Abstract
Aquatic systems are complex systems due to the environmental pressures that lead to water quality parameter changes, and consequently, variations in optically active compounds (OAC). In cascading reservoir systems, such as the Tietê Cascade Reservoir System (TCSR), which has a length of 1100 km, the horizontal gradients are expressive due to the filtration process that is caused by the sequence of dams affecting the light absorption throughout the cascade. Our new observations showed that colored dissolved organic matter (CDOM) dominate two reservoirs; non-algae particles (NAP) dominate one, and phytoplankton dominates the other. The variability of light absorption along the cascade indicates the influence of watershed dynamics in the reservoirs as much as the flow driven by previous reservoirs. Despite the effect of the variability of light absorption, light absorption by phytoplankton strongly affects the total absorption in the four reservoirs in TCSR. The results obtained in this work may enable a better understanding of how the gradient pattern changes primary production and indicates a challenge in retrieving OAC concentrations using a bio-optical model for an entire cascade composed of different optical environments.
Highlights
Water quality monitoring has been efficiently performed via remotely sensed data, using empirical and analytical models, and when applied to time-series images, it provides synoptic scale observations [1,2,3,4]
We considered 443 nm as a reference wavelength, due to its relation to dissolved organic matter concentration [39] and the marked Chl-a pigment absorption feature [4,40]; it is the central wavelength of the first OLI spectral band
The present results allowed an analysis of the dynamics of a cascading reservoir system, showing the continuous longitudinal gradient of optical absorptions and
Summary
Water quality monitoring has been efficiently performed via remotely sensed data, using empirical and analytical models, and when applied to time-series images, it provides synoptic scale observations [1,2,3,4]. The success of remote sensing applications to aquatic systems depends on the understanding of underwater light interactions with the optically active compounds (OACs) [5]. These interactions are expressed by inherent optical properties (IOPs), the absorption and scattering of light, and the OACs are represented by chlorophyll-a (Chl-a), suspended particulate matter (SPM), and colored dissolved organic matter (CDOM) [5]. The newest studies have been developed to classify the inland water systems [18,19,20] and overcome the challenge of bio-optical modeling in such environments [21]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
