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Articles 2641 - 2670 of 3337

Full-Text Articles in Earth Sciences

Proceedings Of The Arkansas Water Resources Center Annual Conference: Environmental Hydrology, Kenneth F. Steele Nov 2000

Proceedings Of The Arkansas Water Resources Center Annual Conference: Environmental Hydrology, Kenneth F. Steele

Arkansas Water Resources Center Technical Reports

The papers and abstracts in these proceedings are the result of a joint conference of the Arkansas Water Resources Center (A WRC) with the SouthCentral Section of the Geological Society of America. The joint conference was a success with about 250 participants. A WRC sponsored two sessions on Environmental Hydrology and a short course titled "Hydrogeology and Geochemistry of Salt Water Contamination." The Environmental Hydrology presentations covered wide-ranging topics that reflect the diversity of the environmental settings across Arkansas. Topics ranged from salt water and critical ground water issues in the Delta to endangered species and interbasin ground-water recharge in …


Modifications Of The C37 Alkenone And Alkenoate Composition In The Water Column And Sediment: Possible Implications For Sea Surface Temperature Estimates In Paleoceanography, Joan O. Grimalt, Jürgen Rullkötter, Marie-Alexandrine Sicre, Roger Summons, John Farrington, H. Rodger Harvey, Miguel Goñi, Ken Sawada Nov 2000

Modifications Of The C37 Alkenone And Alkenoate Composition In The Water Column And Sediment: Possible Implications For Sea Surface Temperature Estimates In Paleoceanography, Joan O. Grimalt, Jürgen Rullkötter, Marie-Alexandrine Sicre, Roger Summons, John Farrington, H. Rodger Harvey, Miguel Goñi, Ken Sawada

OES Faculty Publications

The literature pertaining to C37 alkenone and C37 and C38 alkenoate production and diagenesis has been reviewed and evaluated for issues that might jeopardize their usefulness in paleotemperature estimation. We also examined the use of the C37 alkenones as paleoproductivity indicators, the stability of their δ13C isotopic compositions, and their incorporation into the nonsolvent extractable organic matter fraction. Biological transformation of organic matter by bacteria and zooplankton does not appear to cause significant changes to the ratio of C37:2 and C37:3 alkenones, but there are major alterations in the relative composition of alkenoates. Studies of water column processes and postdepositional …


Investigation Of Optimum Sample Number And Timing For Determining Pollution Loads, T. S. Soerens, Marc A. Nelson Oct 2000

Investigation Of Optimum Sample Number And Timing For Determining Pollution Loads, T. S. Soerens, Marc A. Nelson

Arkansas Water Resources Center Technical Reports

In order to determine the impacts of non point source (NPS) pollution and to develop Total Maximum Daily Loads (Tr\tfDLs), accurate measurements of pollution loads in streams are critical. The objectives of this study were to accurately detemline pollutant loads at two sites by intensive storm sampling, to develop sub-sampling and other data analysis techniques, to detemline the effect of sample interval on load calculation accuracy, and to find the minimum sample interval required to determine storm loads at a required accuracy. The two stream sites used were a 1st order and a 3rd order stream in the Illinois River …


Response Of A First-Order Stream In Maine To Short-Term In-Stream Acidification, S. A. Norton, R. Wagai, T. Navratil, J. M. Kaste, F. A. Rissberger Sep 2000

Response Of A First-Order Stream In Maine To Short-Term In-Stream Acidification, S. A. Norton, R. Wagai, T. Navratil, J. M. Kaste, F. A. Rissberger

Dartmouth Scholarship

An experimental short-term acidification with HCl at a first-order stream in central Maine, USA was used to study processes controlling the changes in stream chemistry and to assess the ability of stream substrate to buffer pH. The streambed exerted a strong buffering capacity against pH change by ion exchange during the 6-hour acidification. Streambed substrates had substantial cation and anion exchange capacity in the pH range of 4.1 to 6.5. The ion exchange for cations and SO42- were rapid and reversible. The speed of release of cations from stream substrates was Na1+> Ca2+ > Mg2+ > Al …


Ground Water In Northwest Arkansas: Minimizing Nutrient Contamination From Non-Point Sources In Karst Terrane, R. K. Davis, J. V. Brahana, J. S. Johnston Sep 2000

Ground Water In Northwest Arkansas: Minimizing Nutrient Contamination From Non-Point Sources In Karst Terrane, R. K. Davis, J. V. Brahana, J. S. Johnston

Arkansas Water Resources Center Technical Reports

The purpose of the project is to evaluate the effectiveness of Best Management Practices (BPMs) in preventing non-point source contamination of the ground-water resources in the karst terrane of northwestern Arkansas. Limestone and dolomite aquifers in the region are highly vulnerable to contamination. Ground-water studies performed in the region during the last two decades indicate degradation of these carbonate aquifers by nutrients and bacteria. The expeditious growth of the poultry industry during this period, in combination with the inordinate population growth of the region constitute a threat to the ground-water resources from both point sources and non-point sources of contamination. …


Economics Of Using On-Farm Reservoirs To Distribute Diverted Surface Water To Depleted Ground Water Areas Of The Southern Mississippi Valley Region, Eric J. Wailes, Kenneth B. Young, James Smartt, Gail L. Cramer Aug 2000

Economics Of Using On-Farm Reservoirs To Distribute Diverted Surface Water To Depleted Ground Water Areas Of The Southern Mississippi Valley Region, Eric J. Wailes, Kenneth B. Young, James Smartt, Gail L. Cramer

Arkansas Water Resources Center Technical Reports

Rapid ground water depletion has become a significant problem for parts of the Southern Mississippi River Valley. In 1997, the Arkansas Soil and Water Conservation Commission (ASWCC) declared six counties in the Grand Prairie of Arkansas critical ground water areas. A proposed solution to the ground water depletion problem in this region is to divert surplus flows from the White River by a canal system to the farmer stakeholders. To make the system work, on-farm reservoirs will be needed to store and manage the diverted surface water for crop irrigation use during the growing season.


Theoretical Basis For The Ce-Qual-W2 River Basin Model, Scott A. Wells, Thomas M. Cole Aug 2000

Theoretical Basis For The Ce-Qual-W2 River Basin Model, Scott A. Wells, Thomas M. Cole

Civil and Environmental Engineering Faculty Publications and Presentations

The primary objective of this research is to integrate a riverine model into the existing W2 code that would provide the capability for modeling entire watersheds. This task was accomplished by the following steps:

• Formal derivation of governing equations and solution algorithm with general channel slope

• Detailed analysis of algorithm for linking branches and smooth implementation of boundary conditions between branches

• Algorithm development and changes to basic model code (including branch definitions with slope, slope correction to solution algorithm, transfer of momentum between internal branches)

These tasks were performed with the following constraints and initiatives:

• Utilize …


Alteration Processes Of Alkenones And Related Lipids In Water Columns And Sediments, H. Rodger Harvey Aug 2000

Alteration Processes Of Alkenones And Related Lipids In Water Columns And Sediments, H. Rodger Harvey

OES Faculty Publications

Alkenones produced by the haptophyte algae are currently being used as indices of sea surface temperature in recent and past ocean environments, but limited information is available concerning the impact of biotic and abiotic processes on the integrity of these long chain lipids. This synthesis provides selected background information on major alteration processes that must be considered before such indices can be used with confidence. A number of processes in the water column and surface sediments have the potential to impact the structural integrity of alkenones and compromise their ability as temperature markers. Processes discussed include the alteration of alkenone …


Bulletin 4418 - Nebru Focus Catchment Report, Agriculture Western Australia Jul 2000

Bulletin 4418 - Nebru Focus Catchment Report, Agriculture Western Australia

Bulletins 4000 -

Nehru Focus Catchment is located in the upper reaches of the Arrowsmith Catchment. It is roughly bounded by Sunset Road in the north, the north-south Kadathinni Hills to the east, the Three Springs - Eneabba Road to the south and Reed Road in the west. It changes in elevation from 372 metres Australian Height Datum (AHD) at roughly the intersection of Nehru Rd the Kadathinni Hills to the east and 220 metres AHD near the outlet of the catchment into the Arrowsmith River.

The total area of the catchment is just over 7,400 hectares.

One of the prime areas of …


Environmental Impacts Of New Solutions: Two Case Studies, Lori Potter, Michael Freeman Jun 2000

Environmental Impacts Of New Solutions: Two Case Studies, Lori Potter, Michael Freeman

Water and Growth in the West (Summer Conference, June 7-9)

32 pages.

Contains footnotes and references.


Groundwater And Growth Management In The New West: Evolving Law And Practice, A. Dan Tarlock Jun 2000

Groundwater And Growth Management In The New West: Evolving Law And Practice, A. Dan Tarlock

Water and Growth in the West (Summer Conference, June 7-9)

13 pages.


The Water Development-Growth Relationship: Case Studies, Edward F. Harvey Jun 2000

The Water Development-Growth Relationship: Case Studies, Edward F. Harvey

Water and Growth in the West (Summer Conference, June 7-9)

7 pages.


Climate Variability And Western Water: What Can We Expect?, Roger S. Pulwarty Jun 2000

Climate Variability And Western Water: What Can We Expect?, Roger S. Pulwarty

Water and Growth in the West (Summer Conference, June 7-9)

7 pages.


Agenda: Water And Growth In The West, University Of Colorado Boulder. Natural Resources Law Center, The William And Flora Hewlett Foundation Jun 2000

Agenda: Water And Growth In The West, University Of Colorado Boulder. Natural Resources Law Center, The William And Flora Hewlett Foundation

Water and Growth in the West (Summer Conference, June 7-9)

1 v. (various pagings) : ill., maps ; 29 cm. + 1 CD-ROM (4 3/4 in.) + supplement (207 p. ; 29 x 24 cm.)

"Conference co-sponsor The William and Flora Hewlett Foundation."

Conference moderators included University of Colorado School of Law professors Gary C. Bryner, James N. Corbridge, Jr., David H. Getches, Douglas S. Kenney, Kathryn M. Mutz, Peter D. Nichols and Charles F. Wilkinson.

Accompanied by: CD-ROM (4 3/4 in.) and supplement (xiv, 140, [49] p.)

Includes bibliographical references

The event will cover a breadth of issues, including demographics and water-use trends, improved planning and efficient use, implementation …


A Conceptual Hydrogeological Model For The Lake Warden Recovery Catchments Esperance, Western Australia, R Short May 2000

A Conceptual Hydrogeological Model For The Lake Warden Recovery Catchments Esperance, Western Australia, R Short

Resource management technical reports

The National Land and Water Resource Audit (NLWRA), has identified Dryland Salinity as one of seven major themes for an audit of the nation’s land, water, vegetation and natural resource management. Within this theme, Project 3 has been developed to investigate a key catchment type and how management scenarios will impact on dryland salinity processes. The Lake Warden catchments have been chosen as one of four catchment water balance studies to be undertaken nationally. The catchment water balance analysis will be undertaken using numerical modelling by the CSIRO, Division of Land and Water.


The Rural Towns Program : Groundwater Modelling : The Merredin Catchment, J Matta May 2000

The Rural Towns Program : Groundwater Modelling : The Merredin Catchment, J Matta

Resource management technical reports

Agriculture Western Australia (Agwest), as part of the Rural Towns Program, was engaged to test the application of a groundwater model for potential future management options against salinity for the Merredin townsite. This report illustrates some of the options that could be implemented to achieve the objective of salinity management.


Expression Of A Dominant-Negative Mutant Of P21ras Inhibits Induction Of Nitric Oxide Synthase And Activation Of Nuclear Factor-Kb In Primary Astrocytes, Kalipada Pahan, Xiaojuan Lu, Michael J. Mckinney, Charles Wood, Faruk G. Sheikh, John R. Raymond Jan 2000

Expression Of A Dominant-Negative Mutant Of P21ras Inhibits Induction Of Nitric Oxide Synthase And Activation Of Nuclear Factor-Kb In Primary Astrocytes, Kalipada Pahan, Xiaojuan Lu, Michael J. Mckinney, Charles Wood, Faruk G. Sheikh, John R. Raymond

School of Biological Sciences: Faculty Publications

The present study underlines the importance of p21ras in regulating the inducible nitric oxide synthase (iNOS) in primary astrocytes. Bacterial lipopolysaccharides induced the GTP loading of p21ras, and the expression of a dominant-negative mutant of p21ras (Dp21ras) inhibited lipopolysaccharide-induced GTP loading in rat primary astrocytes. To delineate the role of p21ras in the induction of iNOS, we examined the effect of Dp21ras on the expression of iNOS and the production of nitric oxide. It is interesting that expression of Dp21ras markedly inhibited the production of nitric oxide and the expression of iNOS in lipopolysaccharide- and pro-inflammatory cytokine (tumor necrosis factor-a, …


Oxygen Isotopes And Metolachlor Residues In Water Samples From A Portion Of The Canajoharie Creek Watershed, Central New York, John M. Nadeau Jan 2000

Oxygen Isotopes And Metolachlor Residues In Water Samples From A Portion Of The Canajoharie Creek Watershed, Central New York, John M. Nadeau

Geology Theses and Dissertations

Increased ground and surface water contamination has fueled the need for a better understanding of factors affecting hydrogeological settings. Seasonal variability in the recharge of an aquifer can affect the rate and amount of contamination that can occur. Stable isotopes have been previously investigated as tracers to determine flow paths of the water and contaminants. In this study, oxygen isotopes were used to determine the factors that influence seasonal variations in ground and surface water, such as well location, aquifer type, surface water sites, and soil type. Samples were collected from different locations around the Canajoharie Field Site, including wells …


Variation Of Constitutive Model Formulation On Analytical Cake Filtration Models, Scott A. Wells Jan 2000

Variation Of Constitutive Model Formulation On Analytical Cake Filtration Models, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

Constitutive properties are required to model porosity, effective stress, porewater pressure, or permeability during cake filtration. By using an analytical cake filtration model based on Tiller (1975) with various constitutive property formulations, predictions of effective stress, permeability, and porosity distributions in a filter cake can be made. This analytical approach was only valid when spatially average values of porosity and pressure differential were constant over time. Several different constitutive property formulations were compared to data of effective stress and permeability as a function of porosity for kaolin clay in water. Also the spatial distribution of porosity in a filter cake …


Natural And Anthropogenic Influences On The Distribution Of The Threatened Neosho Madtom In A Midwestern Warmwater Stream, Mark L. Wildhaber, Vernon M. Tabor, Daniel W. Mulhern, Kenneth L. Powell, Scott P. Sowa Jan 2000

Natural And Anthropogenic Influences On The Distribution Of The Threatened Neosho Madtom In A Midwestern Warmwater Stream, Mark L. Wildhaber, Vernon M. Tabor, Daniel W. Mulhern, Kenneth L. Powell, Scott P. Sowa

United States Geological Survey: Staff Publications

We attempted to discern the contributions of physical habitat, water chemistry, nutrients, and contaminants from historic lead-zinc mining activities on the riffle-dwelling benthic fish community of the Spring River, a mid western warm water stream that originates in Missouri and flows into Kansas and Oklahoma. The Spring River has a fish community that includes the Neosho madtom Noturus placidus, a species federally listed as threatened. Although anthropogenic factors such as contaminants limited populations and densities of fishes, an integrated assessment of natural and anthropogenic factors was necessary to effectively estimate the influence of the latter. Fish populations in the …


Modeling The Bull Run River-Reservoir System, Scott A. Wells Jan 2000

Modeling The Bull Run River-Reservoir System, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

The City of Portland, Water Bureau currently operates 2 Bull Run reservoirs, Reservoir #2 and Reservoir #1 as a water supply source in the Bull Run watershed shown in Figure 1 and Figure 2. The Water Bureau wants to operate their water supply system in order to meet both water supply objectives and fish habitat objectives downstream of the Bull Run reservoirs in Bull Run River. In addition, a third Bull Run reservoir has been proposed as an additional water supply source. This reservoir also may be used to meet water supply and fish habitat objectives in Bull Run River. …


Iron And Manganese In The Ross Sea, Antarctica: Seasonal Iron Limitation In Antarctic Shelf Waters, Peter N. Sedwick, Giacomo R. Ditullio, Denis J. Mackey Jan 2000

Iron And Manganese In The Ross Sea, Antarctica: Seasonal Iron Limitation In Antarctic Shelf Waters, Peter N. Sedwick, Giacomo R. Ditullio, Denis J. Mackey

OES Faculty Publications

Dissolved iron and manganese and total dissolvable iron were measured in water column samples from the Polynya Region of the southern Ross Sea in cruises in Nov.-Dec. 1994 (spring 1994) and Dec. 1995 to Jan. 1996 (summer 1995). Iron and manganese addition bottle incubation experiments were also performed on these cruises to assess the nutritional sufficiency of ambient iron and manganese concentrations for phytoplankton growth. Generally high dissolved iron concentrations (>0.5 nM) and relatively complex iron and manganese vertical profiles were obtained in spring 1994 vs. summer 1995. Dissolved iron concentrations in the upper water column averaged 1.0 nM …


Dating Marine Terraces With Relative-Age And Correlated-Age Methods, Daniel R. Muhs Jan 2000

Dating Marine Terraces With Relative-Age And Correlated-Age Methods, Daniel R. Muhs

United States Geological Survey: Staff Publications

Coastal landforms, and particularly emergent marine terraces, a re amongt he most importantg eomorphicfe aturesi n studieso f Quaternarys eal evel fluctuationsa nd neotectonics. A general model, first articulated by Alexander (1953) and borne out by detailedr ecent studieso n many coastlinesi,s that emergent flights of erosional terraces and coral reefs (Fig. 1) are the resulto f glacioeustaticallyc ontrolledf luctuations of global sea level superimposed on steady uplift. Similiarity of U-series ages of coral from both constructional reefsi n the tropicsa nd erosionalt erracesi n midlatitudesh as provided a rigorous test of this model (Mesolella and others, 1969; Bloom and …


Geomorphometry – Diversity In Quantitative Surface Analysis, Richard J. Pike Jan 2000

Geomorphometry – Diversity In Quantitative Surface Analysis, Richard J. Pike

United States Geological Survey: Staff Publications

A widening variety of applications is diversifying geomorphometry (digital terrain modelling), the quantitative study of topography. An amalgam of earth science, mathematics, engineering and computer science, the discipline has been revolutionized by the computer manipulation of gridded terrain heights, or digital elevation models (DEMs). Its rapid expansion continues. This article reviews the remarkable diversity of recent morphometric work in 15 selected topics and discusses their significance and prospects. The quantitative analysis of industrial microsurface topography is introduced to the earth science community. The 14 other topics are Internet access to geomorphometry; global DEMs; DEM modelling of channel networks; …


Single-Dilution Enzyme-Linked Immunosorbent Assay For Quantification Of Antigen-Specific Salmonid Antibody, Stewart W. Alcorn, Ronald J. Pascho Jan 2000

Single-Dilution Enzyme-Linked Immunosorbent Assay For Quantification Of Antigen-Specific Salmonid Antibody, Stewart W. Alcorn, Ronald J. Pascho

United States Geological Survey: Staff Publications

An enzyme-linked immunosorbent assay (ELISA) was developed on the basis of testing a single dilution of serum to quantify the level of antibody to the p57 protein of Renibacterium salmoninarum in sockeye salmon (Oncorhynchus nerka). The levels of antibody were interpolated from a standard curve constructed by relating the optical densities (OD) produced by several dilutions of a high-titer rainbow trout (O. mykiss) antiserum to the p57 protein. The ELISA OD values produced by as many as 36 test sera on each microplate were compared with the standard curve to calculate the antigen-specific antibody activity. Repeated …


Viability Of Piping Plover Charadrius Melodus Metapopulations, Jonathan H. Plissner, Susan M. Haig Jan 2000

Viability Of Piping Plover Charadrius Melodus Metapopulations, Jonathan H. Plissner, Susan M. Haig

United States Geological Survey: Staff Publications

The meta-population viability analysis package, vortex, was used to examine viability and recovery objectives for piping plovers Charadrius melodus, an endangered shorebird that breeds in three distinct regions of North America. Baseline models indicate that while Atlantic Coast populations, under current management practices, are at little risk of near-term extinction, Great Plains and Great Lakes populations require 36% higher mean fecundity for a significant probability of persisting for the next 100 years. Meta-population structure (i.e. the delineation of populations within the meta-population) and inter-population dispersal rates had varying effects on model results; however, spatially-structured meta-populations exhibited lower viability than …


Aquatic Dissipation Of The Herbicide Triclopyr In Lake Minnetonka, Minnesota, Kurt D. Getsinger, David G. Petty, John D. Madsen, John G. Skogerboe, Bruce A. Houtman, William T. Haller, Alison M. Fox Jan 2000

Aquatic Dissipation Of The Herbicide Triclopyr In Lake Minnetonka, Minnesota, Kurt D. Getsinger, David G. Petty, John D. Madsen, John G. Skogerboe, Bruce A. Houtman, William T. Haller, Alison M. Fox

United States Army Corps of Engineers, Omaha District

A study of the aquatic fate of the triethylamine salt of triclopyr (3,5,6-trichloro-2- pyridinyloxyacetic acid) was conducted in three bays of Lake Minnetonka, Minnesota. Triclopyr is under review by the US Environmental Protection Agency as a selective aquatic herbicide. The primary purpose of this study was to determine dissipation rates of the parent active ingredient, triclopyr, and its major metabolites, 3,5,6-trichloropyridinol (TCP) and 3,5,6-trichloro-2-methoxypyridine (TMP) in selected matrices including water, sediment, plants, finfish and shellfish. Two 6.5- ha plots dominated by the weedy species Eurasian watermilfoil (Myriophyllum spicatum L) were treated with triclopyr-triethylammonum at a rate of 2.5mg AE liter …


Bulletin 4446 - Ord Land And Water Management Plan 2000, Agriculture Western Australia, Community Of Kununurra Jan 2000

Bulletin 4446 - Ord Land And Water Management Plan 2000, Agriculture Western Australia, Community Of Kununurra

Bulletins 4000 -

The wise use of the land and water of the Ord has become an imperative driven by increasing awareness of the impacts of current uses on ground water and the on the quality of the Ord River itself.

We have been lucky as a community that these resources are still in reasonable order and that we have the time to address the resource management challenges associated with our use of them. There is a wide range of land and water management issues to be addressed and all those involved have responsibilities to address some of those issues.


Dalyup Catchment 2000, Esperance Catchment Support Team Jan 2000

Dalyup Catchment 2000, Esperance Catchment Support Team

Natural resources published reports

This 'State of the Dalyup Catchment' document is a snapshot of the condition of the Catchment in the year 2000. It records the current level of knowledge of the natural resources in the Catchment and discusses some of the management issues and options. This document is a benchmark and through ongoing monitoring, trends in the condition of the Catchment can be identified.

Its primary purpose is as a tool for resource planning such as a surface water management plan, river action plan or revegetation plan. It can also be used in the preparation of funding applications.


Tidally Induced Flow In Chwaka Bay Zanzibar, O U. Mwaipopo Dec 1999

Tidally Induced Flow In Chwaka Bay Zanzibar, O U. Mwaipopo

Tanzania Journal of Science

Time series data of currents and sea current levels recorded by current meter and tide gauges, respectively from Chwaka Bay, Zanzibar were obtained from the entrance near to Mapopwe Creek and at the middle of the bay. The analysis of the data reveals that the tidal currents had an asymmetry near the entrance to Mapopwe Creek where the ebb currents were stronger than flood currents although the ebb periods were considerably longer than flood periods.