Underwater Optical Properties of Lake Texoma (Oklahoma-Texas) Using Secchi Disk, Submarine Photometer, and High-Resolution Spectroscopy (open access)

Underwater Optical Properties of Lake Texoma (Oklahoma-Texas) Using Secchi Disk, Submarine Photometer, and High-Resolution Spectroscopy

The underwater optical climate of Lake Texoma was measured at eleven fixed stations from August 1996 to August 1997. Secchi transparency and submarine photometry characterized seasonal and spatial values of secchi depth (SD), vertical attenuation coefficient (η''), and depth of euphotic zone (Zeu). Indices of Zeu:SD and η'' × SD were compared with universally applied values derived from inland and coastal waters. Turbidity explained 76% of the variation (p = 0.0001) of η'' among water quality parameters, including chlorophyll-α. Using a spectroradiometer, spectral signatures of chlorophyll-α and turbidity were located. Stations with low turbidity exhibited a distinct green reflectance peak around 590-610 nanometers, indicating presence of chlorophyll-α. Stations with high turbidity exhibited a reflectance peak shift towards the red spectrum, making it difficult to detect the chlorophyll signature. Derivative analysis of the reflectance signal at 590-610, and 720-780 nanometers allowed discrimination of this chlorophyll signature from those of turbidity (0.66 ≤ r^2 ≤ 0.99).
Date: August 1998
Creator: Rolbiecki, David A. (David Alan)
System: The UNT Digital Library
Spatial and Temporal Patterns of Areal and Volumetric Phytoplankton Productivity of Lake Texoma (open access)

Spatial and Temporal Patterns of Areal and Volumetric Phytoplankton Productivity of Lake Texoma

Phytoplankton productivity of Lake Texoma was measured for one year from August 1999 to August 2000 for four stations, using the oxygen change method and laboratory incubation. Mean values of the photosynthetic parameters, PBmax and alphaB ranged from 4.86 to 46.39 mg O2.mg Chl-1.hr-1 for PBmax and 20.06 to 98.96 mg O2.mg Chl-1.E-1.m2 for alphaB. These values were in the range to be expected for a highly turbid, temperate reservoir. Estimated gross annual areal productivity ranged from 594 g C.m2.yr-1 (P.Q. = 1.2), at a station in the Washita River Zone to 753 g C.m2.yr-1 at a station in the Red River Zone, of the reservoir. Gross annual areal productivity at Station 17, in the Main Lake Zone, was 708 g C.m2.yr-1. Gross areal and volumetric productivity showed distinct seasonal variation with Photosynthetically Available Radiation (PAR) and temperature. Trophic status estimated on a station-by-station basis, using net productivity values derived from gross productivity and respiration estimates, was mesotrophic for all the stations, though one station approached eutrophy. Net productivity values ranged from 0.74 to 0.91 g C. m-2.d-1. An algal bioassay conducted at two stations in August 2000, revealed that phosphorus was most likely the nutrient limiting photosynthesis at both …
Date: August 2001
Creator: Baugher, Tessy
System: The UNT Digital Library
The Stoneflies (Plecoptera) of the Ozark and Ouachita Mountains (open access)

The Stoneflies (Plecoptera) of the Ozark and Ouachita Mountains

Collections of stoneflies (Plecoptera) were made at 603 stream sites from Nov. 1983 - May 1988 in the Ozark-Ouachita Mountain region, in relation to physiographic and vegetational characteristics. Examination of approximately 9000 vials from these collections, supplemented with material from major museums and other collectors, revealed 88 stonefly species in 8 families and 24 genera. Pearson's measure of association (R) showed there was a significant association between species present and each of the tested variables.
Date: December 1989
Creator: Poulton, Barry C. (Barry Charles)
System: The UNT Digital Library
Spatial and Temporal Influences of Water Quality on Zooplankton in Lake Texoma (open access)

Spatial and Temporal Influences of Water Quality on Zooplankton in Lake Texoma

Seventy-one aquatic species including the copepodids and nauplii were identified from Lake Texoma from August 1996 to September 1997. Zooplankton community structure, abundance and spatial and temporal distributions were compared among five lake zones delineated a priori based on chloride concentration. The zones, in order of decreasing chloride concentration, are the Red River zone (RRZ), Red river Transition zone (RRTZ), Main Lake zone (MLZ), Washita River Transition zone (WRTZ) and Washita River zone (WRZ). Bray Curtis Similarity Index showed community structure was most similar in the two Red River arm zones, the two Washita River arm zones and the MLZ. Zooplankton abundance was greatest in the Red River arm (312 org/L), intermediate in the Washita River arm (217 org/L) and least in the Main Lake body (103 org/L). A significant increase in the abundance of a deformed rotifer, Keratella cochlearis, was observed mainly in the Red River arm during a second study from March 1999 to June 1999. Seasonal dynamics, rather than spatial dynamics, were more important in structuring the zooplankton community, especially in the two river arms. Spatial variance was solely attributed to station and zone effects independent of time for a few crustacean species and many of the …
Date: May 2000
Creator: Franks, Jessica L.
System: The UNT Digital Library
Life History of Mayatrichia ponta Ross (Trichoptera: Hydroptilidae) in Honey Creek, Turner Falls Park, Oklahoma (open access)

Life History of Mayatrichia ponta Ross (Trichoptera: Hydroptilidae) in Honey Creek, Turner Falls Park, Oklahoma

The life history and ontogenetic microhabitat change of Mayatrichia ponta Ross were investigated in Honey Creek, Turner Falls Park, Murray Co., Oklahoma, U.S.A. from August 1994 to August 1995. The shape of larval cases changed from a small cone to a cylinder. M. ponta had an asynchronous multivoltine life history with considerable cohort and generation overlap; five generations were estimated. The development rate was reduced in winter. The winter generations of M. ponta had wider head capsule widths (136-165 μm) than summer generations (121-145 μm). The sex ratio of adults was 1.43 ♂ : 1 ♀. Fecundity ranged from 46 to 150 eggs/female. Fifth instar larvae and pupae aggregated on the bottom side of substrates. Early instars were distributed evenly on all sides of substrates. General patterns of ontogenetic microhabitat shift in aquatic insects are categorized as flow mediated, flow independent, and population interactions and other resources mediated.
Date: December 1997
Creator: Wang, Yi-Kuang
System: The UNT Digital Library
Biodiversity of Dragonflies and Damselflies (Odonata) of the South-Central Nearctic and Adjacent Neotropical Biotic Provinces (open access)

Biodiversity of Dragonflies and Damselflies (Odonata) of the South-Central Nearctic and Adjacent Neotropical Biotic Provinces

The south-central United States serves as an important biogeographical link and dispersal corridor between Nearctic and Neotropical elements of western hemisphere odonate faunas. Its species are reasonably well known because of substantial collections, but there has been no concerted effort to document the extent of biodiversity and possible geographic affinities of dragonflies and damselflies of this region. The recent discoveries of Argia leonorae Garrison, Gomphus gonzalezi Dunkle and Erpetogomphus heterodon Garrison from southern and western Texas and northern Mexico suggest that Odonata species remain to be discovered in this area, particularly from far south Texas and northern Mexico. I have documented a total of 12,515 records of Odonata found in 408 counties within the south-central U.S. A total of 73 species of damselflies and 160 species of dragonflies was revealed in the region. The 233 (197 in Texas) Odonata species are distributed among 10 families and 66 genera. Illustrated family, generic, and species-level keys are provided. Since the beginning of this work in the Fall of 1993, one species has been added each to the Louisiana and Oklahoma faunas, and 12 species have been added, previously unreported from Texas, including four new to the U.S. The area of highest Odonata …
Date: May 1999
Creator: Abbott, John C.
System: The UNT Digital Library
Emergence, Growth, Drift and Microdistribution of Stoneflies (Plecoptera) in an Ozark Foothills Stream, Delaware County (open access)

Emergence, Growth, Drift and Microdistribution of Stoneflies (Plecoptera) in an Ozark Foothills Stream, Delaware County

Adult stonefly emergence, nymphal growth, drift and microdistribution were examined in Battle Branch, a secondorder, spring-fed stream, from November, 1982 to May, 1984. Adults of 22 species emerged successionally, with specific adults present every month. Searching emergent objects and the stream margin was best for collection of winter and early spring emerging species. Sweeping the streamside and light trapping were most efficient for late spring and summer emerging species. Nymphal growth for nine abundant species generally fit double log or semilog models. Drift was low, but did show a post-sunset pulse. Generally, leaf material was found to be significantly related (p<O.001) to density, diversity and biomass of stoneflies in Battle Branch.
Date: May 1985
Creator: Ernst, Mark R. (Mark Richard)
System: The UNT Digital Library
Drumming Behavior of Selected North American Stoneflies (Plecoptera) (open access)

Drumming Behavior of Selected North American Stoneflies (Plecoptera)

Drumming is first described for five North American stonefly species, Acroneuria evoluta, Doroneuria baumanni, Isoperla namata, Chernokrilus misnomus, and Pictetiella expansa. Signals of Acroneuria lycorias, Phasganophora capitata and Isoperla signata are further described. Drumming was not recorded from Amhinemura delosa. Signals of A. evoluta are the most complex yet recorded in Plecoptera. Doroneuria baumanni, P. expanse, C. misnomus and P. capitata have 2-way exchanges. Male D. baumanni produce two prolonged beats by rubbing the hammer on the substratum; male-female signals are non-overlapping in the first two species and overlapping in the latter two. Female P. capitata answered with an unusually long sequence of beats. Two male Isoperla species produced monophasic calls without female answers. Female A. lycorias answered taped male signals with monophasic signals like all observed females.
Date: December 1983
Creator: Maketon, Monchan
System: The UNT Digital Library
Seasonal and Spatial Variability of the Microcrustacean Community in Lake Texoma, Texas and Oklahoma (open access)

Seasonal and Spatial Variability of the Microcrustacean Community in Lake Texoma, Texas and Oklahoma

Twenty-eight species of zooplankton were identified from Lake Texoma. Seasonal density of the overall microcrustacean community and seasonal cycles of individual species were compared with northern populations and any available literature from the Southwest. Cycles of occurrence and abundance were similar to those observed in northern populations but tended to occur earlier in the year due to higher temperatures. Spatial distributions within the reservoir were heavily influenced by nutrient and salt input from the Red River, which resulted in dense populations in the Red River Arm. In addition, during the summer, the microcrustacean community was restricted to the epilimnion due to anoxic conditions in the hypolimnion of the reservoir.
Date: August 1980
Creator: Crist, Lawrence W.
System: The UNT Digital Library
Developing a Forest Gap Model to Be Applied to a Watershed-scaled Landscape in the Cross Timbers Ecoregion Using a Topographic Wetness Index (open access)

Developing a Forest Gap Model to Be Applied to a Watershed-scaled Landscape in the Cross Timbers Ecoregion Using a Topographic Wetness Index

A method was developed for extending a fine-scaled forest gap model to a watershed-scaled landscape, using the Eastern Cross Timbers ecoregion as a case study for the method. A topographic wetness index calculated from digital elevation data was used as a measure of hydrologic across the modeled landscape, and the gap model modified to have with a topographically-based hydrologic input parameter. The model was parameterized by terrain type units that were defined using combinations of USDA soil series and classes of the topographic wetness index. A number of issues regarding the sources, grid resolutions, and processing methods of the digital elevation data are addressed in this application of the topographic wetness index. Three different grid sizes, 5, 10, and 29 meter, from both LiDAR-derived and contour-derived elevation grids were used, and the grids were processed using both single-directional flow algorithm and bi-directional flow algorithm. The result of these different grids were compared and analyzed in context of their application in defining terrain types for the forest gap model. Refinements were made in the timescale of gap model’s weather model, converting it into a daily weather generator, in order to incorporate the effects of the new topographic/hydrologic input parameter. The precipitation …
Date: August 2014
Creator: Goetz, Heinrich (Heinrich Erwin)
System: The UNT Digital Library
Pelagic Phytoplankton and Physicochemical Correlates for Lake Texoma (open access)

Pelagic Phytoplankton and Physicochemical Correlates for Lake Texoma

An analysis and correlation of phytoplankton communities with physicochemical data from 3 sites in Lake Texoma was conducted to supplement time-series data. Water and phytoplankton were sampled monthly, March, 1976-February, 1977. Simple correlations were run between all physicochemical parameters and phytoplankton standing crop from the 3 sites. Multiple linear regression analyses were used to develop equations predictive of phytoplankton standing crop and chloride concentration. Minerals leached from marine sediments in the Red River chennel contribute to formation of a, halocline which seals the anoxic hypolimnion from the reservoir surface in midsummer. Conductivity decreased west to east, 2980-1800. pmhos/cm. Maximum mean annual phytoplankton standing crop in Red River arm was 36 percent greater than midlake. Eutrophication was evident.
Date: December 1978
Creator: McCullough, William P.
System: The UNT Digital Library