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Articles 3601 - 3630 of 3635

Full-Text Articles in Other Environmental Sciences

Spectral Irradiance In Nebraska Reservoirs And A New Instrument For Its Measurement, Gary D. Uphoff Aug 1973

Spectral Irradiance In Nebraska Reservoirs And A New Instrument For Its Measurement, Gary D. Uphoff

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.


Changes In Polysomes Of Black Locust Seedlings During Dehydration-Rehydration Cycles, James R. Brandle, P.D. Schnare, T.M. Hinckley, G.N. Brown Jan 1973

Changes In Polysomes Of Black Locust Seedlings During Dehydration-Rehydration Cycles, James R. Brandle, P.D. Schnare, T.M. Hinckley, G.N. Brown

School of Natural Resources: Faculty Publications

No abstract provided.


Chronic Toxicity Of A Copper, Cadmium And Zinc Mixture To The Fathead Minnow (Pimephales Promelas Rafinesque), John G. Eaton Jan 1973

Chronic Toxicity Of A Copper, Cadmium And Zinc Mixture To The Fathead Minnow (Pimephales Promelas Rafinesque), John G. Eaton

United States Environmental Protection Agency: Publications

Fathead minnows were exposed to a series or concentrations of a copper, cadmium and zinc mixture during a 12.5 month chronic test in water of 200 mg 1-1 total hardness. The metal concentrations in the mixture were selected on the basis of results obtained during previous chronic exposures to each of the metals individually in the same water. Strict summation of the chronic toxicities of the metals was not indicated when they were tested in combination. Toxic effects of the mixture attributable to copper appeared to be increased, but that attributable to cadmium was reduced. The effects thought to …


Captan Toxicity To Fathead Minnows (Pimephales Promelas), Bluegills (Lepomis Macrochirus), And Brook Trout (Salvelinus Fontinalis), Roger O. Hermanutz, Leonard H. Mueller, Kenneth D. Kempfert Jan 1973

Captan Toxicity To Fathead Minnows (Pimephales Promelas), Bluegills (Lepomis Macrochirus), And Brook Trout (Salvelinus Fontinalis), Roger O. Hermanutz, Leonard H. Mueller, Kenneth D. Kempfert

United States Environmental Protection Agency: Publications

The toxic effects of capt an on survival, growth, and reproduction of fathead minnows (Pimephales promelas) and on survival of bluegiIIs (Lepomis macrochirus) and brook trout (Salvelinus fontinalis) were determined in a flow-through system. In a 45-week exposure of fathead minnows, survival and growth were adversely affected at 39.5 μLg/Iiter. Adverse effects on spawning were suspected but not statisticaIly demonstrated at 39.5 and 16.5 μLg/Iiter. The maximum acceptable toxicant concentration (MATC), based on survival and growth, lies between 39.5 and 16.5 μLg/liter. The lethal threshold concentration (LTC) derived from acute exposures was 64 μLg/liter, …


Chronic Effect Of Low Ph On Fathead Minnow Survival, Growth And Reproduction, Donald I. Mount Jan 1973

Chronic Effect Of Low Ph On Fathead Minnow Survival, Growth And Reproduction, Donald I. Mount

United States Environmental Protection Agency: Publications

Fathead minnows (Pimephales promelas Rafinesque) were continuously exposed to reduced pH levels of 4.5, 5.2, 5.9, 6.6 and 7.5 (control) during a 13-month, one-generation test. Survival was not affected, even at the lowest pH tested. Fish behavior was abnormal, and fish were deformed at pH 4.5 and 5.2. Egg production and egg hatchability were reduced at pH 5.9 and lower, and all eggs were abnormal. A pH of 6.6 was marginal for vital life functions, but safe for continuous exposure. Free carbon dioxide, liberated by the addition of sulfuric acid to reduce the pH, may have had an unknown …


Regional Hydrothermal Alteration Of The Leadville Limestone (Mississippian) Of Central Colorado, L. V. Benson Jan 1973

Regional Hydrothermal Alteration Of The Leadville Limestone (Mississippian) Of Central Colorado, L. V. Benson

United States Geological Survey: Staff Publications

Massive metallic-sulfide deposits were implaced in the Leadville Limestone {Mississippian) of Central Colorado less than 70 million years ago. The thermal fluids which precipitated ore at Gilman, Colorado have regionally altered the Leadville Limestone. The sequence of alteration began with the recrystallization of limestone to a dark medium~grained dolomite containing a homogeneous distribution of Fe. This Was followed by partial recrystallization of the medium-grained dolomite to coarse-clear dolomite which contains an inhomogeneous distribution of Fe. The resulting banded rock is known as "zebra rock" . Precipitation of Si0 2 (jasperoid) occurred next. The jaspe=oid formed prior to the deposition of …


Eutrophication Factors In North Central Florida Lakes, H. D. Putnam, Patrick L. Brezonik, Earl E. Shannon Feb 1972

Eutrophication Factors In North Central Florida Lakes, H. D. Putnam, Patrick L. Brezonik, Earl E. Shannon

United States Environmental Protection Agency: Publications

A small Florida lake has been receiving a regimen of nutrient addition equivalent to 500 mg/m3-yr N and 43 mg/m3-yr P since 1967. Data has been accumulated through 1969. The effect on the lacustrine ecosystem of various biogenes includes production by primary producers, species diversity of plankton and certain production estimates at the secondary trophic level using natural populations of planktivorous fish. Plankton production using isotopic carbon is ca. 58 grms/m2-yr; Species diversity is slowly changing to a mixed chlorophycean and yellow-green. Biomass of benthic green filamentous types has increased slightly. Nutrient addition has …


Simultaneous Determination Of Short-Period Photosynthesis And Evapotranspiration (Horticulture And Forestry Progress Report No. 91), Norman J. Rosenberg Jan 1972

Simultaneous Determination Of Short-Period Photosynthesis And Evapotranspiration (Horticulture And Forestry Progress Report No. 91), Norman J. Rosenberg

School of Natural Resources: Faculty Publications

No abstract provided.


An Argument For The Open Ocean Siting Of Coastal Thermal Electric Plants, Clarence M. Tarzwell Jan 1972

An Argument For The Open Ocean Siting Of Coastal Thermal Electric Plants, Clarence M. Tarzwell

United States Environmental Protection Agency: Publications

A great deal of research is yet to be done before we will definitely know all the effects of thermal electric generating plants. It is evident, however, that the chlorination of the intake water is definitely lethal to a high percentage of planktonic and other organisms; that thermal shock is detrimental to some of the more sensitive forms; that the continued exposure to high temperatures after thermal shock is lethal to many forms, especially the zooplankton; that the screening and turbulence in such plants is lethal to larval fishes and several invertebrates, and that immense amounts of waters are put …


Response Of Fraxinus Pennsylvanica M. Provenances To Daylength And Temperature, Cheng-Chun Ying Dec 1971

Response Of Fraxinus Pennsylvanica M. Provenances To Daylength And Temperature, Cheng-Chun Ying

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.


A Study Of The Limnetic Zooplankton Of Five Flood Control Reservoirs, Glen R. Helzer Aug 1971

A Study Of The Limnetic Zooplankton Of Five Flood Control Reservoirs, Glen R. Helzer

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.


Final Report Emission Inventory For The State Of Nebraska, The Ibm Corporation Federal Systems Division, Environmental Protection Agency Jul 1971

Final Report Emission Inventory For The State Of Nebraska, The Ibm Corporation Federal Systems Division, Environmental Protection Agency

United States Environmental Protection Agency: Publications

The following report represents the results of the work performed under BOA 68-02-0043, Task Order Number 1 from The Environmental Protection Agency, Air Pollution Control Office. A note of thanks is due to Mr. E. J. Lillis and D. Dunbar of the EPA Project Office and Mr. Peter Culver, the EPA Project Engineer for their assistance and excellent cooperation during the study. A note of special thanks is due to Mr. Gene Robinson of the Nebraska Division of Air Pollution Control without whose efforts successful completion of this task would not have been possible.


Numerical Computer Perpheral Interactive Device With Manual Controls, James C. Fletcher, Arthur I. Zygielbaum, Stanley S. Brokl Jun 1971

Numerical Computer Perpheral Interactive Device With Manual Controls, James C. Fletcher, Arthur I. Zygielbaum, Stanley S. Brokl

School of Natural Resources: Faculty Publications

A computer peripheral device is disclosed which in cludes a joystick whose displacement from a center position along two axes X and Y in either a plus (+) or a minus (-) direction is sensed. The displacement magnitude in either direction controls the rate of clock pulses provided by a variable frequency clock. The clock pulses from the two clocks are accumulated in two separate counters, whose contents are dis played. The contents of the counters are suppliable to a computer to update the contents of specific cells which define the position of a cursor on a display which is …


Real Property Owned. By The Federal Government In The' State Of Nebraska, U.S. Environmental Protection Agency Jun 1971

Real Property Owned. By The Federal Government In The' State Of Nebraska, U.S. Environmental Protection Agency

United States Environmental Protection Agency: Publications

This inventory report Is a summary compilation of the major facilities of real property owned by the Federal Government in this state. The installations are listed alphabetically by the city in which they are located and the listing includes a brief description of the installation, the agency which operates the facility, the GSA inventory number, the GSA location code, the total floor area of all the buildings and a size classification code. The operating agency and Installation descriptions are those reported to the General Services Administration as of June 30, 1970. Installations with a total floor area less than 1,500 …


Bioassay Procedures For Oil And Oil Dispersant Toxicity Evaluation, Gilles Laroche, Ronald Eisler, Clarence M. Tarzwell Nov 1970

Bioassay Procedures For Oil And Oil Dispersant Toxicity Evaluation, Gilles Laroche, Ronald Eisler, Clarence M. Tarzwell

United States Environmental Protection Agency: Publications

Hazards to marine and estuarine fauna associated with offshore drilling of oil and with transport of large quantities of oils via tankers are numerous and understandable. At present, there is a growing body of evidence on adverse effects to these organisms of crude oil (1) (2) (3) (4) (5) (6) (7) (8) (9) and chemical oil counteracting agents or dispersants (5) (6) (9) (10) (11) (12) (13) (14) (15) (16) (17). These effects are well summarized by Smith (18) and by Carthy and Arthur (19).

Comparatively few workers have studied the influence of oil-dispersant mixtures of marine life. Studies by …


Thermal Requirements To Protect Aquatic Life, Clarence M. Tarzwell May 1970

Thermal Requirements To Protect Aquatic Life, Clarence M. Tarzwell

United States Environmental Protection Agency: Publications

Water temperatures affect aquatic organisms in a number of ways, both directly and indirectly. Some of the latter effects are quite subtle. High temperatures can have direct lethal effects but sublethal levels operating over long periods can be just as harmful through delayed lethal effects and the production of nonlethal stresses which eventually result in changes in the population, reduced growth or reproduction, and the lowering of resistance to parasites, dis ease, and competitors. Temperature, in combination with certain other factors such as day length, influences re producing processes. High water temperatures may stimulate or retard migration, spawning, feeding, and …


Concentration Of Co, In The Air Above A Sugar Beet Field, K.W. Brown, Norman J. Rosenberg Jan 1970

Concentration Of Co, In The Air Above A Sugar Beet Field, K.W. Brown, Norman J. Rosenberg

School of Natural Resources: Faculty Publications

The concentration of CO, in air sampled above a sugar beet crop was measured during July, August, and early September 1966 at Scottsbluff, Nebr. During July the mean daytime concentration decreased from 310 ppm to 283 ppm as the leaf area index increased from 0.8 to 4.0. Only small deviations from the mean daytime Concentration of 283 ppm occurred during the remainder of the season. The mean nocturnal concentration during this period was 320 ppm and was more variable than the daytime concentration. The daily amplitude of concentration averaged 70 ppm and was as great at times as 100 ppm. …


Agroclimatic Calendar For Nebraska, R. E. Neild Feb 1968

Agroclimatic Calendar For Nebraska, R. E. Neild

School of Natural Resources: Faculty Publications

Crops are planted so growth, development and harvest correspond closely to the season most favorable for yield and quality. With exception of fall-seeded small grains and some forages, most Nebraska crops are planted in the spring when temperature and precipitation are increasing.


Ultrasonic Tracking Of Migratory Fishes With An Internal Tag, Ross M. Horrall, H. F. Henderson, A. D. Hasler Sep 1965

Ultrasonic Tracking Of Migratory Fishes With An Internal Tag, Ross M. Horrall, H. F. Henderson, A. D. Hasler

School of Natural Resources: Faculty Publications

First paragraph:

A small ultrasonic tag, 9 mm by 40 mm in size, has been developed by members of the fish orientation group at the University of Wisconsin. The tag emits a continuous signal at approximately 65 kc/sec. The signal is received via a directional hydrophone and a high quality communications receiver. Tracking ranges of up to 1 km have been obtained. The placement of the tag is internal: either into the stomach or into the body cavity of the fish. The tags and tracking equipment have been successfully employed in studies on the open water movements and orientation of …


Development Of Water Quality Criteria For Aquatic Life, Clarence M. Tarzwell Nov 1962

Development Of Water Quality Criteria For Aquatic Life, Clarence M. Tarzwell

United States Environmental Protection Agency: Publications

It is now recognized that water pollution is an important problem, that it becomes more widespread and serious as population and industry expand, and that something must be done if aquatic life resource are to be saved and their productivity maintained. In the past there has been a great deal of uncertainty in approaching this situation and a general lack of understanding of the details and ramification of the overall problem. In the efforts for the abatement of pollution, only a few clearcut objectives have been established. Knowledge is lacking as to what the objectives should be. There is still …


Industrial Wastes: Bio-Assays For Control Of Industrial Effluents, Croswell Henderson, Clarence M. Tarzwell Sep 1957

Industrial Wastes: Bio-Assays For Control Of Industrial Effluents, Croswell Henderson, Clarence M. Tarzwell

United States Environmental Protection Agency: Publications

Waste effluents from many industries are toxic to fish and other aquatic life. The control or treatment of these wastes for safe release into receiving waters presents a problem of consider able magnitude.

Much effort has been expended by some industries to solve this problem, primarily through chemical analysis for possible toxic components and then generally by a search of the literature to find out how toxic a particular component may be. Unfortunately, this approach has not been successful, nor can it be expected to be productive of satisfactory answers.


Stream Pollution- Aquatic Macro-Invertebrate Communities As Indicators Of Organic Pollution In Lytle Creek, Arden R. Gaufin, Clarence M. Tarzwell Jul 1956

Stream Pollution- Aquatic Macro-Invertebrate Communities As Indicators Of Organic Pollution In Lytle Creek, Arden R. Gaufin, Clarence M. Tarzwell

United States Environmental Protection Agency: Publications

Year-round field studies of the com position and ecology of stream communities associated with the purification of organic wastes in streams were initiated on Lytle Creek in October, 1949. This creek, which is located about 45 miles northeast of Cincinnati, Ohio, is a tributary of the Little Miami River. Its drainage basin comprises 27 sq. mi., a third of which is contained within the city limits of Wilmington, Ohio, a city of some 7,412 persons


Industrial Wastes, Charles E. Renn Mar 1955

Industrial Wastes, Charles E. Renn

United States Environmental Protection Agency: Publications

This paper presents a summary of experiences with a variety of cyanogenic wastes. The work has attempted to evaluate the interaction of waste bearing waters and the environment in terms of waste disposal design requirements. In this, the approach is somewhat more critical than that commonly taken by fisheries biologists, conservationists, and others who have been concerned with the "preventive" aspects of waste disposal.

The first phases of the work were designed to discover the tolerable limits of certain waste components to fresh water fish. This was undertaken in 1950; in the interval the composition of the wastes has been …


Stream Pollution, Ruth Patrick Feb 1953

Stream Pollution, Ruth Patrick

United States Environmental Protection Agency: Publications

This paper discusses the various ways in which aquatic organisms may be of use in solving problems associated with waste disposal. Since many state and federal laws set forth that nothing may be discharged that is deleterious to aquatic life, the most expedient way to determine the effect of an effluent is to study the aquatic organisms themselves.

In every river that has not been adversely affected by pollution there is a great variety of aquatic life. These organisms do not represent a great mass of living things, but rather they are organized into an intricately balance systems, often referred …


A Subsurface Study Of The Pleistocene Deposits In Kearney County And Adjoining Parts Of Adams, Franklin, And Webster Counties, Vincent H. Dreeszen Jun 1950

A Subsurface Study Of The Pleistocene Deposits In Kearney County And Adjoining Parts Of Adams, Franklin, And Webster Counties, Vincent H. Dreeszen

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.


It's Time To Take Stock Apr 1950

It's Time To Take Stock

United States Environmental Protection Agency: Publications

Likening colleges and universities to the automobile industry may seem far-fetched, but is it? Each is engaged in fashioning and selling necessary products- one trained men, the other mechanical equipment. Both entered the post-war years with production at low ebb; unable to satisfy pent-up customer demands. Time and high-speed assembly lines have bridged the gap of gas buggy shortage. The impact of selective buying by a discriminating public is now real cause for concern among some of the motor moguls. Rumor has had it that schools teaching wildlife management are overproducing. We decided to gather facts and opinions at the …


Public Health Reports, Clarence M. Tarzwell Feb 1950

Public Health Reports, Clarence M. Tarzwell

United States Environmental Protection Agency: Publications

Preliminary tests with DDT for the control of mosquitoes, forest insects, and agricultural pests demonstrated that it was toxic to a wide variety of animal life. Because there were indications that the new insecticide would be widely used, apprehension was expressed by some groups that its extensive or indiscriminate use would cause extensive harm to wildlife.

The desirability of carefully controlled use was early recognized by those in charge of extensive programs for the control of insects of public health importance. A joint statement of policy for the use of DDT issued early in 1945 (1) by the Army and …


Observations On The Nighttime Resting And Biting Habits Of Anopheline Mosquitoes In Ddt-Treated And-Untreated Buildings, Clarence M. Tarzwell, Frank W. Fisk Jan 1947

Observations On The Nighttime Resting And Biting Habits Of Anopheline Mosquitoes In Ddt-Treated And-Untreated Buildings, Clarence M. Tarzwell, Frank W. Fisk

United States Environmental Protection Agency: Publications

Laboratory cage tests and controlled experiments in houses have clearly demonstrated that residual-spray deposits of DDT are lethal to mosquitoes for considerable periods. Although these tests valuable information on the durability of DDT residual deposits, they did not give information on the mortality of malaria mosquitoes naturally entering treated dwellings in search of a blood meal. In order to secure a lethal dose of DDT from residual deposits, mosquitoes must actually touch the material and be exposed to it for a considerable period. This period has been shown to vary (1), depending on the temperature, age of treatment, density and …


The Feeding Habits Of Gambusia Affinis Affinis, With Special Reference To The Malaria Mosquito, Anopheles Quadrimaculatus, A.D. Hess, Clarence M. Tarzwell Jun 1941

The Feeding Habits Of Gambusia Affinis Affinis, With Special Reference To The Malaria Mosquito, Anopheles Quadrimaculatus, A.D. Hess, Clarence M. Tarzwell

United States Environmental Protection Agency: Publications

The viviparous top minnow, Gambusia affinis affinis (Baird and Girard), has for many years been considered an important predator of the immature stages of mosquitoes. Various field workers have reported on the value of this species in controlling both anopheline and culicine mosquitoes, but few detailed studies have been made. Probably the most detailed of these has been that of Hildebrand (1925). His investigations were made during the summers of 1921-24 in the vicinity of Augusta, Ga., with the subspecies G. affinis holbrooki. Employing the common dipper method, he compared the densities of anopheline and culicine larvae and pupae in …


An Analysis Of Fishing In The Tva Impoundments During 1939, R. William Eschmeyer, Clarence M. Tarzwell Jan 1941

An Analysis Of Fishing In The Tva Impoundments During 1939, R. William Eschmeyer, Clarence M. Tarzwell

United States Environmental Protection Agency: Publications

An inventory of fishing on Norris, a storage reservoir, was begun in 1938. The following year it was extended to Wheeler, a run-of-the-river reservoir, and to the tailwater area below Wilson Dam. This inventory, therefore, covered each of the three general types of fish habitats created by the TVA dams. This discussion is a summary of the 1939 fishing data, together with recommendations for fish management based on the creel census information. The data collected totaled 34,270 usable fishing records, representing a catch of 98,495 fishes.