The study investigates the role of red algae (Rhodophyta) in biomonitoring coastal ecosystems in the Black Sea, highlighting their dominance in species composition and ability to accumulate heavy metals. It discusses the use of red algae as biomarkers for marine pollution and their significance in assessing and managing ecosystem health. Findings indicate that red algae serve as indicators of heavy metal contamination and play a critical role in the structure and function of sublittoral phytocenoses.