This project understands the lake as an ecological–social field shaped by interactions among people, water, and institutional, economic, and cultural forces. Once an active public space, the lake now faces pollution, declining use, and recurring algae blooms. Rather than treating algae as waste, the thesis proposes a seasonal architecture that harvests excess algae and transforms it into a bio-material for production, exhibition, and public learning. The system follows ecological cycles: summer supports algae harvesting, workshops, and material fabrication, while winter hosts education and exhibitions using the materials produced. Algae collected by harvesting boats moves through drying, filtration, grinding, purification, and fabrication within an open, accessible environment. Operating across multiple scales, parts of the architecture float to minimize ecological impact. A structural grid balances fixed and adaptable spaces, where flexible algae wall components shape spatial experience. Visual connections invite visitors to observe processes, engage with the material, and participate throughout the year.