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Responses of Pristina leidyi Smith 1896 (Naididae: Oligochaeta) to Cadmium, Vanadium, and Some Environmental Factors

Description: Concern over sediment toxicity has increased the need for toxicity test information with organisms that inhabit sediments. Oligochaetes are exposed to toxicants through feeding and direct body contact with aquatic sediments. Chronic testing with oligochaetes has historically focused on tubificids with test lengths of one year or more to encompass several generations. Most naidid oligochaetes have generation times of three to seven days and could provide chronic information in a matter of weeks.… more
Date: May 1990
Creator: Smith, David P. (David Paul), 1956-
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Interactions among Temperature, pH, and Cyfluthrin on Survival of the Fathead Minnow Pimephales promelas

Description: The 96-hr LC50 of cyfluthrin in Pimephales promelas ata temperature of 23*C and a pH of 8 was 1.08 g/L. The toxicity of cyfluthrin was inversely related to temperature and pH. A temperature of 10*C and a pH of 6 significantly decreased the 96-hr LC50 to 0.009 gg/L. Likewise, sublethal exposures to cyfluthrin significantly affected the fathead minnow's ability to tolerate high and low temperatures. Cyfluthrin compromised the fathead minnow's lower temperature tolerance (CTMin) by 60C and the upp… more
Date: December 1991
Creator: Heath, Susan M.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Remote Sensing of Landscape-Level Ecological Attributes at Ray Roberts Lake in North Texas

Description: Biological diversity is a key component in assessing ecosystem health. Alteration, degradation and loss of habitat due to human influence is currently the primary stressor resulting in decreases in diversity. Reliable assessment of large areas in terms of biological integrity are needed for conservation and preservation efforts. Remotely sensed data provide an integrated view of reflected electromagnetic energy over large areas of the earth. These energy patterns provide unique spectral signatu… more
Date: December 1997
Creator: Smith, David P. (David Paul), 1956-
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Evaluation of Diet, Water, and Culture Size for Ceriodaphnia Dubia Laboratory Culturing

Description: Six reagent waters, eleven diets, and two culture sizes were evaluated for culturing C. dubia. Different filtration techniques were used to prepare the reagent waters. The eleven diets were comprised of two algae augmented with eight supplements. Reproduction and growth were assessed to discern differences among C. dubia raised in mass cultures and cultured in individual cups, during which, bacterial population densities, lipid, protein, and carbohydrate concentrations of the diets were measure… more
Date: December 1992
Creator: Allen, Jerry D. (Jerry Dee)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Pyrethroid Insecticide Effects on Bluegill Sunfish (Lepomis Macrochirus) and the Impacts of Bluegill Predation on Invertebrates in Microcosms

Description: Concurrent outdoor aquatic 1950 L microcosm and 0.04 ha mesocosm experiments with bluegill sunfish evaluated the ecological impact of cyfluthrin. Cyfluthrin effects were not observed on mesocosm bluegill; a slight decrease in growth was observed in the microcosm bluegill. Otolith weight to length relationships between bluegill size-classes from microcosms, local streams, and a fish hatchery revealed no differences. Our results indicated bluegill predation impacts were slight on benthic inverteb… more
Date: May 1991
Creator: Morris, Rodney Gregg
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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A Water Quality and Ecological Survey of the Trinity River, Volume 2

Description: This volume of the report represents the technical findings of a study conducted on the ecological makeup of the Trinity River. The data presented includes: ambient toxicity test results and survival rates, United States Geological Survey (USGS) flow data, water quality data, as well as sediment quality data.
Date: November 1989
Creator: University of North Texas. Institute of Applied Sciences.
Item Type: Refine your search to only Report
Partner: UNT Institute of Applied Sciences
open access

Effects of Water Quality, Instream Toxicity, and Habitat Variability on Fish Assemblages in the Trinity River, Texas

Description: The Trinity River flows through the Dallas-Ft. Worth Metroplex in north central Texas where it receives effluents from numerous point sources including seven large regional wastewater treatment facilities. Historically, the Trinity River has been impacted by massive wastewater loadings which often constitute > 80% of the total river discharge during low flow periods. Normally, high mass loadings correspond to the summer months, compounding the effects of a naturally stressful period, characteri… more
Date: December 1989
Creator: Arnold, Winfred R., 1960-
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Assessment of Changes in Aquatic Macrophyte Occurrence Following Introduction of Triploid Grass Carp in a North Texas Reservoir

Description: The objectives of this project were to measure changes in frequency of occurrence of submerged macrophytes over the first two growing seasons following stocking with triploid grass carp at two fish per acre and to measure differences in macrophyte biomass between areas excluded from herbivory and adjacent control sites after 16 months following establishment of exclosures. The project also seeks to measure concentrations of fluridone following the herbicide treatment, and to compare two methods… more
Date: August 1997
Creator: Bickel, Ken (Kenneth E.)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Combined Effects of Polycyclic Aromatic Hydrocarbons and Ultraviolet Light on Benthic and Pelagic Macroinvertebrates

Description: Crude oil commonly enters freshwater aquatic ecosystems as thin sheens forming on the water surface. Oil contains mixtures of toxic compounds called polycyclic aromatic hydrocarbons (PAHs), some of which are known to be photodynamic, increasing toxicity when combined with ultraviolet radiation. Benthic macroinvertebrate communities are commonly utilized as bioindicators, and as such rely on abundant data in literature concerning benthic macroinvertebrates' relative tolerances to a wide range of… more
Date: May 2023
Creator: Chapman, Abigail L.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Effect of pH on the Persistence and Toxicity of Cyfluthrin to Chironomus Tentans

Description: The effect of pH upon the aquatic toxicity of cyfluthrin was determined in 48 h static acute toxicity tests using 2nd instar Chironomus tentans larvae. Tests were conducted in both dechlorinated tap water and lake water of pH 8.0, 7.2, and 6.6. After 48 h, immobilized and dead larvae were removed and replaced with 2nd instar larvae to assess the persistence of toxicity. Midges were cultured in water adjusted to the pH values used in testing. Toxicity if cyfluthrin varied inversely with pH. An i… more
Date: May 1992
Creator: Hambleton, Faith Ann (Faith Ann Elizabeth)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Dissolved Organic Carbon Assessment on Selected Creeks and Rivers within the Elmfork Subwatersheds of Denton, Texas

Description: The primary focus of the study was to compare dissolved organic carbon (DOC) at baseline stream flow to DOC at a higher post-rain stream flow, with a secondary focus on comparison of DOC between sites. Comparisons were also done on suspended solids at baseline flow to those of the higher post-rain flow, as well as suspended solids between sites. Significant differences did exist between DOC sampled at baseline flow and DOC in samples taken at peak flow. The study found no difference in suspende… more
Date: May 2004
Creator: Jackson, Pamela J.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Sumergidos Con Lupa en Los Ríos Del Cabo De Hornos: Valoración ética De Los Ecosistemas Dulceacuícolas Y Sus Co-Habitantes

Description: This article presents the methods and results of a multidisciplinary work focused on invertebrates and freshwater ecosystems of the Cape Horn Biosphere Reserve.
Date: June 25, 2018
Creator: Contador, Tamara; Rozzi, Ricardo, 1960-; Kennedy, James H.; Massardo, Francisca; Ojeda, Jaime; Caballero, Paula et al.
Item Type: Refine your search to only Article
Partner: UNT College of Liberal Arts & Social Sciences
open access

Sub-Antarctic Freshwater Invertebrate Thermal Tolerances: An Assessment of Critical Thermal Limits and Behavioral Responses

Description: Describes study which assessed the upper (CTmax) and lower (CTmin) thermal limits of three freshwater macroinvertebrate taxa with restricted low elevation distribution (20 m a.s.l.) and three taxa restricted to upper elevations (480 and 700 m a.s.l.) in the Magellanic sub-Antarctic ecoregion of southern Chile, and argues that their low tolerance to temperature increase can make them useful as indicators of thermal alteration in their habitats.
Date: February 4, 2020
Creator: Rendoll Cárcamo, Javier; Contador, Tamara; Convey, Peter & Kennedy, James H.
Item Type: Refine your search to only Article
Partner: UNT College of Science
open access

Field environmental philosophy and biocultural conservation at the Omora Ethnobotanical Park: Methodological approaches to broaden the ways of integrating the social component ("S") in Long-Term Socio-Ecological Research (LTSER) Sites

Description: This article discusses field environmental philosophy and biocultural conservation methods at the Omora Ethnobotanical Park in the Cape Horn Biosphere Reserve in Chile.
Date: 2010
Creator: Rozzi, Ricardo, 1960-; Anderson, Christopher B.; Pizarro, J. Cristóbal; Massardo, Francisca; Medina, Yanet; Mansilla, Andrés O. et al.
Item Type: Refine your search to only Article
Partner: UNT College of Arts and Sciences
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Field environmental philosophy and biocultural conservation at the Omora Ethnobotanical Park: Methodological approaches to broaden the ways of integrating the social component ("S") in Long-Term Socio-Ecological Research (LTSER) Sites [Material Complementario]

Description: This article discusses field environmental philosophy and biocultural conservation methods at the Omora Ethnobotanical Park in the Cape Horn Biosphere Reserve in Chile.
Date: 2010
Creator: Rozzi, Ricardo, 1960-; Anderson, Christopher B.; Pizarro, J. Cristóbal; Massardo, Francisca; Medina, Yanet; Mansilla, Andrés O. et al.
Item Type: Refine your search to only Article
Partner: UNT College of Arts and Sciences
open access

Filosofía ambiental de campo y conservación biocultural en el Parque Etnobotánico Omora: Aproximaciones metodológicas para ampliar los modos de integrar el componente social ("S") en Sitios de Estudios Socio-Ecológicos a Largo Plazo (SESELP)

Description: This article discusses field environmental philosophy and biocultural conservation methods at the Omora Ethnobotanical Park in Chile's Cape Horn Biosphere Reserve.
Date: 2010
Creator: Rozzi, Ricardo, 1960-; Anderson, Christopher B.; Pizarro, J. Cristóbal; Massardo, Francisca; Medina, Yanet; Mansilla, Andrés O. et al.
Item Type: Refine your search to only Article
Partner: UNT College of Arts and Sciences
open access

Altitudinal gradients in Magellanic sub-Antarctic lagoons: the effect of elevation on freshwater macroinvertebrate diversity and distribution

Description: In this article, freshwater macroinvertebrate diversity associated with lakes and ponds along the altitudinal gradient of a Magellanic sub-Antarctic watershed are assessed. A monotonic decline in species richness was observed with increasing elevation, with simpler and more even community composition at higher altitude. This pattern differs from the mid-peak trend found in streams of the same watershed. Functional feeding group structure also diminished with increasing elevation.
Date: July 29, 2019
Creator: Rendoll Cárcamo, Javier; Contador, Tamara; Gañán, Melisa; Pérez Troncoso, Carolina; Maldonado Márquez, Alan; Convey, Peter et al.
Item Type: Refine your search to only Article
Partner: UNT College of Science

Evaluation of City of Denton Sub-Watershed by Benthic Macroinvertebrate Field Experimental Approach

Description: In this study, two different field experiments were designed to assess the relative influence of urbanization on benthic communities. During spring and summer, four urban and one reference sites from Denton County, Texas were selected for benthic macroinvertebrate evaluation. Statistically significant differences in colonized benthic macroinvertebrate taxa on artificial substrates were observed among the four urban sites and the reference site. Oligochaetes and chironomids were the dominant t… more
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Date: August 2006
Creator: Mahato, Mahendra
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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A polar insect's tale: Observations on the life cycle of Parochlus steinenii, the only winged midge native to Antarctica

Description: Article asserts that Antarctica and the sub-Antarctic islands include some of the world’s most extreme and pristine terrestrial habitats. The authors studied the habitat preferences and the life history of P. steinenii in Lake Kitiesh, Fildes Peninsula, King George Island over the austral summer seasons from 2014 to 2019, during short (several weeks) field expeditions.
Date: December 24, 2022
Creator: Mejias, Tamara Contador; Gañán, Melisa; Rendoll Cárcamo, Javier; Maturana, Claudia S.; Benítez, Hugo A.; Kennedy, James H. et al.
Item Type: Refine your search to only Article
Partner: UNT College of Science
open access

Ciclos de vida de insectos dulceacuícolas y cambio climático global en la ecorregión subantártica de Magallanes: investigaciones ecológicas a largo plazo en el Parque Etnobotánico Omora, Reserva de Biosfera Cabo de Hornos (55° S)

Description: This article describes long-term studies the diversity, distribution and life histories of aquatic insects associated with the Róbalo River and other streams on Navarino Island.
Date: October 14, 2014
Creator: Contador, Tamara; Kennedy, James H.; Ojeda, Jaime; Feinsinger, Peter & Rozzi, Ricardo, 1960-
Item Type: Refine your search to only Article
Partner: UNT College of Arts and Sciences
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