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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