Modeling of algal periphyton growth rate: Taking into account the feedback effects of biomass accumulation

The concept of periphyton growth is globally regarded as a functional unit, without considering the dynamics of various components as have been reported by earlier scholars, and is used as references to the algal periphyton growth modeling conducted in this study. Experimental data on the growth of periphyton biomass versus time was used to test two basic hypotheses to account for feedback effects on periphyton growth. Modeling curves and experimental data showed that biomass grew exponentially between 14 and 28 days. Between 21and 28 days, the two functions of reduction rate and coefficient value {reduction of the growth rate = f (biomass)} has a more important role. This model takes into account the decline in the growth rate of drop- out processes and biomass retroactive effect. However, it shows great point of progress to achieve a mathematical expression that is reliable and able to effectively shorten the actions of abiotic variables and interactions among complex and ever changing units.