Impact of diverse organic phosphorus sources on cyanobacterial growth and activity

Cyanobacteria, known for their ecological significance and role in biogeochemical cycles, exhibit varied responses to different phosphorus (P) sources. This study investigates the impact of various organic phosphorus sources on the growth and metabolic activity of cyanobacteria. Utilizing a range of organic-P compounds, including glycerophosphate, and nucleotides, the bioavailability and influence on cyanobacterial proliferation has been assessed in terms of growth-pattern. Experimental cultures were monitored for changes in biomass (in terms of O.D.) related to phosphorus metabolism under different organic-P incubated growth conditions. Our findings reveal distinct differences in cyanobacterial organic-P responses, with certain organic-P sources significantly enhancing growth and photosynthetic efficiency, while others showed limited assimilation. These variations underscore the importance of phosphorus speciation in aquatic ecosystems and its potential implications for cyanobacterial blooms. The study also highlights the adaptive mechanisms employed by cyanobacteria to utilize different organic phosphorus compounds, contributing to a deeper understanding of nutrient dynamics and their role in primary production. These insights are crucial for developing strategies to manage cyanobacterial populations in natural and engineered environments, particularly in the context of eutrophication and water quality management. The results showed that inorganic phosphorus (K₂HPO₄) led to significantly higher growth yields, with an increase of 303% compared to P-stressed conditions. In comparison, organic phosphorus sources also enhanced growth but to a lesser extent: pNPP (203%), G-6-P (196%), beta-glycerophosphate (188%), and ATP (166%). This indicates that while inorganic phosphorus supplementation is highly effective for promoting cyanobacterial growth, organic phosphorus sources can still serve as provisional nutrients, albeit less efficiently. This study highlights the potential of organic phosphorus as a supplementary nutrient source, though inorganic phosphorus remains the preferred and more efficient option for supporting cyanobacterial proliferation.