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Articles 16621 - 16650 of 17789
Full-Text Articles in Entire DC Network
Soil Management For Sustainable Agriculture : Background Papers From A Workshop Organized By The Research Review Committee Of The Grains Section Of The Western Australian Farmers Federation Held At Perth Civic Centre, September 29-30, 1987, Western Australian Farmers' Federation, G A. Robertson
Soil Management For Sustainable Agriculture : Background Papers From A Workshop Organized By The Research Review Committee Of The Grains Section Of The Western Australian Farmers Federation Held At Perth Civic Centre, September 29-30, 1987, Western Australian Farmers' Federation, G A. Robertson
Resource management technical reports
No abstract provided.
Surface Sediments And Their Relationship To Water Quality In Hillsborough Bay, A Highly Impacted Subdivision Of Tampa Bay, Florida, J.O.R. Johansson, A.P. Squires
Surface Sediments And Their Relationship To Water Quality In Hillsborough Bay, A Highly Impacted Subdivision Of Tampa Bay, Florida, J.O.R. Johansson, A.P. Squires
Reports
This paper will summarize the composition of surface sediment and sediment oxygen demand rated in Hillsborough Bay. Also, a first attempt is made to relate the nutrients released from these sediments to the phytoplankton, the dominant primary producers of the bay.
Geochemical Evidence For Suppression Of Pelagic Marine Productivity At The Cretaceous/Tertiary Boundary, James C. Zachos, Michael A. Arthur, Walter E. Dean
Geochemical Evidence For Suppression Of Pelagic Marine Productivity At The Cretaceous/Tertiary Boundary, James C. Zachos, Michael A. Arthur, Walter E. Dean
United States Geological Survey: Staff Publications
The normal, biologically productive ocean is characterized by a gradient of the 13C /12C ratio from surface to deep waters. Here we present stable isotope data from planktonic and benthic microfossils across the Cretaceous/Tertiary boundary in the North pacific, which reveal a rapid and complete breakdown in this biologically mediated gradient. The fluxes of barium (a proxy for organic carbon) and CaCO, also decrease significantly at the time of the major marine plankton extinctions. The implied substantial reduction in oceanic primary productivity persisted for ~0.5 Myr before the carbon isotope gradient was gradually re-established. In addition, the …
Foraminiferida Of The Madison Group (Mississippian) Of The Williston Basin, North Dakota, Kurt E. Eylands
Foraminiferida Of The Madison Group (Mississippian) Of The Williston Basin, North Dakota, Kurt E. Eylands
Theses and Dissertations
More than 1500 thin-sections from 73 wells in the North Dakota part of the Williston Basin were searched for their foraminiferal content. This thin-section survey of the Bottineau, Tilston, Frobisher-Alida, and Ratcliffe intervals yielded more than 700 identifiable foraminifers assigned to 26 species.
Most of the Madison foraminifers of the Williston Basin can be placed in one of two superfamilies, the Tournayellacia and the Endothyracea. The Bottineau and Tilston intervals yielded more specimens from the superfamily Tournayellacea while the Frobisher-Alida and Ratcliffe intervals yielded more specimens from the superfamily Endothyracea.
The foraminifers occurred in irregular stratigraphic zones The Bottineau and …
Lake Mixing Dynamics And Water Quality Models, Heinz G. Stefan
Lake Mixing Dynamics And Water Quality Models, Heinz G. Stefan
Journal of the Minnesota Academy of Science
ABSTRACT-To forecast water quality changes or to evaluate the potential success of restoration measures in lakes, it is necessary to formulate "models" which relate lake water quality to the inflows and outflows of materials and energy. Concepts of dynamic deterministic (cause-effect) models and examples are presented. The relationship between internal thermo-hydraulic processes and water quality is stressed. Stratification mixing, and nutrient kinetics are included in these models.
Residence Times Of Minnesota Groundwaters, Scott C. Alexander, E. Calvin Alexander Jr.
Residence Times Of Minnesota Groundwaters, Scott C. Alexander, E. Calvin Alexander Jr.
Journal of the Minnesota Academy of Science
ABSTRACT-Tritium, 14C, and nitrate analyses for eighty groundwater samples from selected Minnesota aquifers indicate a range of residence times from a few days or weeks to tens of thousands of years. The presence of significant nitrate contamination in groundwater is confined to recent or mixed groundwaters. Isotopic studies can yield information that will be useful in the design of effective groundwater protection plans in Minnesota.
Human Impacts To Minnesota Wetlands, Carol A. Johnston
Human Impacts To Minnesota Wetlands, Carol A. Johnston
Journal of the Minnesota Academy of Science
ABSTRACT-Minnesota's 3.6 million ha of wetlands have been impacted by a variety of human activities, including agricultural drainage, urbanization, water control, and nonpoint source pollution. More than half of Minnesota's wetlands have been destroyed since the first European settlers arrived, an average loss of about 35,600 ha/yr. Drainage for agriculture is the major cause of wetland loss in Minnesota, particularly in southern Minnesota and the Red River Valley. In addition to impacting wetlands directly, wetland drainage affects downstream areas by increasing flood flows, and releasing sediment and nutrients. Urban development and highway construction affect a smaller proportion of Minnesota's wetlands, …
The Comprehensive County Water Planning Process In South Central Minnesota, Henry W. Quade, Robert A. Barrett
The Comprehensive County Water Planning Process In South Central Minnesota, Henry W. Quade, Robert A. Barrett
Journal of the Minnesota Academy of Science
ABS~CT-Development of co_unt)_' comprehensi~e water plans is underway in a majority of Minnesota counties as a result of recent leg1slat1on. The planning process requires the fashioning of new relationships and r~les for local and st~te _government, agen':Y personnel, and interdisciplinary technical teams. Early water planning efforts reve~I. s1gmfi~ant problerI:s with the adequacy and applicability of existing water resources da~. Assessment of e1t1Zen attitudes regarding water resource issues was found necessary to link support with policy and develop public education activities. Analysis of water resources data combined with citizen and stat~ agency attitudes has enabled counties in south central Minnesota to …
The Effect On Farm Profit Of Conserving Stubble To Prevent Wind Erosion, A D. Bathgate
The Effect On Farm Profit Of Conserving Stubble To Prevent Wind Erosion, A D. Bathgate
Journal of the Department of Agriculture, Western Australia, Series 4
Over-grazing of stubbles is a major cause of winf erosion on WesternAustralian farms. Stubble contributes to the 'roughness' of the paddock; as the roughness is reduced, the risk of winf erosion is increased.
The risk of lupinosis in sheep has previously reduced the likelihood of lupin stubble being over grazed, but the development of Gungurru, a phomopsis-resistent variety of lupin, has increased the potential for over-grazing and hence the probability of wind erosion.
This article describes the economic benefit (or cost) of conserving stubble at the conservation standards.
Paleoenvironmental History Of The Middle Ordovician Rugosa Of Eastern North America, Gretchen Hampt Andreasen
Paleoenvironmental History Of The Middle Ordovician Rugosa Of Eastern North America, Gretchen Hampt Andreasen
Honors Papers
Our understanding of the structure and function of biological systems can be increased when viewed in the context of their evolutionary history on a geological time scale. Generally, both paleoecology and ecology have focused on the interrelationships of organisms and their environments in short time frames. For instance, a paleoecologist might study the fossil communities of the Columbus Limestone reefal environment at Marblehead, Ohio, or an ecologist might attempt to characterize the interrelationship of glacier lilies and their pollinators. Both workers may realize that the organisms they study evolved in response to ecological pressures, yet neither, most likely, considers that …
Sedimentary Depositional Cyclicity, Mission Canyon And Charles Formations (Mississippian), Williston Basin, North Dakota, Jean L. Hoff
Sedimentary Depositional Cyclicity, Mission Canyon And Charles Formations (Mississippian), Williston Basin, North Dakota, Jean L. Hoff
Theses and Dissertations
Workers within the Williston Basin have repeatedly reported the presence of sedimentary cyclicity within the carbonate and evaporite succession of the Mississippian Madison Group. Descriptions of cyclicity are diverse and commonly conflict. Previous work has been exclusively qualitative. This study used a group of statistical techniques in a method designed specifically for the objective identification and evaluation of cyclicity in the lithofacies sequence of the Mission Canyon and lower Charles Formations in North Dakota.
Twelve cores were sampled at every visually distinguishable lithologic unit. Forty-six lithologic components were counted in each sample on a presence-absence basis. The phi association coefficient …
Cultivar Evaluation On Low Rainfall Heavy Textured Soils., Bradley Nutt
Cultivar Evaluation On Low Rainfall Heavy Textured Soils., Bradley Nutt
Experimental Summaries - Plant Research
a. Trial 88GE34
Cultivar evaluation in machine sown plots.
Location: NMRS
The higher seed yield of Serena compared to the other cultivars resulted in better early forage .production as well a legume dominated pasture.
b. Trial 88TS 63 and 88TS 65
Wheat yields following pastures.
Location: 88TS63 - Perenjori and 88TS65 - Three Springs.
There was no response to nitrogen in either biological yield or grain yield of wheat sown over volunteer based pasture at the Three Springs site. All pasture treatments resulted in similar wheat yields except for Sava because of poor control of the snail medic under the …
Introducing Onslow, Western Australian Department Of Agriculture
Introducing Onslow, Western Australian Department Of Agriculture
Grain and other field crops published reports
Onslow Barley........ a new breed of barley for the southern high rainfall areas (see map VH,H4 &H5). Suited to May plantings, Onslow is the first barley developed specifically for the long growing seasons in these areas.
For the first time barley growers have a variety designed for those 4 t/ha plus yields which research shows are possible with early sowing.
Onslow is the first of a new breed of barley cultivars developed in Western Australia specifically for the southern high rainfall areas which have a long growing season.
Lineamenti Geomorfologici Della Costa E Dei Fondali Del Golfo Di Trieste E Considerazioni Sulla Loro Evoluzione Tardo-Quaternaria, Ruggero Marocco
Lineamenti Geomorfologici Della Costa E Dei Fondali Del Golfo Di Trieste E Considerazioni Sulla Loro Evoluzione Tardo-Quaternaria, Ruggero Marocco
International Journal of Speleology
Description of geomorphology of the coasts and the seafloor of the Gulf of Trieste, with paleogeographical discussion on its Late Quaternary evolution.
The Hydrogeology Of A Landfill Located In Fine-Grained Lacustrine Sediments In A Saline Discharge Area West Of Grand Forks, North Dakota, John T. B. Betcher
The Hydrogeology Of A Landfill Located In Fine-Grained Lacustrine Sediments In A Saline Discharge Area West Of Grand Forks, North Dakota, John T. B. Betcher
Theses and Dissertations
The Grand Forks Municipal Landfill, located in the Red River Valley of eastern North Dakota, accepts household refuse from the city of Grand Forks and from surrounding rural communities including several towns in northwestern Minnesota. The landfill occupies 160 acres (64.8 hectars) and another 160 acres (64.8 hectars) is available for expansion. The trench method of disposal is used at the landfill.
A geologic and hydrogeologic investigation was undertaken at the landfill to determine the characteristics of the shallow, saturated, fine-grained lacustrine sediments for solid waste disposal. Test holes were drilled to collect core samples for textural analysis, clay mineralogy …
Environmental Planning Of Large-Scale Water Projects: The Three Gorges Dam Case, China, Long Li
Environmental Planning Of Large-Scale Water Projects: The Three Gorges Dam Case, China, Long Li
Theses and Dissertations (Comprehensive)
Controversy over the construction of the Three Gorges Dam across the Yangtze River in China is an on-going national issue. Proposals have been advanced by numerous disciplinary research teams to identify the environmental consequences of the project development. However, whether the project will benefit or damage the overall environment still remains in question.
No matter which one of the four storage schemes is going to be put into operation, the human, economic, biological, and physical environmental alterations will have no equal in the our contemporary world and probably even for some time in the future. Above all, flood control, hydro-electricity …
The Cultural Eutrophication Of Koontz Lake, Indiana: Causes, Consequences, Correction, Willaim B. Eviston, Thomas Crisman
The Cultural Eutrophication Of Koontz Lake, Indiana: Causes, Consequences, Correction, Willaim B. Eviston, Thomas Crisman
School of Geosciences Faculty and Staff Publications
No abstract provided.
Sulfide In Surface Waters Of The Western Atlantic Ocean, Gregory A. Cutter, Christian F. Krahforst
Sulfide In Surface Waters Of The Western Atlantic Ocean, Gregory A. Cutter, Christian F. Krahforst
OES Faculty Publications
Using newly developed techniques, some preliminary data on hydrogen sulfide in surface waters of the western Atlantic have been obtained. Concentrations of total sulfide range from <0.1 to 1.1 nmol/L, and vary on a diel basis. At these concentrations, sulfide may affect the cycling of several trace metals via the formation of stable complexes. Production of sulfide in oxygenated seawater may occur through the hydrolysis of carbonyl sulfide or by sulfate reduction within macroscopic particles in the water column. Removal mechanisms can include oxidation, complexation with particulate trace metals, and metal sulfide precipitation. However, the temporal and spatial distributions suggest a complex set of processes governing the behavior of sulfide in the surface ocean.
Recent Benthic Foraminifera Of Breton And Stake Islands Northern Gulf Of Mexico, Eric S. Collins
Recent Benthic Foraminifera Of Breton And Stake Islands Northern Gulf Of Mexico, Eric S. Collins
OES Theses and Dissertations
Fifty-three species of recent benthic foraminifera and thecamoebians have been documented and described from the Breton and Stake Island area, northern Gulf of Mexico, and from a core from Barataria Basin, Mississippi delta.
Cluster analysis of benthic assemblages using presence/absence and transformed abundance data reveals the presence of a marsh and shallow water marine biofacies. Based on the results of a presence/absence cluster analysis, the shallow water marine biofacies can be subdivided into a miliolid biofacies am an Ammonia beccarii/Elphidium species biofacies. Cluster analysis of transformed abundance data, however, shows that the shallow marine biofacies can be subdivided into four …
Early Lake Ontogeny Following Neoglacial Ice Recession At Glacier Bay, Alaska, Daniel R. Engstrom, Sherilyn C. Fritz
Early Lake Ontogeny Following Neoglacial Ice Recession At Glacier Bay, Alaska, Daniel R. Engstrom, Sherilyn C. Fritz
Department of Earth and Atmospheric Sciences: Faculty Publications
This study explores the environmental forces controlling lake ontogeny at Glacier Bay as a model for early Holocene lake evolution in north temperate lakes worldwide. Long-term chemical and biological changes in lakes are investigated with two complementary research strategies: (1) limnological conditions are compared among 32 lakes of known age and in different stages of primary catchment succession and (2) sediment cores from these same lakes are analyzed stratigraphically for fossil diatoms to ascertain developmental trends in pH, alkalinity, algal composition, and trophic status at individual sites.
Trends in water chemistry inferred from the chronosequence approach include a progressive loss …
Miscellaneous Production 23/87 - Animal Production In The Spinifex And Shrubland Regions Of Western Australia, D. Burnside
Miscellaneous Production 23/87 - Animal Production In The Spinifex And Shrubland Regions Of Western Australia, D. Burnside
Animal production and livestock published reports
The role of the Rangeland Management Branch is to promote the sustained economic use of the rangeland resource. It provides research and extension services to the pastoral industry, provides advice on the condition of the range resource to Government and provides technical information on rangelands to other rangeland managers. A principal objective to be met in fulfilling that role is the development and promotion of economically efficient place systems that conserve the rangeland resource. At the inaugural Pastoral Soil Conservation Districts Conference in Meekatharra in May 1987, pastoralist delegates emphasized the importance of achieving that objective within the various soil …
Foraminiferal Biostratigraphy And Paleoenvironmental Analysis Of The Anahuac Formation (Late Oligocene-Early Miocene) From A Deep Well In Vermilion Parish, Louisiana, Audrey Lynne Orndorff
Foraminiferal Biostratigraphy And Paleoenvironmental Analysis Of The Anahuac Formation (Late Oligocene-Early Miocene) From A Deep Well In Vermilion Parish, Louisiana, Audrey Lynne Orndorff
OES Theses and Dissertations
In the subsurface of Vermilion Parish, Louisiana, sediments from the Anahuac Formation in the #1 J. W. Steen well are assigned an Upper Oligocene-Lower Miocene age based on planktonic foraminifera. Previous age determinations for sediments from this formation elsewhere range from Middle to Late Oligocene based on the presence of larger foraminifera contained within these strata. Planktonic foraminifera in Anahuac formation sediments in the #1 J. W. Steen well permit their assignment to an established worldwide zonation scheme and indicate that the age ranges from the Globorotalia kugleri Interval Zone (Upper Oligocene) to the Catapsydrax dissimilis Zone (Lower Miocene). Benthic …
Bay/Delta Standards Memorandum And Exhibits, Thomas J. Graff
Bay/Delta Standards Memorandum And Exhibits, Thomas J. Graff
Water Quality Control: Integrating Beneficial Use and Environmental Protection (Summer Conference, June 1-3)
47 pages.
The 1987 Nonpoint Source Pollution Amendments And State Progress Under The New Program, John H. Davidson
The 1987 Nonpoint Source Pollution Amendments And State Progress Under The New Program, John H. Davidson
Water Quality Control: Integrating Beneficial Use and Environmental Protection (Summer Conference, June 1-3)
143 pages.
Contains 4 pages of references.
The San Joaquin–Sacramento Delta, David R. Beringer
The San Joaquin–Sacramento Delta, David R. Beringer
Water Quality Control: Integrating Beneficial Use and Environmental Protection (Summer Conference, June 1-3)
20 pages.
Contains 2 pages of references.
Public Land Livestock Grazing, Water Quality And Riparian Ecosystems: The Evolving Legal And Technical Context, Richard H. Braun
Public Land Livestock Grazing, Water Quality And Riparian Ecosystems: The Evolving Legal And Technical Context, Richard H. Braun
Water Quality Control: Integrating Beneficial Use and Environmental Protection (Summer Conference, June 1-3)
8 pages.
Contains 1 page of references.
Legal Issues: San Francisco Bay, Sacramento-San Joaquin River Delta And Estuary, Stuart L. Somach
Legal Issues: San Francisco Bay, Sacramento-San Joaquin River Delta And Estuary, Stuart L. Somach
Water Quality Control: Integrating Beneficial Use and Environmental Protection (Summer Conference, June 1-3)
48 pages.
Contains footnotes.
Qualitative And Quantitative Aquatic Algal Data Compilation To Determine Macrotrends - Iv, Richard L. Meyer
Qualitative And Quantitative Aquatic Algal Data Compilation To Determine Macrotrends - Iv, Richard L. Meyer
Arkansas Water Resources Center Technical Reports
A data base of the algae of Arkansas ecoregions has been estabblished by the use of a relational data base management system (dBase III plus). The system was chosen to be readily available for a variety of microcomputers using MS- and PC-DOS. The data base contains taxonomic fields from division through variety, synonymy, authors, initial description, date, and definitive descriptive source. The data are cross-referenced by ecoregion, Round's community and subcommunity designations. The data base contains greater than 1,500 taxonomic records in all divisions and classes of freshwater algae. The data are sortable by any of the included parameters. The …
Patterns Of Sulfur Deposition In The Wood Of Pinus Echinatia Mill. From The Cumberland Plateau In Kentucky, Darrell Ray
Patterns Of Sulfur Deposition In The Wood Of Pinus Echinatia Mill. From The Cumberland Plateau In Kentucky, Darrell Ray
Masters Theses & Specialist Projects
Air pollution and acid precipitation have long had an influence on plant and animal life. In this study, the level of sulfur in the stem tissue of Pinus echinata Mill. was measured in trees from various sites along the western edge of the Cumberland Plateau to determine the presence and pattern of sulfur deposition in this species. Overall, a 40.28% increase in sulfur levels was observed from four sites along the plateau with levels increasing from 0.072 mgS/gdwt in the 1962-66 growth increment to 0.101 mg in the 1982-86 increment. According to a computer generated analysis of variance, the differences …
Long-Term Reconstruction And Analysis Of White River Streamflow, M. K. Cleaveland, D. W. Stahle, J. G. Hehr
Long-Term Reconstruction And Analysis Of White River Streamflow, M. K. Cleaveland, D. W. Stahle, J. G. Hehr
Arkansas Water Resources Center Technical Reports
A 281-year reconstruction of White River annual runoff at Clarendon, Arkansas, was developed from a regional average of nine Oklahoma, Missouri, and Arkansas tree-ring chronologies (six post oak, Quercus stellata, and three baldcypress, Taxodium distichum). Inhomogeneity of the gaged series was detected with both double mass analysis (using state average total annual Arkansas precipitation) and regression (using the regional tree-ring average). Simple regression calibrated the homogeneous runoff data with the average ring width data from 1930 to 1980. Comparing the reconstruction with independent data verified the regression model. Variance of the reconstruction increases significantly during the 20th century, a change …