Research Article
Underwater Optical Properties of Lake Texoma (Oklahoma-Texas) Using Secchi Disk, Submarine Photometer, and High-resolution Spectroscopy
David Alan Rolbiecki*
Issue:
Volume 10, Issue 2, June 2025
Pages:
34-103
Received:
7 May 2025
Accepted:
6 June 2025
Published:
23 June 2025
DOI:
10.11648/j.eeb.20251002.11
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Abstract: This research represents the author’s thesis, which was completed in 1998, in partial fulfilment of the Master of Science degree in biology from the University of North Texas, Denton, United States, culminating in twelve months of field collection carried out in conjunction with the Lake Texoma Water Quality Monitoring Program (WQMP) funded by the U.S. Army Corps of Engineers, Tulsa District. The purpose of this research was to characterize the underwater light regime in Lake Texoma using secchi disk, submarine photometer, and high-resolution spectroscopy at eleven fixed stations from August 1996 to August 1997. The objectives of this research was to 1) measure Secchi transparency at each station with submarine photometry to characterize seasonal and spatial values of secchi depth (SD); 2) determine vertical attenuation coefficients (η”) and depth of euphotic zone (Zeu); 3) Compare secchi depth (SD), Zeu, and η” with published data taken from other water bodies; 4) Model SD and η” with water quality parameters taken during the sampling periods; 5) Obtain spectral data in narrow bandwidths from 300 to 800nm using high-resolution spectroscopy; 6) Examine spectral irradiance, reflectance, and attenuation in the green (500-600nm), red (600-700nm), and near-infrared (700-800nm) spectrum; and 7) Model reflectance spectra with water quality parameters taken during the sampling periods. Indices of Zeu: SD and η” x SD were compared with universally applied values derived from published research of inland and coastal waters. Turbidity explained 76% of the variation (p = 0.0001) of η” among water quality parameters, including chlorophyll-a. Spectral signatures of chlorophyll-a and turbidity were measured with the spectroradiometer and quantified. Stations with low turbidity exhibited a distinct green reflectance peak around 590-610 nanometers, indicating presence of chlorophyll-a. 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 < r2 < 0.99).
Abstract: This research represents the author’s thesis, which was completed in 1998, in partial fulfilment of the Master of Science degree in biology from the University of North Texas, Denton, United States, culminating in twelve months of field collection carried out in conjunction with the Lake Texoma Water Quality Monitoring Program (WQMP) funded by the ...
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Research Article
Comparison of Specific Ecological Parameters of Nematodes in Six Common Fish Species from the Senegal River and the Gambia River
Issue:
Volume 10, Issue 2, June 2025
Pages:
104-114
Received:
11 May 2025
Accepted:
27 May 2025
Published:
30 June 2025
DOI:
10.11648/j.eeb.20251002.12
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Abstract: The Senegal River and the Gambia River share the same sedimentary basin, the same source, and have geographical proximity. This study, conducted over three consecutive years in the Senegal River and the Gambia River, aimed to perform a comparative analysis of the prevalence, abundance, mean intensity, and abundance index of nematodes in six fish species common to both locations: Citharinus citharus, Clarias gariepinus, Chrysichthys maurus, Hydrocynus forskahlii, Mormyrops anguilloides, and Synodontis ocellifer. The inventory of parasitic nematodes in these fish revealed that Chrysichthys maurus hosts the highest diversity of parasitic nematodes, with nine genera identified. Citharinus citharus and Mormyrops anguilloides are each parasitized by only one nematode genus, Cithariniella and Contracaecum, respectively. Except of Spirocamallanus and Camallanus, which were found exclusively in C. maurus, most nematode genera are shared among the different fish hosts. The genus Anisakis exhibits the highest prevalence, with 29.03% in the Senegal River, while Cithariniella shows the highest abundance, mean intensity, and abundance index. Other nematode genera, such as Paracamallanus, Procamallanus, Rhabdochona, Contracaecum, Spirocamallanus, Spinitectus, and Falcaustra, display variable ecological parameters. These nematodes are distributed within the liver and various sections of the digestive tract.
Abstract: The Senegal River and the Gambia River share the same sedimentary basin, the same source, and have geographical proximity. This study, conducted over three consecutive years in the Senegal River and the Gambia River, aimed to perform a comparative analysis of the prevalence, abundance, mean intensity, and abundance index of nematodes in six fish sp...
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