Linking morphology-based functional groups to photosynthetic performance: photochemical efficiency as a monitoring tool in tropical urban ponds
Year: 2026
Type: article
Abstract: Phytoplankton effective quantum yield of Photosystem II ( Fv’/Fm’ ) is a sensitive indicator of aquatic ecosystem health, yet it remains underutilized in tropical freshwaters. We evaluated the diurnal and seasonal variations of Fv’/Fm’ and its relationship with Morphology-Based Functional Groups (MBFGs) in a hypereutrophic tropical urban pond over 15 months. In situ measurements of Fv’/Fm’ (without dark acclimation) and limnological parameters were recorded five times daily, alongside phytoplankton community sampling. Fv’/Fm’ values were consistently low throughout the study, indicating chronic physiological stress. Linear mixed-effects models and redundancy analysis identified electrical conductivity and photosynthetically active radiation (PAR) as the primary negative drivers of physiological efficiency and major determinants of community structure. Seasonal hydrological shifts, rather than short-term diurnal variations, dictated community dynamics. Small organisms (Group I) dominated the dry season under high PAR, whereas large bloom-forming cyanobacteria (Groups VII/VIII) and flagellates (Group V) dominated the rainy season, driven by elevated conductivity. These findings establish active fluorescence as a robust, real-time monitoring tool for tropical freshwaters, demonstrating that chronic environmental stressors, particularly electrical conductivity, overshadow traditional factors in shaping the physiological limits and functional structure of phytoplankton assemblages.
Source: Hydrobiologia
Institution: Universidade Federal do Espírito Santo
Language: English
Subfield: Environmental Chemistry
Field: Environmental Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $2,490
OpenAlex ID: W7204852379