"In order to gain an adequate idea of the sanitary condition of the drinking fountains on the North Texas State Teachers College campus, it was found necessary to approach these bacteriological studies from a seasonal point of view."--1.

"The purpose of this study is to gather information concerning some factors which may have operated to influence science majors in North Texas State College toward science careers."--4.

The purpose of this study is to gather information related to the characteristics of two groups of undergraduate non-science majors; namely, those students who once considered science as a career and subsequently changed to a non-science major and those who have never considered a career in science. It is frequently observed that children in the elementary school have an intense interest in science. One of the principal concerns of this study is how and for what reasons has the interest in science changed between elementary school and college? It is also the purpose of this study to gather information related to the attitudes of these college students toward the science courses they have had in high school and toward their science teachers. In attempting to arrive at an answer, the group who once considered a science career and those who have never considered an occupational choice in a field of science will be compared in the following areas: 1. General information such as sex, age, size of high school attended, rank within their graduating classes, college classification and military experiences. 2. Occupations and hobbies of parents. 3. Experiences which may influence attitudes toward science such as elementary school science, high …

Rates of primary production and community metabolism were monitored over a one year period using the diurnal oxygen method. Certain physico-chemical parameters were also measured, and autotrophic standing crops were estimated. An in-depth study was made of the phytoplankton community and various diversity indicies were calculated. Simple correlations were run between all parameters measured (biotic and abiotic), and their inter-relationships examined. Multiple linear regression analyses were used to develop equations predictive of production and community metabolism. Bluegreen algae were the dominant phytoplankters with blooms occurring in late summer and fall. Yearly mean production was approximately 21 kcal per meter square per day with a mean photosynthetic efficiency of 1.2 per cent. Of the various parameters measured turbidity and water temperature were most important in determining rates of primary production.

The problem with which this investigation was concerned was the comparison of cedar elm populations in different stands along creeks in Denton County, Texas, and the relationship of certain population parameters to various substrates present at stand sites, Parameters investigated eluded average basal area, basal-area density, transect-segment density, intertree distance, lateral distance, frequency, diameter breast-high, diameter breast-high size-class distribution, and immature-tree density. Variations among populations of Ulmus crassifolia Nutt were noted and analyzed in terms of soil particle size and existing community conditions.

"As a means of defining the purpose of the problem, the following objectives were considered: (1) to list the species of birds observed in Denton and neighboring counties; (2) to assign a descriptive status to each species; (3) to estimate the relative abundance of each species (4) to annotate the list with data from other sources, when additional data provide a more accurate and complete description of the status of the species in Denton County; (5) to designate the section of the county in which each species was most frequently observed; and (6) to briefly summarize the changes in bird populations during the period 1950-1956, and to suggest some hypotheses which help explain these changes." -- leaf 6.

Seven species of planktonic microcrustacea were identified from the North Texas State University Golf Course Pond. Total adult microcrustacean community density, biomass and biocontent, and seasonal cycles of each species were compared with northern populations. Species diversity and evenness indices were highest in summer and lowest in spring. Variations in microcrustacean density showed a positive correlation with density of phytoplankton. Temperature had a direct effect on metabolic rates of two species of copepods. Metabolic rates of pond species were lower at common temperatures than those of northern populations. An estimate of annual energy flow through the pond ecosystem showed cladocerans contributed the greater percentage of total energy to the next trophic level.

The City of Denton Pecan Creek Wastewater Treatment Facility has periodically failed effluent toxicity testing. A Toxicity Identification Evaluation has determined that Diazinon in the effluent is contributing to the observed toxicity. Chlorpyrifos is also implicated as a factor. The City of Denton constructed a half acre experimental wetland to remove Diazinon related toxicity. Results from spiking and microcosm experiments indicate that the wetland can reduce the Diazinon.

Two years before impoundment, the trophic status of Lake Ray Roberts was predicted by applying the total phosphorus input into the Organization for Economic Cooperation and Development (OECD) eutrophication model. Predicted mean summer epilimnetic (MSE) chlorophyll a of Elm Fork arm, Isle duBois arm and Main Body were in the eutrophic category of the OECD model. Observed MSE chlorophyll a two years after impoundment of Elm Fork arm, Isle duBois and Main Body had not reached their predicted means and were at the mesotrophic-eutrophic boundary of the OECD model. Six years after impoundment, observed MSE chlorophyll a for Main Body, was closer to its predicted mean and in the eutrophic category of the OECD model. Six years after impoundment, Elm Fork arm was the most productive area of Lake Ray Roberts. Observed means of chlorophyll a, total phosphates, suspended solids and turbidity were often highest in the Elm Fork arm. Wastewater effluent from Gainesville and Valley View, TX, had an impact on productivity in Elm Fork arm.

Canonical correspondence analysis (CCA) was used to explore relationships between measured environmental variables and in situ phytoplankton communities in a moderately eutrophic North Texas Reservoir.

A large, multi-basin, reservoir (Garza-Little Elm Reservoir) in north central Texas was studied to determine the relative effects of various parameters on primary productivity. The basins were impounded several years apart,thus allowing the influence of age on water chemistry and biota to be considered. Another principal influence on water quality was secondary sewage effluent that entered one basin from a nearby source.

This study examined the effects of replicating woodland soil surface horizonation on the nutrient status of underlying soils and the initial establishment and growth of trees. A total of 283 container grown trees were planted in a bufferzone around a future landfill site. Control amendments consisted of an 8 cm layer (0.5 m3) of wood chips applied in a circular area of 4.6 m2 around the trees' planting pit. For the treatment, a 2.5 cm layer of composted biosolids (0.15 m3 or 80 Mg/ha) was applied in a circular area of 4.6 m2 around the trees' planting pit followed by an 8 cm layer (0.5 m3) of wood chips. The results indicate that the replication of woodland soil surface attributes using composted biosolids can significantly improve the nutrient status of underlying soil. Some significant effects were seen under control conditions, too. However, the effects on tree establishment and growth parameters were, for the most part, not statistically significant.

It was the purpose of this investigation to attempt to demonstrate if differences in eutrophic levels existed among selected areas of Garza-Little Elm, and to demonstrate the role that sediments play in affecting eutrophication.

Actinomycetes are able to utilize a great variety of carbohydrates, like sugar. The particular kind of sugar and its concentration has decisive effect on the growth of microorganisms. The proper nutritional media aids also in the production of spores. Based on this generalization, that the growth and sporulation of microorganisms are greatly influenced by the nature and the concentration of carbohydrates, an attempt has been made to study Actinoplanes philippinensis with respect to this influence.

This thesis describes the present nature of one facet of some of the flood plain forest stands in Denton County, Texas. The specific purpose was to demonstrate the presence or absence of difference between the Celtis laevigata (commonly known as the hackberry, southern hackberry or sugarberry) populations in stands on Denton Creek and Elm Fork of the Trinity River.

In this study, branchiobdellids were collected from crayfish captured from two adjacent sites in Denton County, Texas. Identification of the branchiobdellid, Cambarincola vitrea Ellis, was first made and then work was extended to include several topics of ecological interest.

The purpose of the present study was to determine the relative importance of aquatic and terrestrial beetles as possible vehicles in the passive overland dispersal of viable microorganisms.

This study had a three-fold purpose. First, it was decided to determine if algae and protozoa were emitted to the air at the Denton sewage treatment plant. The information obtained could be of future importance in the fields of algal and protozoan ecology and public health. Second, it was decided to make a survey of the airborne bacteria at this plant. Some researchers have described bacterial air contamination at similar sewage treatment plants, but the one in Denton has not been studied. Third, it was hoped that in this research some relationships could be found between the bacteria and the algae and protozoa in the air in the vicinity of the sewage aeration basin. It was hypothesized that pathogenic bacteria were carried in the air with these other organisms.

The purpose of this study was threefold. The literature concerning parasites of A. crepitans was to be brought up to date. Contributions to the general body of knowledge pertaining to the parasitic fauna of host specimens of A. crepitans and specifically those found in Denton County, Texas, were to be made. Finally, specimens found parasitizing host specimens of A. crepitans were to be preserved and classified.

The purpose of this study is to determine the presence or absence of a typical Krebs cycle metabolism in the primary mycelia of an aquatic streptomycete.

The purpose of this paper is to detail the distribution and quantity of soluble phosphates in an activated sludge plant, its discharge creek, and receiving reservoir. The resultant analyses and comparison of data should provide some better understanding of the fate of phosphorus in a Southwestern waterway system.

The removal of phenols from the waste waters of wood preserving plants has always presented problems. The purpose of this paper is to investigate the possibility of employing a biological system to reduce the phenol content of effluent from these plants.

The purpose of this study was to demonstrate the variability of oxygen and carbon dioxide rate of change methods for measuring primary productivity and respiration in an aquatic environment.

It was the purpose of this investigation to present laboratory data concerning the assimilation of inorganic nitrogen by the aquatic actinomycetes. The strains of aquatic actinomycetes under consideration represented a cross section of those currently under culture at North Texas State University.