Biological growth properties of marine Enteromorpha–diatoms and its adhesion evolution on mortar surfaces

Most research on bio-corroded mortar has focused on cyanobacteria and microorganisms in the marine environment, but the specific mechanism of mortar performance at different stages of the biological system of the marine dominant algae Enteromorpha–diatoms (ED) is still lacking. The growth characteristics of ED proliferation organisms and their attachment evolution on mortar were therefore investigated. First, the concentration of Enteromorpha spores over 0–15 days was studied. Subsequently, the effects of ED on the properties of mortar at different growth stages over 0–360 days were investigated through changes in pH, dissolved oxygen (DO), microstructure, mineral composition, and microstructure in the culture medium. The results showed that ED organisms significantly affected the pH and DO in water through photosynthesis and metabolic activities. Additionally, the adhesion of ED organisms significantly impacted the mechanical properties of the mortar, with compressive strength decreasing by 46.1% and flexural strength decreasing by 39.0% over 0–360 days. Furthermore, the formation of biofilm, the deposition of calcium carbonate, and the accumulation of organic and inorganic substances altered the microstructure of the mortar, changing its electrochemical characteristics. The electric flux change rate was 46.1% and the internal impedance decreased by 59% over 0–360 days.