Effect of controlled pH on the biochemical characteristics of estuarine phototrophic biofilms

Abstract

The intertidal zone is a sensitive indicator of climate change, with wide-ranging human activity and related impacts on the surrounding ecosystems. The changed pH of estuarine water by modifying factors such as oil spills, AMD, or pollution may alter the solubility and bioavailability of some nutrients and contaminants, potentially perturbing marine ecosystems and the organisms that inhabit them. As primary producers, Cyanobacteria form one of the bases for aquatic ecosystems. Seawater pH is crucial in impacting biochemical reactions, nutrient availability, and the health of marine organisms. Changes in its pH could alter the stability of the ecosystems and biodiversity. Shifts in pH will affect photosynthetic efficiency, nutrient uptake, and community composition, impacting the entire food web and biogeochemical cycles in marine environments. This underlines the importance of pH stability during cyanobacterial cultivation and emphasizes optimizing growth conditions to enhance biomass and extracellular polymeric substances (EPS) production. The discovered results bear tremendous importance for studying biotechnological applications of cyanobacteria with a focus on biofilm-based systems. The present thesis focuses on studying the effects of different pH regimes on growth, photosynthetic pigment concentrations, and EPS production in cyanobacterial biofilms isolated from the Sundarbans.