ocean Mapping

This paper introduces six graphical principles for 30 network displays. These are justified with examples from GraphVisualizer3D, a system developed by the authors to investigate the problems of 30 visualization of information networks. GraphVisualizer3D enables the exploration of sulface color, surface texture, object shape, arc shape and labeling conventions.

Circulation, Fall 1994, Center For Coastal Physical Oceanography, Old Dominion University

CCPO Circulation

Fall 1994 issue of CCPO Circulation featuring article "Modeling Circulation and Larval Transport in the Chesapeake Bay"

Seasonal Composition Of Mesozooplankton In The Pagan River, A Nutrient Enriched Virginia Estuary, Lillian Norman Davis

Biological Sciences Theses & Dissertations

A two year study of the mesozooplankton composition and seasonal distribution was conducted in the Pagan River, a nutrient rich tidal estuary and tributary to the lower James River. The mesozooplankton was dominated by calanoid copepods (80%), with the total zooplankton abundance peaks occurring during spring and fall. The total mean abundance, 3008/m', was somewhat lower than those found by other authors, however the mean abundance at one station approximated those means. Seventy-eight percent of the calanoid copepods were Acartia spp. that were primarily responsible for the fall increase in mesozooplankton abundance. The spring increase was primarily due to increases …

Phosphorus Immobilization In Poultry Litter And Litter-Amended Soils With Aluminum, Calcium And Iron Amendments, D. M. Miller, P. A. Moore Jr., T. C. Daniels

Arkansas Water Resources Center Technical Reports

Arkansas produces approximately one billion broilers each year. Phosphorous (P) runoff from fields receiving poultry litter is believed to be one of the primary factors affecting water quality in Northwest Arkansas. Poultry litter contains approximately 20 g P kg-1, of which about 2 g P kg-1 is water soluble. Soils that have received repeated heavy applications of litter may have water soluble P contents of as high as 10 mg P Kg-1 soil. The objective of this study was to determine if soluble P levels could be reduced in poultry litter and litter-amended soils with Al,Ca, and/or Fe amendments. Poultry …

Temporal Alternation Between Light- And Nutrient-Limitation Of Phytoplankton Production In A Coastal Plain Estuary., Jonathan Pennock, Jonathan H. Sharp

School of Marine Science and Ocean Engineering

ABSTRACT: The potential for Light- and nutrient-limitation of phytoplankton production was examined in the Delaware Estuary, USA, by combining a hierarchy of expenmental approaches including smallscale bioassay experiments, ecosystem-level analysis of nutrient concentration and stoichiometric ratios, and light-limitation modeling. Light was found to be the predominate regulator of phytoplankton growth throughout the estuary during the winter period as a result of high turbidity and a wellmixed water column. However, during late spring, phosphorus (P) was found to limit growth. This observation was confirmed at each of the experimental levels, and was related to several factors, including elevated input ratios (230:l) …

Bulletin 4279 - Streamlining - An Environmentally Sustainable Drainage Network For The Swan Coastal Plain (Peel-Harvey Catchment), Garry Heady, Neil Guise

Bulletins 4000 -

Community Catchment Centre Pinjarra

A network of over 1400 kilometres of drains and modified natural waterways constructed by the Public Works Department criss-crosses the Peel-Harvey catchment. There are also over 3300 kilometres of minor drains and natural waterways in this same region.

The expansion of agriculture relied on this extensive drainage network, which was designed to ensure rapid drainage of the region. Unfortunately there was little regard to future environmental consequences.

Along with drainage water, these same drains now carry high loads of silt and nutrients. Many of the drains are also degraded and require expensive maintenance annually.

Soluble Acidic Species In Air And Snow At Summit, Greenland, Jack E. Dibb, R. Talbot, M H. Bergin

Earth Sciences

Simultaneous measurements of the concentrations of soluble acidic species in the gas, aerosol and snow phases at Summit, Greenland were made during summer 1993. Mean concentrations of gas phase HCOOH, CH₃COOH, and HNO₃ (49±28, 32±17 and 0.9±0.6 nmol m⁻³ STP, respectively) exceeded the concentrations of aerosol-associated HCOO⁻, CH₃COO⁻, and NO₃⁻by 1–3 orders of magnitude. On average, SO₂ concentrations (0.9±0.6 nmol m⁻³ STP) were approximately 1/3 those of aerosol SO₄⁼, but this ratio varied widely due largely to changes in the concentration of …

Ozone Heating And The Destabilization Of Traveling Waves During Summer, Terrence R. Nathan, Eugene Cordero, Long Li

Faculty Publications, Meteorology and Climate Science

The effects of ozone heating on the linear stability of lower stratospheric traveling waves of the summertime, extratropical circulation are examined. Based on coupled equations for the quasigeostrophic potential vorticity and ozone volume mixing ratio, it is shown that the diabatic heating arising from ozone advection can offset the damping due to Newtonian cooling, leading to wave amplification and significant changes in the structure and zonally rectified fluxes of the wave fields in both the lower stratosphere and troposphere. The vertical profile of the zonal mean wind plays a crucial role in determining whether the ozone heating destabilizes eastward and/or …

A Diffuse Reflectance Infrared Fourier Transform Spectroscopic Investigation Of The Oxidation Of Co On Platinum/Tin(Iv) Oxide-Based Catalysts, Julie Christi Stiltner Patrick

Chemistry & Biochemistry Theses & Dissertations

Platinum/tin(IV) oxide-based catalysts have been developed for the oxidation of carbon monoxide at 55 °C and 1 atmosphere pressure. A diffuse reflectance infrared fourier transform spectroscopic (DRIFTS) investigation of this oxidation has been performed. Four catalyst samples have been subjected to a 5% carbon monoxide pretreatment at 125 °C, helium exposure at 55 °C, bottled air (20% oxygen) exposure at 55 °c, and exposure to a 2:1 stoichiometric mixture of carbon monoxide and oxygen at 55 °C. During the course of these exposures, evidence for the development of two different surface carbon monoxide configurations has been found: one that is …

Flow Kinematics And Dynamics Of The Gulf Stream From Composite Imagery, Caitlin Patrice Mullen

OES Theses and Dissertations

A unique set of contemporaneous satellite-tracked drifters and five-day composite satellite images of the North Atlantic is studied in order to infer the near-surface flow kinematics and dynamics of the Gulf Stream. Using fractal and spectral analyses, two kinematic models, and a potential vorticity model, detailed comparisons are made between these data sets.

Fractal and spectral analyses show that the data set is not fractal, there is no geographic variability, and there is not a strong fractal scaling link between the drifter trajectories and composite temperature fronts as had been postulated by several investigators. These results indicate considerably more work …

Circulation, Summer 1994, Center For Coastal Physical Oceanography, Old Dominion University

CCPO Circulation

Summer 1994 issue of CCPO Circulation featuring article "Large Influences From Small Features: Submarine Canyons"

Benthic Community Responses To Hypoxic Conditions In The Lower Rappahannock River, Virginia, Mary Elaine Smith

Biological Sciences Theses & Dissertations

The effects of seasonal low dissolved oxygen conditions upon benthic macroinvertebrate communities were studied in the lower Rappahannock River, a tributary of the Chesapeake Bay. Benthic communities were sampled during March, June, August, and September 1993 at five equidistant depths (5, 10, 15, 20, and 25 m) extending upwards from the deepwater Virginia Benthic Biological Monitoring Station LE3.4 located in the deep basin just inside the mouth of the Rappahannock River. Infaunal species diversity, richness, biomass, and density were measured along with the vertical depth distribution of organisms within the sediment. Significant sediment differences were found between the shallowest, 5 …

Estimation Of Stratospheric Input To The Arctic Troposphere: 7be And 10be In Aerosols At Alert, Canada, Jack E. Dibb, David Meeker, R C. Finkel, J Southon, Marc W. Caffee, Leonard A. Barrie

Earth Sciences

Concentrations of 7Be and 210Pb in 2 years of weekly high-volume aerosol samples collected at Alert, Northwest Territories, Canada, showed pronounced seasonal variations. We observed a broad winter peak in 210Pb concentration and a spring peak in 7Be. These peaks were similar in magnitude and duration to previously reported results for a number of stations in the Arctic Basin. Beryllium 10 concentrations (determined only during the first year of this study) were well correlated with those of 7Be; the atom ratio 10Be/7Be was nearly constant at 2.2 throughout the year. This relatively high value of 10Be/7Be indicates that the stratosphere …

The Prediction Of Sediment And Nutrient Transport In The Buffalo River Watershed Using A Geographic Information System, H. D. Scott, P. A. Smith

Arkansas Water Resources Center Technical Reports

The Buffalo River was established by Congress in 1972 as the first National River in the United States. It is one of the few remaining free-flowing streams in northern Arkansas. The river originates in the higher elevations of the Boston Mountains in Newton County, and generally flows northeastward, intersecting the Springfield and Salem Plateaus as it drops from approximately 2000 feet in the headwaters to around 500 feet at the confluence with the White River in Marion County. It is considered by many to be one of Arkansas' greatest natural treasures, and therefore , there is strong interest in protecting …

Correlating Soil Test Phosphorus Losses In Runoff, D. H. Pote, T. C. Daniel, P. A. Moore Jr., D. J. Nichols, D. R. Edwards, A. N. Sharpley

Arkansas Water Resources Center Technical Reports

Phosphorus in agricultural runoff is often a major cause of accelerated eutrophication of lakes and streams. Previous research has indicated that the amount of dissolved P (DP) in runoff is directly related to P content of the surface soil. Decades of fertilizer application at rates exceeding those of crop uptake have elevated soil test P (STP) levels in areas of intensive crop and livestock production, making this the major source of DP loss in runoff. The objective of our experiment was to relate STP content of Captina silt loam to P concentration and loss in runoff, and determine which STP …

Assessment Of Effectiveness Of Buffer Zones In Removing Impurites In Runoff From Areas Treated With Poultry Litter, I. Chaubey, D. R. Edwards, T. C. Daniels

Arkansas Water Resources Center Technical Reports

Land application of animal manures (e.g. poultry litter, poultry manure, and swine manure) to pasture and range can lead to runoff quality degradation during storms that occur soon after application. Vegetative filter strips (VFS) have been shown to reduce pollution in runoff from row-cropped areas but have not been extensively studied in pasture and range settings. This research involved characterizing performance of fescue VFS in improving quality of runoff from pasture land areas treated with poultry litter and swine manure. The VFS were found to be quite effective in reducing off-site transport of ammonia nitrogen (NH3-N), total Kjeldahl nitrogen (TKN), …

Drought Profile: Haryana State In North India, K. Kailasa Nathan

Drought Network News (1994–2001)

Haryana state is considered the breadbasket of India, along with the Punjab state. The effects of drought (and mitigation of those effects) are therefore of considerable importance for the state. This article considers the state’s drought “profile” through a study of six drought years in Haryana.

Haryana has a semiarid climate in the southwest and a Gangetic plain environment in the rest of the state. About 50% of the state has a moisture deficit. One of the reasons for adverse crop production in the state during June–September is the early withdrawal or late onset of monsoon rains, which contribute nearly …

Droughts Over Homogeneous Regions Of India: 1871–-1990, B. Parathasarathy, A. A. Munot, D. R. Kothawale

Drought Network News (1994–2001)

The summer monsoon (June through September), or southwest seasonal rains, contribute 78% of India’s annual rainfall. It is the greatest climatic water resource of India. The country’s agriculture and food production depend on these rains. Rainfed farming areas in India account for about 70% of the total arable land in the country, with nearly 100 million ha depending on the monsoon rains. The rains also contribute to power generation and industrial production.

Hydrometeorological Considerations For Rainwater Management During Drought Years In Peninsular India, J. B. Singh, B. V. Ramana Rao, J. C. Katyal

Drought Network News (1994–2001)

Peninsular India is located in the tropics; its climate ranges from arid conditions in the rain shadow region (under the influence of Eastern Ghats along the east coast and Western Ghats along the west coast) to humid conditions in regions adjoining the west coast. The average annual rainfall in the region varies from about 500 mm in the interior parts to more than 3000 mm on the crest of Western Ghats. The rainy season commences during the month of June because of the onset of the southwest monsoon near the tip of peninsular India. The southwest monsoon ends during September. …

Drought And Southern Africa: A Note From The Harare Regional Drought Monitoring Centre, Leonard S. Uganai

Drought Network News (1994–2001)

Drought is a normal part of southern Africa’s climate and one of the most important natural disasters in southern Africa. In fact, it is becoming increasingly unusual for drought not to occur somewhere in southern Africa each year. The dependence of most southern African economies on rainfed agriculture emphasizes the importance of drought early warning products for short- and long-term decision making in various sectors of the national economies of the region. Following the 1991–92 drought, which ravaged more than 80% of southern Africa, many in southern Africa now realize the value of meteorological information in weather-sensitive decisions. Requests for …

Drought In Beijing, 1992-93, Zhuang Xie, Dagang Chen

Drought Network News (1994–2001)

Beijing, located in northeast China, has a semiarid monsoon climate, with summer rainfall providing about 70% of the annual precipitation. This climate is conducive to crop growth, although insufficient summer rainfall in 1992–93 caused reductions in crop yields. Normalized departures of monthly precipitation (DR/R%) are shown in Figure 1. Although some months show above-normal precipitation (for example, November 1992, with a rainfall amount [43.3 mm] 7.5 times the normal), rainfall for the 1993 growing period was marked by negative departures from normal. Of the months of the 1993 growing season, only July recorded above-normal rainfall. Precipitation departures in May, September, …

Parameterization Of The Cool Skin Of The Ocean And Of The Air-Ocean Gas Transfer On The Basis Of Modeling Surface Renewal, Alexander Soloviev, Peter Schlüssel

Marine & Environmental Sciences Faculty Articles

Heat and gas transport in molecular sublayers at the air-sea interface is governed by similar laws. A model of renewal type based on the physics of molecular sublayers allows the derivation of a parameterization of the temperature difference across the cool skin of the ocean and of the coefficient of the direct air-sea gas transfer. The surface Richardson number controls the transition from convective instability to wind-induced instability (“rollers” on breaking wavelets) and the Keulegan number controls the transition from the regime of rollers to long-wave breaking. A critical value of the surface Richardson number and of a nondimensional constant …

Decade-Scale Trend In Sea Water Salinity Revealed Through Δ18o Analysis Of Montastraea Annularis Annual Growth Bands, Robert B. Halley, Peter Koenraad Swart, Richard E. Dodge, Harold J. Hudson

Marine & Environmental Sciences Faculty Articles

Stable oxygen isotope ratios (δ¹⁸O) of coral skeletons are influenced by ambient water temperature and by the oxygen isotope ratio in the surrounding sea water, which, in turn, is linked to evaporation (salinity) and precipitation. To investigate this relationship more thoroughly, we collected hourly temperature data from the Hen and Chickens Reef in the Florida Keys between 1975 and 1988 and compared them to the δ¹⁸O of Montastraea annularis skeleton that grew during the same interval. To ensure that we obtained the correct oxygen isotopic range in the skeleton we typically sampled the coral at a …

Application Of A Maximum Likelihood Processor To Acoustic Backscatter For The Estimation Of Seafloor Roughness Parameters, Zoi-Heleni Michalopoulou, Christian De Moustier

Center for Coastal and Ocean Mapping

Maximum likelihood (ML) estimation is used to extract seafloor roughness parameters from records of acoustic backscatter. The method relies on the Helmholtz–Kirchhoff approximation under the assumption of a power‐law roughness spectrum and on the statistical modeling of bottom reverberation. The result is a globally optimum, highly automated technique that is a useful tool in the context of seafloor classification via remote acoustic sensing. The general geometry of the Sea Beam bathymetric system is incorporated into the design of the ML processor in order to make it applicable to real acoustic data collected by this system. The processor is initially tested …

New Sources For The Hot Oxygen Geocorona, P. G. Richards, Michael P. Hickey Ph.D., D. G. Torr

Publications

This paper investigates new sources of thermospheric non thermal (hot) oxygen due to exothermic reactions involving numerous minor (ion and neutral) and metastable species. Numerical calculations are performed for low latitude, daytime, winter conditions, with moderately high solar activity and low magnetic activity. Under these conditions we find that the quenching of metastable species are a significant source of hot oxygen, with kinetic energy production rates a factor of ten higher than those due to previously considered O2+ and NO+ dissociative recombination reactions. Some of the most significant new sources of hot oxygen are reactions involving quenching of O+(²D), O(¹D), …

Coastal Eutrophication Near The Mississippi River Delta, R. Eugene Turner, Nancy Rabalais

Faculty Publications

CHANGES in delivery of river-borne nutrients such as dissolved phosphate, nitrate and silicate, owing to land-use changes and anthropogenic emissions, are known to result in eutrophication1— enhanced phytoplankton blooms—and more severe hypoxic events2–1 in many enclosed bays and seas. Although similar ecological effects might be expected on continental shelves, the occurrence of such eutrophication has remained unresolved5. Here we present evidence of eutrophication of the continental shelf near the outflow of the Mississippi river, obtained by quantifying biologically bound silica (BSi) in diatom remnants within dated sediment cores. BSi accumulation rates are greatest in water depths of 20 to 50 …

On The Low-Frequency Current And Temperature Fluctuations Along The Shelf Break In The South Atlantic Bight, Sunny Yu Wu

OES Theses and Dissertations

Current and temperature data collected along the shelf edge in the South Atlantic Bight were analyzed using a spectral analysis technique. The power spectra of both alongshore currents and temperatures (upon removal of seasonal trends) in the mid- to lower water column suggest a significant energy peak at 28 days. The spatial characteristics of the fluctuations around this period band were determined using the frequency domain empirical orthogonal function (EOF) analysis applied to the concurrent current and temperature records. Consistent results were obtained from the upstream side of the Charleston Bump. Around the 28-day period, temperature seems to have little …

Iodate Transformation By Marine Phytoplankton, Ajcharaporn Udomkit

OES Theses and Dissertations

The speciation and distribution of iodine in the oceans are partly under biological control. Phytoplankton are suspected to mediate the transformation of iodate to iodide via reduction by the enzyme nitrate reductase. However, there has been no direct evidence to support this hypothesis.

The influence of phytoplankton on the speciation of iodine was examined with emphasis on the transformation of iodate to iodide. Six cultures of marine phytoplankton: Skeletonema costatum, Dunaliella tertiolecta, Amphidinium carterae, Tetraselmis levis, Emiliania huxleyi, and Synechococcus sp. , have been examined for their ability to take up and reduce iodate under a reduced nitrate environment. In …

Population Growth In North Carolina: Implications On Coastal Wastewater Management, Carol Anne Kinder

Marine Affairs Theses and Major Papers

The sustainability of North Carolina's coastal resources are threatened from environmental degradation. A decline in water quality has resulted, in part, from a lack of regional consensus on coastal wastewater management. Yet coastal population growth continues without the necessary infrastructure to support domestic wastewater treatment. This paper will attempt to address the feasibility of an ocean outfall in the state of North Carolina by summarizing results of earlier research, drawing expertise from current outfall projects, examining legal and financial obstacles, and evaluating progressive steps toward an integrated planning of coastal wastewater disposal. Integrated Coastal Management (ICM) is one framework through …

Circulation, Spring 1994, Center For Coastal Physical Oceanography, Old Dominion University

CCPO Circulation

Spring 1994 issue of CCPO Circulation featuring article "The MPC Project"